diff mbox series

drm/bridge:anx7625: Enable DSC feature

Message ID 20250213123331.3016824-1-xji@analogixsemi.com (mailing list archive)
State New
Headers show
Series drm/bridge:anx7625: Enable DSC feature | expand

Commit Message

Xin Ji Feb. 13, 2025, 12:33 p.m. UTC
As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and internal
pixel clock(maximum 300M) limitation. Anx7625 must enable DSC feature
while MIPI source want to output 4K30 resolution.

Signed-off-by: Xin Ji <xji@analogixsemi.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 300 ++++++++++++++++++----
 drivers/gpu/drm/bridge/analogix/anx7625.h |  32 +++
 2 files changed, 284 insertions(+), 48 deletions(-)

Comments

Dmitry Baryshkov Feb. 13, 2025, 1:04 p.m. UTC | #1
On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and internal
> pixel clock(maximum 300M) limitation. Anx7625 must enable DSC feature
> while MIPI source want to output 4K30 resolution.

This commit message is pretty hard to read and understand for a
non-native speaker. Please consider rewriting it so that it is easier to
understand it.

> 
> Signed-off-by: Xin Ji <xji@analogixsemi.com>
> ---
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 300 ++++++++++++++++++----
>  drivers/gpu/drm/bridge/analogix/anx7625.h |  32 +++
>  2 files changed, 284 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 4be34d5c7a3b..7d86ab02f71c 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -22,6 +22,7 @@
>  
>  #include <drm/display/drm_dp_aux_bus.h>
>  #include <drm/display/drm_dp_helper.h>
> +#include <drm/display/drm_dsc_helper.h>
>  #include <drm/display/drm_hdcp_helper.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_bridge.h>
> @@ -476,6 +477,138 @@ static int anx7625_set_k_value(struct anx7625_data *ctx)
>  				 MIPI_DIGITAL_ADJ_1, 0x3D);
>  }
>  
> +static int anx7625_set_dsc_params(struct anx7625_data *ctx)
> +{
> +	int ret, i;
> +	u16 htotal, vtotal;
> +
> +	if (!ctx->dsc_en)
> +		return 0;
> +
> +	/* Htotal */
> +	htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> +		ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> +	ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				HORIZONTAL_TOTAL_PIXELS_L, htotal);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> +	/* Hactive */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_ACTIVE_PIXELS_L,
> +				 ctx->dt.hactive.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_ACTIVE_PIXELS_H,
> +				 ctx->dt.hactive.min >> 8);
> +	/* HFP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_FRONT_PORCH_L,
> +				 ctx->dt.hfront_porch.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_FRONT_PORCH_H,
> +				 ctx->dt.hfront_porch.min >> 8);
> +	/* HWS */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_SYNC_WIDTH_L,
> +				 ctx->dt.hsync_len.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_SYNC_WIDTH_H,
> +				 ctx->dt.hsync_len.min >> 8);
> +	/* HBP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_BACK_PORCH_L,
> +				 ctx->dt.hback_porch.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 HORIZONTAL_BACK_PORCH_H,
> +				 ctx->dt.hback_porch.min >> 8);
> +	/* Vtotal */
> +	vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> +		 ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
> +				 vtotal);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
> +				 vtotal >> 8);
> +	/* Vactive */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_L,
> +				 ctx->dt.vactive.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_H,
> +				 ctx->dt.vactive.min >> 8);
> +	/* VFP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> +	/* VWS */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> +	/* VBP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 VERTICAL_BACK_PORCH, ctx->dt.vback_porch.min);

This code mostly duplicates anx7625_dsi_video_timing_config() with the
I2C client being the only difference. Please consider extracting a
common helper to write the timings.

> +
> +	/* Htotal */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_L_7E,
> +				 htotal);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_H_7E,
> +				 htotal >> 8);
> +	/* Hactive */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> +	/* HFP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 HORIZON_FRONT_PORCH_L_7E,
> +				 ctx->dt.hfront_porch.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 HORIZON_FRONT_PORCH_H_7E,
> +				 ctx->dt.hfront_porch.min >> 8);
> +	/* HWS */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 HORIZON_SYNC_WIDTH_L_7E,
> +				 ctx->dt.hsync_len.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 HORIZON_SYNC_WIDTH_H_7E,
> +				 ctx->dt.hsync_len.min >> 8);
> +	/* HBP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 HORIZON_BACK_PORCH_L_7E,
> +				 ctx->dt.hback_porch.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 HORIZON_BACK_PORCH_H_7E,
> +				 ctx->dt.hback_porch.min >> 8);
> +
> +	/* Config DSC decoder internal blank timing for decoder to start */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 H_BLANK_L,
> +				 dsc_div(htotal - ctx->dt.hactive.min));
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 H_BLANK_H,
> +				 dsc_div(htotal - ctx->dt.hactive.min) >> 8);
> +
> +	/* Compress ratio  RATIO bit[7:6] */
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> +				(5 - DSC_COMPRESS_RATIO) << 6);
> +	/*PPS table*/
> +	for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> +		ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> +					       R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> +					       &ctx->pps_table[i]);
> +
> +	return ret;
> +}
> +
> +static int anx7625_timing_write(struct anx7625_data *ctx,
> +				struct i2c_client *client,
> +				u8 reg_addr, u16 reg_val, bool high_byte)
> +{
> +	u8 reg_data;
> +
> +	if (ctx->dsc_en)
> +		reg_val = dsc_div(reg_val);
> +
> +	reg_data = (high_byte ? (reg_val >> 8) : reg_val) & 0xFF;
> +
> +	return anx7625_reg_write(ctx, client, reg_addr, reg_data);
> +}

Ugh, no. Calculate htotal in the calling function and call
anx7625_reg_write() as you were doing that before.

> +
>  static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
>  {
>  	struct device *dev = ctx->dev;
> @@ -506,34 +639,33 @@ static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
>  	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
>  				MIPI_LANE_CTRL_0, ctx->pdata.mipi_lanes - 1);
>  
> -	/* Htotal */
>  	htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> -		ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> +			 ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> +	/* Htotal */
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_TOTAL_PIXELS_H, htotal, true);
>  	/* Hactive */
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min, false);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min, true);
>  	/* HFP */
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_FRONT_PORCH_H,
> -			ctx->dt.hfront_porch.min >> 8);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min, false);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_FRONT_PORCH_H, ctx->dt.hfront_porch.min, true);

Are porches also compressed? I think blanking signal timings are
transferred as is, without compression.

>  	/* HWS */
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min, false);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min, true);
>  	/* HBP */
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> -	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> -			HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min, false);
> +	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min, true);
>  	/* Vactive */
>  	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
>  			ctx->dt.vactive.min);
> @@ -663,9 +795,15 @@ static int anx7625_dsi_config(struct anx7625_data *ctx)
>  
>  	DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
>  
> -	/* DSC disable */
> -	ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> -				R_DSC_CTRL_0, ~DSC_EN);
> +	ret = anx7625_set_dsc_params(ctx);
> +	if (ctx->dsc_en)
> +		/* DSC enable */
> +		ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +					R_DSC_CTRL_0, DSC_EN);
> +	else
> +		/* DSC disable */
> +		ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +					 R_DSC_CTRL_0, ~DSC_EN);
>  
>  	ret |= anx7625_api_dsi_config(ctx);
>  
> @@ -2083,6 +2221,7 @@ static int anx7625_setup_dsi_device(struct anx7625_data *ctx)
>  		MIPI_DSI_MODE_VIDEO_HSE	|
>  		MIPI_DSI_HS_PKT_END_ALIGNED;
>  
> +	dsi->dsc = &ctx->dsc;
>  	ctx->dsi = dsi;
>  
>  	return 0;
> @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct drm_bridge *bridge,
>  	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
>  	struct device *dev = ctx->dev;
>  
> -	DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> +	dev_dbg(dev, "drm mode checking\n");
> +	if (mode->clock > SUPPORT_PIXEL_CLOCK)
> +		return MODE_CLOCK_HIGH;
> +
> +	if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> +		return MODE_CLOCK_LOW;
>  
> -	/* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> -	if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> -		DRM_DEV_DEBUG_DRIVER(dev,
> -				     "drm mode invalid, pixelclock too high.\n");
> +	if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3 != 0))

Magic number 3. Also is it actually required? I think DSC standard has
no such requirement.

>  		return MODE_CLOCK_HIGH;
> -	}
>  
> -	DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> +	dev_dbg(dev, "drm mode valid.\n");
>  
>  	return MODE_OK;
>  }
>  
> +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en)
> +{
> +	int ret;
> +	struct device *dev = ctx->dev;
> +
> +	ctx->dsc_en = en;
> +
> +	if (en) {
> +		ctx->dsc.dsc_version_major = 1;
> +		ctx->dsc.dsc_version_minor = 1;
> +		ctx->dsc.slice_height = 8;
> +		ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> +		ctx->dsc.slice_count = DSC_SLICE_NUM;
> +		ctx->dsc.bits_per_component = 8;
> +		ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> +		ctx->dsc.block_pred_enable = true;
> +		ctx->dsc.native_420 = false;
> +		ctx->dsc.native_422 = false;
> +		ctx->dsc.simple_422 = false;
> +		ctx->dsc.vbr_enable = false;
> +		ctx->dsc.rc_model_size = DSC_RC_MODEL_SIZE_CONST;
> +		ctx->dsc.pic_width = ctx->dt.hactive.min;
> +		ctx->dsc.pic_height = ctx->dt.vactive.min;
> +		ctx->dsc.convert_rgb = 1;
> +		ctx->dsc.vbr_enable = 0;

A lot of this params should be coming from the sink device. You have to
get them from the DPCD.

> +
> +		drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> +		drm_dsc_set_const_params(&ctx->dsc);
> +
> +		ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx->dsc);
> +		ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> +		ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
> +		if (ret < 0)
> +			dev_warn(dev, "drm_dsc_setup_rc_params ret %d\n", ret);
> +
> +		drm_dsc_compute_rc_parameters(&ctx->dsc);

You have ignored return value. Please handle the function returning an
error.

> +
> +		drm_dsc_pps_payload_pack((struct drm_dsc_picture_parameter_set *)&ctx->pps_table,
> +					 &ctx->dsc);
> +		dev_dbg(dev, "anx7625 enable dsc\n");
> +	} else {
> +		ctx->dsc.dsc_version_major = 0;
> +		ctx->dsc.dsc_version_minor = 0;
> +		dev_dbg(dev, "anx7625 disable dsc\n");
> +	}
> +}
> +
>  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
>  				    const struct drm_display_mode *old_mode,
>  				    const struct drm_display_mode *mode)
> @@ -2244,6 +2431,11 @@ static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
>  	DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
>  			     mode->vsync_end,
>  			     mode->vtotal);
> +
> +	if (mode->clock > DSC_PIXEL_CLOCK)

What if the sink doesn't support DSC? The decision whether to enable DSC
or not should be happening in the atomic_check(). Likewise mode_valid
should be able to check if your bridge and the sink can agree on DSC
params and reject modes if they can not.

> +		anx7625_dsc_enable(ctx, true);
> +	else
> +		anx7625_dsc_enable(ctx, false);
>  }
>  
>  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> @@ -2258,26 +2450,33 @@ static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
>  
>  	DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
>  
> -	/* No need fixup for external monitor */
> -	if (!ctx->pdata.panel_bridge)
> -		return true;
> -
>  	hsync = mode->hsync_end - mode->hsync_start;
>  	hfp = mode->hsync_start - mode->hdisplay;
>  	hbp = mode->htotal - mode->hsync_end;
>  	hblanking = mode->htotal - mode->hdisplay;
>  
> -	DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> -	DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> -			     hsync, hfp, hbp, adj->clock);
> -	DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> -			     adj->hsync_start, adj->hsync_end, adj->htotal);
> -
> +	dev_dbg(dev, "before mode fixup\n");
> +	dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> +		hsync, hfp, hbp, adj->clock);
> +	dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> +		adj->hsync_start, adj->hsync_end, adj->htotal);

No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway, this
should go to a separate commit.

>  	adj_hfp = hfp;
>  	adj_hsync = hsync;
>  	adj_hbp = hbp;
>  	adj_hblanking = hblanking;
>  
> +	if (mode->clock > DSC_PIXEL_CLOCK) {
> +		adj_hsync = DSC_HSYNC_LEN;
> +		adj_hfp = DSC_HFP_LEN;
> +		adj_hbp = DSC_HBP_LEN;
> +		vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
> +		goto calculate_timing;
> +	}
> +
> +	/* No need fixup for external monitor */
> +	if (!ctx->pdata.panel_bridge)
> +		return true;
> +
>  	/* HFP needs to be even */
>  	if (hfp & 0x1) {
>  		adj_hfp += 1;
> @@ -2349,16 +2548,21 @@ static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
>  			adj_hfp -= delta_adj;
>  	}
>  
> -	DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> -	DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> -			     adj_hsync, adj_hfp, adj_hbp, adj->clock);
> +calculate_timing:
> +
> +	dev_dbg(dev, "after mode fixup\n");
> +	dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> +		adj_hsync, adj_hfp, adj_hbp, adj->clock);
>  
>  	/* Reconstruct timing */
>  	adj->hsync_start = adj->hdisplay + adj_hfp;
>  	adj->hsync_end = adj->hsync_start + adj_hsync;
>  	adj->htotal = adj->hsync_end + adj_hbp;
> -	DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> -			     adj->hsync_start, adj->hsync_end, adj->htotal);
> +	if (mode->clock > DSC_PIXEL_CLOCK)
> +		adj->clock = (u64)vref * adj->htotal * adj->vtotal / 1000 / 1000;
> +
> +	dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
> +		adj->hsync_start, adj->hsync_end, adj->htotal, adj->clock);
>  
>  	return true;
>  }
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
> index eb5580f1ab2f..db931f5800b1 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> @@ -149,6 +149,8 @@
>  #define HFP_HBP_DEF		((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
>  #define VIDEO_CONTROL_0	0x08
>  
> +#define  TOTAL_LINES_L          0x12
> +#define  TOTAL_LINES_H          0x13
>  #define  ACTIVE_LINES_L         0x14
>  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
>  #define  VERTICAL_FRONT_PORCH   0x16
> @@ -166,6 +168,32 @@
>  #define  HORIZONTAL_BACK_PORCH_L      0x21
>  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are reserved */
>  
> +#define  H_BLANK_L                    0x3E
> +#define  H_BLANK_H                    0x3F
> +#define  DSC_COMPRESS_RATIO           3
> +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)

This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode? Or
does 1:3 come from some other ratio?

> +#define  DSC_SLICE_NUM                2
> +#define  DSC_PIXEL_CLOCK              250000
> +#define  DSC_HSYNC_LEN                90
> +#define  DSC_HFP_LEN                  177
> +#define  DSC_HBP_LEN                  297
> +
> +#define  TOTAL_PIXEL_L_7E             0x50
> +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> +#define  ACTIVE_PIXEL_L_7E            0x52
> +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> +#define  HORIZON_BACK_PORCH_L_7E      0x58
> +#define  HORIZON_BACK_PORCH_H_7E      0x59
> +
> +#define  PPS_SIZE                     128
> +#define  PPS_BLOCK_SIZE               32
> +#define  R_PPS_REG_0                  0x80
> +#define  R_I2C_1                      0x81
> +
>  /******** END of I2C Address 0x72 *********/
>  
>  /***************************************************************/
> @@ -415,6 +443,7 @@ enum audio_wd_len {
>  #define MAX_EDID_BLOCK	3
>  #define EDID_TRY_CNT	3
>  #define SUPPORT_PIXEL_CLOCK	300000
> +#define SUPPORT_MIN_PIXEL_CLOCK	50000
>  
>  /***************** Display End *****************/
>  
> @@ -454,6 +483,7 @@ struct anx7625_data {
>  	int hpd_high_cnt;
>  	int dp_en;
>  	int hdcp_cp;
> +	bool dsc_en;
>  	/* Lock for work queue */
>  	struct mutex lock;
>  	struct device *dev;
> @@ -479,6 +509,8 @@ struct anx7625_data {
>  	struct drm_connector *connector;
>  	struct mipi_dsi_device *dsi;
>  	struct drm_dp_aux aux;
> +	struct drm_dsc_config dsc;
> +	char pps_table[PPS_SIZE];

pps_table and drm_dsc_config can vary depending on the mode and
connected sink. THey should be a part of the atomic state rather than a
long-living anx7625_data. So does dsc_en.

>  };
>  
>  #endif  /* __ANX7625_H__ */
> -- 
> 2.25.1
>
Xin Ji Feb. 14, 2025, 11:20 a.m. UTC | #2
> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Sent: Thursday, February 13, 2025 9:04 PM
> To: Xin Ji <xji@analogixsemi.com>
> Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent Pinchart
> <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>;
> Jernej Skrabec <jernej.skrabec@gmail.com>; Maarten Lankhorst
> <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>;
> Thomas Zimmermann <tzimmermann@suse.de>; David Airlie
> <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Bernie Liang
> <bliang@analogixsemi.com>; Qilin Wen <qwen@analogixsemi.com>;
> treapking@google.com; dri-devel@lists.freedesktop.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> 
> 
> On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and internal
> > pixel clock(maximum 300M) limitation. Anx7625 must enable DSC feature
> > while MIPI source want to output 4K30 resolution.
> 
> This commit message is pretty hard to read and understand for a non-native
> speaker. Please consider rewriting it so that it is easier to understand it.
> 
Thanks for the review, sorry about that, I'll rewriting the commit message
> >
> > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > ---
> >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > ++++++++++++++++++----  drivers/gpu/drm/bridge/analogix/anx7625.h |
> > 32 +++
> >  2 files changed, 284 insertions(+), 48 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > index 4be34d5c7a3b..7d86ab02f71c 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > @@ -22,6 +22,7 @@
> >
> >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > <drm/display/drm_dp_helper.h>
> > +#include <drm/display/drm_dsc_helper.h>
> >  #include <drm/display/drm_hdcp_helper.h>  #include
> > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@ -476,6
> > +477,138 @@ static int anx7625_set_k_value(struct anx7625_data *ctx)
> >                                MIPI_DIGITAL_ADJ_1, 0x3D);  }
> >
> > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > +     int ret, i;
> > +     u16 htotal, vtotal;
> > +
> > +     if (!ctx->dsc_en)
> > +             return 0;
> > +
> > +     /* Htotal */
> > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > +     /* Hactive */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > +                              ctx->dt.hactive.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > +                              ctx->dt.hactive.min >> 8);
> > +     /* HFP */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_FRONT_PORCH_L,
> > +                              ctx->dt.hfront_porch.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_FRONT_PORCH_H,
> > +                              ctx->dt.hfront_porch.min >> 8);
> > +     /* HWS */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_SYNC_WIDTH_L,
> > +                              ctx->dt.hsync_len.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_SYNC_WIDTH_H,
> > +                              ctx->dt.hsync_len.min >> 8);
> > +     /* HBP */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_BACK_PORCH_L,
> > +                              ctx->dt.hback_porch.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              HORIZONTAL_BACK_PORCH_H,
> > +                              ctx->dt.hback_porch.min >> 8);
> > +     /* Vtotal */
> > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
> > +                              vtotal);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
> > +                              vtotal >> 8);
> > +     /* Vactive */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_L,
> > +                              ctx->dt.vactive.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_H,
> > +                              ctx->dt.vactive.min >> 8);
> > +     /* VFP */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > +     /* VWS */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > +     /* VBP */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > +                              VERTICAL_BACK_PORCH,
> > + ctx->dt.vback_porch.min);
> 
> This code mostly duplicates anx7625_dsi_video_timing_config() with the I2C
> client being the only difference. Please consider extracting a common helper to
> write the timings.
It is hard to extracting a common helper, they are used different I2C slave address
and timing register need divided by 3 if DSC enabled.
> 
> > +
> > +     /* Htotal */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_L_7E,
> > +                              htotal);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_H_7E,
> > +                              htotal >> 8);
> > +     /* Hactive */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > +     /* HFP */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              HORIZON_FRONT_PORCH_L_7E,
> > +                              ctx->dt.hfront_porch.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              HORIZON_FRONT_PORCH_H_7E,
> > +                              ctx->dt.hfront_porch.min >> 8);
> > +     /* HWS */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              HORIZON_SYNC_WIDTH_L_7E,
> > +                              ctx->dt.hsync_len.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              HORIZON_SYNC_WIDTH_H_7E,
> > +                              ctx->dt.hsync_len.min >> 8);
> > +     /* HBP */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              HORIZON_BACK_PORCH_L_7E,
> > +                              ctx->dt.hback_porch.min);
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > +                              HORIZON_BACK_PORCH_H_7E,
> > +                              ctx->dt.hback_porch.min >> 8);
> > +
> > +     /* Config DSC decoder internal blank timing for decoder to start */
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > +                              H_BLANK_L,
> > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > +                              H_BLANK_H,
> > +                              dsc_div(htotal - ctx->dt.hactive.min)
> > + >> 8);
> > +
> > +     /* Compress ratio  RATIO bit[7:6] */
> > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
> > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > +     /*PPS table*/
> > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > +                                            R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > +                                            &ctx->pps_table[i]);
> > +
> > +     return ret;
> > +}
> > +
> > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > +                             struct i2c_client *client,
> > +                             u8 reg_addr, u16 reg_val, bool
> > +high_byte) {
> > +     u8 reg_data;
> > +
> > +     if (ctx->dsc_en)
> > +             reg_val = dsc_div(reg_val);
> > +
> > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) & 0xFF;
> > +
> > +     return anx7625_reg_write(ctx, client, reg_addr, reg_data); }
> 
> Ugh, no. Calculate htotal in the calling function and call
> anx7625_reg_write() as you were doing that before.
> 
anx7625_timing_write() is a common function, it was called many times,
so we cannot calculate htotal in it.

> > +
> >  static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
> > {
> >       struct device *dev = ctx->dev;
> > @@ -506,34 +639,33 @@ static int anx7625_dsi_video_timing_config(struct
> anx7625_data *ctx)
> >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> >                               MIPI_LANE_CTRL_0, ctx->pdata.mipi_lanes
> > - 1);
> >
> > -     /* Htotal */
> >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > +     /* Htotal */
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal, true);
> >       /* Hactive */
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min, false);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min,
> > + true);
> >       /* HFP */
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_FRONT_PORCH_H,
> > -                     ctx->dt.hfront_porch.min >> 8);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min, false);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_FRONT_PORCH_H,
> > + ctx->dt.hfront_porch.min, true);
> 
> Are porches also compressed? I think blanking signal timings are transferred as is,
> without compression.
Porches not be compressed, anx7625 internal digital block will multiply by 3 while enable
DSC feature, so the register must divided by 3.
> 
> >       /* HWS */
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min, false);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min,
> > + true);
> >       /* HBP */
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > -                     HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min, false);
> > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > +                     HORIZONTAL_BACK_PORCH_H,
> > + ctx->dt.hback_porch.min, true);
> >       /* Vactive */
> >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
> >                       ctx->dt.vactive.min); @@ -663,9 +795,15 @@
> > static int anx7625_dsi_config(struct anx7625_data *ctx)
> >
> >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> >
> > -     /* DSC disable */
> > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > -                             R_DSC_CTRL_0, ~DSC_EN);
> > +     ret = anx7625_set_dsc_params(ctx);
> > +     if (ctx->dsc_en)
> > +             /* DSC enable */
> > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > +                                     R_DSC_CTRL_0, DSC_EN);
> > +     else
> > +             /* DSC disable */
> > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > +                                      R_DSC_CTRL_0, ~DSC_EN);
> >
> >       ret |= anx7625_api_dsi_config(ctx);
> >
> > @@ -2083,6 +2221,7 @@ static int anx7625_setup_dsi_device(struct
> anx7625_data *ctx)
> >               MIPI_DSI_MODE_VIDEO_HSE |
> >               MIPI_DSI_HS_PKT_END_ALIGNED;
> >
> > +     dsi->dsc = &ctx->dsc;
> >       ctx->dsi = dsi;
> >
> >       return 0;
> > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct drm_bridge
> *bridge,
> >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> >       struct device *dev = ctx->dev;
> >
> > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > +     dev_dbg(dev, "drm mode checking\n");
> > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > +             return MODE_CLOCK_HIGH;
> > +
> > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > +             return MODE_CLOCK_LOW;
> >
> > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > -             DRM_DEV_DEBUG_DRIVER(dev,
> > -                                  "drm mode invalid, pixelclock too high.\n");
> > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3 != 0))
> 
> Magic number 3. Also is it actually required? I think DSC standard has no such
> requirement.
This is anx7625 limitation, if mode->hdisplay cannot be divided by 3, then display will have
overlap/shift issue.
> 
> >               return MODE_CLOCK_HIGH;
> > -     }
> >
> > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > +     dev_dbg(dev, "drm mode valid.\n");
> >
> >       return MODE_OK;
> >  }
> >
> > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > +     int ret;
> > +     struct device *dev = ctx->dev;
> > +
> > +     ctx->dsc_en = en;
> > +
> > +     if (en) {
> > +             ctx->dsc.dsc_version_major = 1;
> > +             ctx->dsc.dsc_version_minor = 1;
> > +             ctx->dsc.slice_height = 8;
> > +             ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > +             ctx->dsc.bits_per_component = 8;
> > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > +             ctx->dsc.block_pred_enable = true;
> > +             ctx->dsc.native_420 = false;
> > +             ctx->dsc.native_422 = false;
> > +             ctx->dsc.simple_422 = false;
> > +             ctx->dsc.vbr_enable = false;
> > +             ctx->dsc.rc_model_size = DSC_RC_MODEL_SIZE_CONST;
> > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > +             ctx->dsc.pic_height = ctx->dt.vactive.min;
> > +             ctx->dsc.convert_rgb = 1;
> > +             ctx->dsc.vbr_enable = 0;
> 
> A lot of this params should be coming from the sink device. You have to get
> them from the DPCD.
These parameter is just MIPI source and anx7625 and used only for DSC feature,
Anx7625 is bridge IC, sink monitor only receive normal DP signal from anx7625,
sink device didn't know DSC information, no need read DPCD.
> 
> > +
> > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > +             drm_dsc_set_const_params(&ctx->dsc);
> > +
> > +             ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx->dsc);
> > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > +             ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
> > +             if (ret < 0)
> > +                     dev_warn(dev, "drm_dsc_setup_rc_params ret
> > + %d\n", ret);
> > +
> > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> 
> You have ignored return value. Please handle the function returning an error.
OK
> 
> > +
> > +             drm_dsc_pps_payload_pack((struct drm_dsc_picture_parameter_set
> *)&ctx->pps_table,
> > +                                      &ctx->dsc);
> > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > +     } else {
> > +             ctx->dsc.dsc_version_major = 0;
> > +             ctx->dsc.dsc_version_minor = 0;
> > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > +     }
> > +}
> > +
> >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> >                                   const struct drm_display_mode *old_mode,
> >                                   const struct drm_display_mode *mode)
> > @@ -2244,6 +2431,11 @@ static void anx7625_bridge_mode_set(struct
> drm_bridge *bridge,
> >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> >                            mode->vsync_end,
> >                            mode->vtotal);
> > +
> > +     if (mode->clock > DSC_PIXEL_CLOCK)
> 
> What if the sink doesn't support DSC? The decision whether to enable DSC or not
> should be happening in the atomic_check(). Likewise mode_valid should be able
> to check if your bridge and the sink can agree on DSC params and reject modes if
> they can not.
Anx7625 is bridge IC, it receive MIPI data and DP output, DSC only exist between SOC
and Anx7625, sink monitor only receive normal DP signal from anx7625,
there is no compression at DP output, so no need to check sink device.
> 
> > +             anx7625_dsc_enable(ctx, true);
> > +     else
> > +             anx7625_dsc_enable(ctx, false);
> >  }
> >
> >  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge, @@
> > -2258,26 +2450,33 @@ static bool anx7625_bridge_mode_fixup(struct
> > drm_bridge *bridge,
> >
> >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> >
> > -     /* No need fixup for external monitor */
> > -     if (!ctx->pdata.panel_bridge)
> > -             return true;
> > -
> >       hsync = mode->hsync_end - mode->hsync_start;
> >       hfp = mode->hsync_start - mode->hdisplay;
> >       hbp = mode->htotal - mode->hsync_end;
> >       hblanking = mode->htotal - mode->hdisplay;
> >
> > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> clock(%d)\n",
> > -                          hsync, hfp, hbp, adj->clock);
> > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> htot(%d)\n",
> > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > -
> > +     dev_dbg(dev, "before mode fixup\n");
> > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > +             hsync, hfp, hbp, adj->clock);
> > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > +             adj->hsync_start, adj->hsync_end, adj->htotal);
> 
> No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway, this should go
> to a separate commit.
OK, I'll not change it in this patch.
> 
> >       adj_hfp = hfp;
> >       adj_hsync = hsync;
> >       adj_hbp = hbp;
> >       adj_hblanking = hblanking;
> >
> > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > +             adj_hsync = DSC_HSYNC_LEN;
> > +             adj_hfp = DSC_HFP_LEN;
> > +             adj_hbp = DSC_HBP_LEN;
> > +             vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
> > +             goto calculate_timing;
> > +     }
> > +
> > +     /* No need fixup for external monitor */
> > +     if (!ctx->pdata.panel_bridge)
> > +             return true;
> > +
> >       /* HFP needs to be even */
> >       if (hfp & 0x1) {
> >               adj_hfp += 1;
> > @@ -2349,16 +2548,21 @@ static bool anx7625_bridge_mode_fixup(struct
> drm_bridge *bridge,
> >                       adj_hfp -= delta_adj;
> >       }
> >
> > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> clock(%d)\n",
> > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > +calculate_timing:
> > +
> > +     dev_dbg(dev, "after mode fixup\n");
> > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> >
> >       /* Reconstruct timing */
> >       adj->hsync_start = adj->hdisplay + adj_hfp;
> >       adj->hsync_end = adj->hsync_start + adj_hsync;
> >       adj->htotal = adj->hsync_end + adj_hbp;
> > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> htot(%d)\n",
> > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > +             adj->clock = (u64)vref * adj->htotal * adj->vtotal /
> > + 1000 / 1000;
> > +
> > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
> > +             adj->hsync_start, adj->hsync_end, adj->htotal,
> > + adj->clock);
> >
> >       return true;
> >  }
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > index eb5580f1ab2f..db931f5800b1 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > @@ -149,6 +149,8 @@
> >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
> >  #define VIDEO_CONTROL_0      0x08
> >
> > +#define  TOTAL_LINES_L          0x12
> > +#define  TOTAL_LINES_H          0x13
> >  #define  ACTIVE_LINES_L         0x14
> >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> >  #define  VERTICAL_FRONT_PORCH   0x16
> > @@ -166,6 +168,32 @@
> >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are reserved */
> >
> > +#define  H_BLANK_L                    0x3E
> > +#define  H_BLANK_H                    0x3F
> > +#define  DSC_COMPRESS_RATIO           3
> > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> 
> This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode? Or does
> 1:3 come from some other ratio?
We only tested 1:3 compression ratio, 24bpp compress to 8bpp.
> 
> > +#define  DSC_SLICE_NUM                2
> > +#define  DSC_PIXEL_CLOCK              250000
> > +#define  DSC_HSYNC_LEN                90
> > +#define  DSC_HFP_LEN                  177
> > +#define  DSC_HBP_LEN                  297
> > +
> > +#define  TOTAL_PIXEL_L_7E             0x50
> > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> > +#define  ACTIVE_PIXEL_L_7E            0x52
> > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > +
> > +#define  PPS_SIZE                     128
> > +#define  PPS_BLOCK_SIZE               32
> > +#define  R_PPS_REG_0                  0x80
> > +#define  R_I2C_1                      0x81
> > +
> >  /******** END of I2C Address 0x72 *********/
> >
> >
> /***************************************************************/
> > @@ -415,6 +443,7 @@ enum audio_wd_len {
> >  #define MAX_EDID_BLOCK       3
> >  #define EDID_TRY_CNT 3
> >  #define SUPPORT_PIXEL_CLOCK  300000
> > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> >
> >  /***************** Display End *****************/
> >
> > @@ -454,6 +483,7 @@ struct anx7625_data {
> >       int hpd_high_cnt;
> >       int dp_en;
> >       int hdcp_cp;
> > +     bool dsc_en;
> >       /* Lock for work queue */
> >       struct mutex lock;
> >       struct device *dev;
> > @@ -479,6 +509,8 @@ struct anx7625_data {
> >       struct drm_connector *connector;
> >       struct mipi_dsi_device *dsi;
> >       struct drm_dp_aux aux;
> > +     struct drm_dsc_config dsc;
> > +     char pps_table[PPS_SIZE];
> 
> pps_table and drm_dsc_config can vary depending on the mode and connected
> sink. THey should be a part of the atomic state rather than a long-living
> anx7625_data. So does dsc_en.
No need to check sink monitor, because DSC only exist between SOC and Anx7625,
sink monitor only receive normal DP signal from anx7625. Anx7625 is responsible for
decompression.
> 
> >  };
> >
> >  #endif  /* __ANX7625_H__ */
> > --
> > 2.25.1
> >
> 
> --
> With best wishes
> Dmitry
Dmitry Baryshkov Feb. 14, 2025, 11:46 a.m. UTC | #3
On Fri, Feb 14, 2025 at 11:20:01AM +0000, Xin Ji wrote:
> > -----Original Message-----
> > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > Sent: Thursday, February 13, 2025 9:04 PM
> > To: Xin Ji <xji@analogixsemi.com>
> > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent Pinchart
> > <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>;
> > Jernej Skrabec <jernej.skrabec@gmail.com>; Maarten Lankhorst
> > <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>;
> > Thomas Zimmermann <tzimmermann@suse.de>; David Airlie
> > <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Bernie Liang
> > <bliang@analogixsemi.com>; Qilin Wen <qwen@analogixsemi.com>;
> > treapking@google.com; dri-devel@lists.freedesktop.org; linux-
> > kernel@vger.kernel.org
> > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature

PLease remove such splats, use something more sensible.

> > 
> > 
> > On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and internal
> > > pixel clock(maximum 300M) limitation. Anx7625 must enable DSC feature
> > > while MIPI source want to output 4K30 resolution.
> > 
> > This commit message is pretty hard to read and understand for a non-native
> > speaker. Please consider rewriting it so that it is easier to understand it.
> > 
> Thanks for the review, sorry about that, I'll rewriting the commit message
> > >
> > > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > > ---
> > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > > ++++++++++++++++++----  drivers/gpu/drm/bridge/analogix/anx7625.h |
> > > 32 +++
> > >  2 files changed, 284 insertions(+), 48 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > index 4be34d5c7a3b..7d86ab02f71c 100644
> > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > @@ -22,6 +22,7 @@
> > >
> > >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > > <drm/display/drm_dp_helper.h>
> > > +#include <drm/display/drm_dsc_helper.h>
> > >  #include <drm/display/drm_hdcp_helper.h>  #include
> > > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@ -476,6
> > > +477,138 @@ static int anx7625_set_k_value(struct anx7625_data *ctx)
> > >                                MIPI_DIGITAL_ADJ_1, 0x3D);  }
> > >
> > > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > > +     int ret, i;
> > > +     u16 htotal, vtotal;
> > > +
> > > +     if (!ctx->dsc_en)
> > > +             return 0;
> > > +
> > > +     /* Htotal */
> > > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > +     /* Hactive */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > > +                              ctx->dt.hactive.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > > +                              ctx->dt.hactive.min >> 8);
> > > +     /* HFP */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_FRONT_PORCH_L,
> > > +                              ctx->dt.hfront_porch.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_FRONT_PORCH_H,
> > > +                              ctx->dt.hfront_porch.min >> 8);
> > > +     /* HWS */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_SYNC_WIDTH_L,
> > > +                              ctx->dt.hsync_len.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_SYNC_WIDTH_H,
> > > +                              ctx->dt.hsync_len.min >> 8);
> > > +     /* HBP */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_BACK_PORCH_L,
> > > +                              ctx->dt.hback_porch.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              HORIZONTAL_BACK_PORCH_H,
> > > +                              ctx->dt.hback_porch.min >> 8);
> > > +     /* Vtotal */
> > > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
> > > +                              vtotal);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
> > > +                              vtotal >> 8);
> > > +     /* Vactive */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_L,
> > > +                              ctx->dt.vactive.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_H,
> > > +                              ctx->dt.vactive.min >> 8);
> > > +     /* VFP */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > > +     /* VWS */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > > +     /* VBP */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > +                              VERTICAL_BACK_PORCH,
> > > + ctx->dt.vback_porch.min);
> > 
> > This code mostly duplicates anx7625_dsi_video_timing_config() with the I2C
> > client being the only difference. Please consider extracting a common helper to
> > write the timings.
> It is hard to extracting a common helper, they are used different I2C slave address
> and timing register need divided by 3 if DSC enabled.

I2C client can be a parameter. Also please comment whether /3 is because
of bpp/bpc ratio or due to some other reason?

Does anx7625 support any mode other than 8bpp / 8bpc?

> > 
> > > +
> > > +     /* Htotal */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_L_7E,
> > > +                              htotal);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_H_7E,
> > > +                              htotal >> 8);
> > > +     /* Hactive */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > > +     /* HFP */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              HORIZON_FRONT_PORCH_L_7E,
> > > +                              ctx->dt.hfront_porch.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              HORIZON_FRONT_PORCH_H_7E,
> > > +                              ctx->dt.hfront_porch.min >> 8);
> > > +     /* HWS */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              HORIZON_SYNC_WIDTH_L_7E,
> > > +                              ctx->dt.hsync_len.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              HORIZON_SYNC_WIDTH_H_7E,
> > > +                              ctx->dt.hsync_len.min >> 8);
> > > +     /* HBP */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              HORIZON_BACK_PORCH_L_7E,
> > > +                              ctx->dt.hback_porch.min);
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > +                              HORIZON_BACK_PORCH_H_7E,
> > > +                              ctx->dt.hback_porch.min >> 8);
> > > +
> > > +     /* Config DSC decoder internal blank timing for decoder to start */
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > +                              H_BLANK_L,
> > > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > +                              H_BLANK_H,
> > > +                              dsc_div(htotal - ctx->dt.hactive.min)
> > > + >> 8);
> > > +
> > > +     /* Compress ratio  RATIO bit[7:6] */
> > > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
> > > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > > +     /*PPS table*/
> > > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > > +                                            R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > > +                                            &ctx->pps_table[i]);
> > > +
> > > +     return ret;
> > > +}
> > > +
> > > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > > +                             struct i2c_client *client,
> > > +                             u8 reg_addr, u16 reg_val, bool
> > > +high_byte) {
> > > +     u8 reg_data;
> > > +
> > > +     if (ctx->dsc_en)
> > > +             reg_val = dsc_div(reg_val);
> > > +
> > > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) & 0xFF;
> > > +
> > > +     return anx7625_reg_write(ctx, client, reg_addr, reg_data); }
> > 
> > Ugh, no. Calculate htotal in the calling function and call
> > anx7625_reg_write() as you were doing that before.
> > 
> anx7625_timing_write() is a common function, it was called many times,
> so we cannot calculate htotal in it.

On the caller side. I'd suggest to inline anx7625_timing_write() to make
the code more explicit.

> 
> > > +
> > >  static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
> > > {
> > >       struct device *dev = ctx->dev;
> > > @@ -506,34 +639,33 @@ static int anx7625_dsi_video_timing_config(struct
> > anx7625_data *ctx)
> > >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > >                               MIPI_LANE_CTRL_0, ctx->pdata.mipi_lanes
> > > - 1);
> > >
> > > -     /* Htotal */
> > >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > +     /* Htotal */
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal, true);
> > >       /* Hactive */
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min, false);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min,
> > > + true);
> > >       /* HFP */
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_FRONT_PORCH_H,
> > > -                     ctx->dt.hfront_porch.min >> 8);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min, false);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_FRONT_PORCH_H,
> > > + ctx->dt.hfront_porch.min, true);
> > 
> > Are porches also compressed? I think blanking signal timings are transferred as is,
> > without compression.
> Porches not be compressed, anx7625 internal digital block will multiply by 3 while enable
> DSC feature, so the register must divided by 3.

Ack

> > 
> > >       /* HWS */
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min, false);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min,
> > > + true);
> > >       /* HBP */
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > -                     HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min, false);
> > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > +                     HORIZONTAL_BACK_PORCH_H,
> > > + ctx->dt.hback_porch.min, true);
> > >       /* Vactive */
> > >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
> > >                       ctx->dt.vactive.min); @@ -663,9 +795,15 @@
> > > static int anx7625_dsi_config(struct anx7625_data *ctx)
> > >
> > >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> > >
> > > -     /* DSC disable */
> > > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > -                             R_DSC_CTRL_0, ~DSC_EN);
> > > +     ret = anx7625_set_dsc_params(ctx);
> > > +     if (ctx->dsc_en)
> > > +             /* DSC enable */
> > > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > > +                                     R_DSC_CTRL_0, DSC_EN);
> > > +     else
> > > +             /* DSC disable */
> > > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > +                                      R_DSC_CTRL_0, ~DSC_EN);
> > >
> > >       ret |= anx7625_api_dsi_config(ctx);
> > >
> > > @@ -2083,6 +2221,7 @@ static int anx7625_setup_dsi_device(struct
> > anx7625_data *ctx)
> > >               MIPI_DSI_MODE_VIDEO_HSE |
> > >               MIPI_DSI_HS_PKT_END_ALIGNED;
> > >
> > > +     dsi->dsc = &ctx->dsc;
> > >       ctx->dsi = dsi;
> > >
> > >       return 0;
> > > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct drm_bridge
> > *bridge,
> > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > >       struct device *dev = ctx->dev;
> > >
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > > +     dev_dbg(dev, "drm mode checking\n");
> > > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > > +             return MODE_CLOCK_HIGH;
> > > +
> > > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > > +             return MODE_CLOCK_LOW;
> > >
> > > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > > -             DRM_DEV_DEBUG_DRIVER(dev,
> > > -                                  "drm mode invalid, pixelclock too high.\n");
> > > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3 != 0))
> > 
> > Magic number 3. Also is it actually required? I think DSC standard has no such
> > requirement.
> This is anx7625 limitation, if mode->hdisplay cannot be divided by 3, then display will have
> overlap/shift issue.

Ack, add a comment or extend a commit message please.

> > 
> > >               return MODE_CLOCK_HIGH;
> > > -     }
> > >
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > > +     dev_dbg(dev, "drm mode valid.\n");
> > >
> > >       return MODE_OK;
> > >  }
> > >
> > > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > > +     int ret;
> > > +     struct device *dev = ctx->dev;
> > > +
> > > +     ctx->dsc_en = en;
> > > +
> > > +     if (en) {
> > > +             ctx->dsc.dsc_version_major = 1;
> > > +             ctx->dsc.dsc_version_minor = 1;
> > > +             ctx->dsc.slice_height = 8;
> > > +             ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > > +             ctx->dsc.bits_per_component = 8;
> > > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > > +             ctx->dsc.block_pred_enable = true;
> > > +             ctx->dsc.native_420 = false;
> > > +             ctx->dsc.native_422 = false;
> > > +             ctx->dsc.simple_422 = false;
> > > +             ctx->dsc.vbr_enable = false;
> > > +             ctx->dsc.rc_model_size = DSC_RC_MODEL_SIZE_CONST;

This one is default, please drop.

> > > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > > +             ctx->dsc.pic_height = ctx->dt.vactive.min;

These two are set on the DSC encoder side.

> > > +             ctx->dsc.convert_rgb = 1;
> > > +             ctx->dsc.vbr_enable = 0;
> > 
> > A lot of this params should be coming from the sink device. You have to get
> > them from the DPCD.
> These parameter is just MIPI source and anx7625 and used only for DSC feature,
> Anx7625 is bridge IC, sink monitor only receive normal DP signal from anx7625,
> sink device didn't know DSC information, no need read DPCD.

Thanks. From you commit message it is impossible to understand whether
DSC happens between the host and your bridge or between the bridge and
the monitor.

> > 
> > > +
> > > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > > +             drm_dsc_set_const_params(&ctx->dsc);
> > > +
> > > +             ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx->dsc);
> > > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > > +             ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
> > > +             if (ret < 0)
> > > +                     dev_warn(dev, "drm_dsc_setup_rc_params ret
> > > + %d\n", ret);
> > > +
> > > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> > 
> > You have ignored return value. Please handle the function returning an error.
> OK

All these functions are to be called on the DSC encoder side as it has
to be able to infer DSC params.

> > 
> > > +
> > > +             drm_dsc_pps_payload_pack((struct drm_dsc_picture_parameter_set
> > *)&ctx->pps_table,
> > > +                                      &ctx->dsc);
> > > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > > +     } else {
> > > +             ctx->dsc.dsc_version_major = 0;
> > > +             ctx->dsc.dsc_version_minor = 0;
> > > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > > +     }
> > > +}
> > > +
> > >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > >                                   const struct drm_display_mode *old_mode,
> > >                                   const struct drm_display_mode *mode)
> > > @@ -2244,6 +2431,11 @@ static void anx7625_bridge_mode_set(struct
> > drm_bridge *bridge,
> > >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > >                            mode->vsync_end,
> > >                            mode->vtotal);
> > > +
> > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > 
> > What if the sink doesn't support DSC? The decision whether to enable DSC or not
> > should be happening in the atomic_check(). Likewise mode_valid should be able
> > to check if your bridge and the sink can agree on DSC params and reject modes if
> > they can not.
> Anx7625 is bridge IC, it receive MIPI data and DP output, DSC only exist between SOC
> and Anx7625, sink monitor only receive normal DP signal from anx7625,
> there is no compression at DP output, so no need to check sink device.

Well. Then the same question applies in the other direction: what if the
host doesnt' support DSC?

> > 
> > > +             anx7625_dsc_enable(ctx, true);
> > > +     else
> > > +             anx7625_dsc_enable(ctx, false);
> > >  }
> > >
> > >  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge, @@
> > > -2258,26 +2450,33 @@ static bool anx7625_bridge_mode_fixup(struct
> > > drm_bridge *bridge,
> > >
> > >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> > >
> > > -     /* No need fixup for external monitor */
> > > -     if (!ctx->pdata.panel_bridge)
> > > -             return true;
> > > -
> > >       hsync = mode->hsync_end - mode->hsync_start;
> > >       hfp = mode->hsync_start - mode->hdisplay;
> > >       hbp = mode->htotal - mode->hsync_end;
> > >       hblanking = mode->htotal - mode->hdisplay;
> > >
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > clock(%d)\n",
> > > -                          hsync, hfp, hbp, adj->clock);
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > htot(%d)\n",
> > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > -
> > > +     dev_dbg(dev, "before mode fixup\n");
> > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > +             hsync, hfp, hbp, adj->clock);
> > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > > +             adj->hsync_start, adj->hsync_end, adj->htotal);
> > 
> > No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway, this should go
> > to a separate commit.
> OK, I'll not change it in this patch.
> > 
> > >       adj_hfp = hfp;
> > >       adj_hsync = hsync;
> > >       adj_hbp = hbp;
> > >       adj_hblanking = hblanking;
> > >
> > > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > > +             adj_hsync = DSC_HSYNC_LEN;
> > > +             adj_hfp = DSC_HFP_LEN;
> > > +             adj_hbp = DSC_HBP_LEN;
> > > +             vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
> > > +             goto calculate_timing;
> > > +     }
> > > +
> > > +     /* No need fixup for external monitor */
> > > +     if (!ctx->pdata.panel_bridge)
> > > +             return true;
> > > +
> > >       /* HFP needs to be even */
> > >       if (hfp & 0x1) {
> > >               adj_hfp += 1;
> > > @@ -2349,16 +2548,21 @@ static bool anx7625_bridge_mode_fixup(struct
> > drm_bridge *bridge,
> > >                       adj_hfp -= delta_adj;
> > >       }
> > >
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > clock(%d)\n",
> > > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > +calculate_timing:
> > > +
> > > +     dev_dbg(dev, "after mode fixup\n");
> > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > >
> > >       /* Reconstruct timing */
> > >       adj->hsync_start = adj->hdisplay + adj_hfp;
> > >       adj->hsync_end = adj->hsync_start + adj_hsync;
> > >       adj->htotal = adj->hsync_end + adj_hbp;
> > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > htot(%d)\n",
> > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > +             adj->clock = (u64)vref * adj->htotal * adj->vtotal /
> > > + 1000 / 1000;
> > > +
> > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
> > > +             adj->hsync_start, adj->hsync_end, adj->htotal,
> > > + adj->clock);
> > >
> > >       return true;
> > >  }
> > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > index eb5580f1ab2f..db931f5800b1 100644
> > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > @@ -149,6 +149,8 @@
> > >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
> > >  #define VIDEO_CONTROL_0      0x08
> > >
> > > +#define  TOTAL_LINES_L          0x12
> > > +#define  TOTAL_LINES_H          0x13
> > >  #define  ACTIVE_LINES_L         0x14
> > >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> > >  #define  VERTICAL_FRONT_PORCH   0x16
> > > @@ -166,6 +168,32 @@
> > >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> > >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are reserved */
> > >
> > > +#define  H_BLANK_L                    0x3E
> > > +#define  H_BLANK_H                    0x3F
> > > +#define  DSC_COMPRESS_RATIO           3
> > > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> > 
> > This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode? Or does
> > 1:3 come from some other ratio?
> We only tested 1:3 compression ratio, 24bpp compress to 8bpp.

What are hardware limitations?

> > 
> > > +#define  DSC_SLICE_NUM                2
> > > +#define  DSC_PIXEL_CLOCK              250000
> > > +#define  DSC_HSYNC_LEN                90
> > > +#define  DSC_HFP_LEN                  177
> > > +#define  DSC_HBP_LEN                  297
> > > +
> > > +#define  TOTAL_PIXEL_L_7E             0x50
> > > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> > > +#define  ACTIVE_PIXEL_L_7E            0x52
> > > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> > > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > > +
> > > +#define  PPS_SIZE                     128
> > > +#define  PPS_BLOCK_SIZE               32
> > > +#define  R_PPS_REG_0                  0x80
> > > +#define  R_I2C_1                      0x81
> > > +
> > >  /******** END of I2C Address 0x72 *********/
> > >
> > >
> > /***************************************************************/
> > > @@ -415,6 +443,7 @@ enum audio_wd_len {
> > >  #define MAX_EDID_BLOCK       3
> > >  #define EDID_TRY_CNT 3
> > >  #define SUPPORT_PIXEL_CLOCK  300000
> > > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> > >
> > >  /***************** Display End *****************/
> > >
> > > @@ -454,6 +483,7 @@ struct anx7625_data {
> > >       int hpd_high_cnt;
> > >       int dp_en;
> > >       int hdcp_cp;
> > > +     bool dsc_en;
> > >       /* Lock for work queue */
> > >       struct mutex lock;
> > >       struct device *dev;
> > > @@ -479,6 +509,8 @@ struct anx7625_data {
> > >       struct drm_connector *connector;
> > >       struct mipi_dsi_device *dsi;
> > >       struct drm_dp_aux aux;
> > > +     struct drm_dsc_config dsc;
> > > +     char pps_table[PPS_SIZE];
> > 
> > pps_table and drm_dsc_config can vary depending on the mode and connected
> > sink. THey should be a part of the atomic state rather than a long-living
> > anx7625_data. So does dsc_en.
> No need to check sink monitor, because DSC only exist between SOC and Anx7625,
> sink monitor only receive normal DP signal from anx7625. Anx7625 is responsible for
> decompression.

The same way, they depend on the selected video mode, don't they?

> > 
> > >  };
> > >
> > >  #endif  /* __ANX7625_H__ */
> > > --
> > > 2.25.1
> > >
> > 
> > --
> > With best wishes
> > Dmitry
Xin Ji Feb. 14, 2025, 1:05 p.m. UTC | #4
> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Sent: Friday, February 14, 2025 7:47 PM
> To: Xin Ji <xji@analogixsemi.com>
> Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent Pinchart
> <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>;
> Jernej Skrabec <jernej.skrabec@gmail.com>; Maarten Lankhorst
> <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>;
> Thomas Zimmermann <tzimmermann@suse.de>; David Airlie
> <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Bernie Liang
> <bliang@analogixsemi.com>; Qilin Wen <qwen@analogixsemi.com>;
> treapking@google.com; dri-devel@lists.freedesktop.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> 
> 
> On Fri, Feb 14, 2025 at 11:20:01AM +0000, Xin Ji wrote:
> > > -----Original Message-----
> > > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > Sent: Thursday, February 13, 2025 9:04 PM
> > > To: Xin Ji <xji@analogixsemi.com>
> > > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent
> > > Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas Karlman
> > > <jonas@kwiboo.se>; Jernej Skrabec <jernej.skrabec@gmail.com>;
> > > Maarten Lankhorst <maarten.lankhorst@linux.intel.com>; Maxime Ripard
> > > <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>;
> David
> > > Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Bernie
> > > Liang <bliang@analogixsemi.com>; Qilin Wen <qwen@analogixsemi.com>;
> > > treapking@google.com; dri-devel@lists.freedesktop.org; linux-
> > > kernel@vger.kernel.org
> > > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> 
> PLease remove such splats, use something more sensible.
OK, I'll change the subject
> 
> > >
> > >
> > > On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > > > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and
> > > > internal pixel clock(maximum 300M) limitation. Anx7625 must enable
> > > > DSC feature while MIPI source want to output 4K30 resolution.
> > >
> > > This commit message is pretty hard to read and understand for a
> > > non-native speaker. Please consider rewriting it so that it is easier to
> understand it.
> > >
> > Thanks for the review, sorry about that, I'll rewriting the commit
> > message
> > > >
> > > > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > > > ---
> > > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > > > ++++++++++++++++++----  drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > ++++++++++++++++++|
> > > > 32 +++
> > > >  2 files changed, 284 insertions(+), 48 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > index 4be34d5c7a3b..7d86ab02f71c 100644
> > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > @@ -22,6 +22,7 @@
> > > >
> > > >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > > > <drm/display/drm_dp_helper.h>
> > > > +#include <drm/display/drm_dsc_helper.h>
> > > >  #include <drm/display/drm_hdcp_helper.h>  #include
> > > > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@ -476,6
> > > > +477,138 @@ static int anx7625_set_k_value(struct anx7625_data
> > > > +*ctx)
> > > >                                MIPI_DIGITAL_ADJ_1, 0x3D);  }
> > > >
> > > > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > > > +     int ret, i;
> > > > +     u16 htotal, vtotal;
> > > > +
> > > > +     if (!ctx->dsc_en)
> > > > +             return 0;
> > > > +
> > > > +     /* Htotal */
> > > > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > +     /* Hactive */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > > > +                              ctx->dt.hactive.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > > > +                              ctx->dt.hactive.min >> 8);
> > > > +     /* HFP */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_FRONT_PORCH_L,
> > > > +                              ctx->dt.hfront_porch.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_FRONT_PORCH_H,
> > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > +     /* HWS */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_SYNC_WIDTH_L,
> > > > +                              ctx->dt.hsync_len.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_SYNC_WIDTH_H,
> > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > +     /* HBP */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_BACK_PORCH_L,
> > > > +                              ctx->dt.hback_porch.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              HORIZONTAL_BACK_PORCH_H,
> > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > +     /* Vtotal */
> > > > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > > > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
> > > > +                              vtotal);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
> > > > +                              vtotal >> 8);
> > > > +     /* Vactive */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_L,
> > > > +                              ctx->dt.vactive.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_H,
> > > > +                              ctx->dt.vactive.min >> 8);
> > > > +     /* VFP */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > > > +     /* VWS */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > > > +     /* VBP */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > +                              VERTICAL_BACK_PORCH,
> > > > + ctx->dt.vback_porch.min);
> > >
> > > This code mostly duplicates anx7625_dsi_video_timing_config() with
> > > the I2C client being the only difference. Please consider extracting
> > > a common helper to write the timings.
> > It is hard to extracting a common helper, they are used different I2C
> > slave address and timing register need divided by 3 if DSC enabled.
> 
> I2C client can be a parameter. Also please comment whether /3 is because of
> bpp/bpc ratio or due to some other reason?
> 
> Does anx7625 support any mode other than 8bpp / 8bpc?
I'll try to make a common function, anx7625 mipi only support RGB888. DSC 8bpp.
/3 is because of DSC ration 1:3.
> 
> > >
> > > > +
> > > > +     /* Htotal */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> TOTAL_PIXEL_L_7E,
> > > > +                              htotal);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> TOTAL_PIXEL_H_7E,
> > > > +                              htotal >> 8);
> > > > +     /* Hactive */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > > > +     /* HFP */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              HORIZON_FRONT_PORCH_L_7E,
> > > > +                              ctx->dt.hfront_porch.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              HORIZON_FRONT_PORCH_H_7E,
> > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > +     /* HWS */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              HORIZON_SYNC_WIDTH_L_7E,
> > > > +                              ctx->dt.hsync_len.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              HORIZON_SYNC_WIDTH_H_7E,
> > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > +     /* HBP */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              HORIZON_BACK_PORCH_L_7E,
> > > > +                              ctx->dt.hback_porch.min);
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > +                              HORIZON_BACK_PORCH_H_7E,
> > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > +
> > > > +     /* Config DSC decoder internal blank timing for decoder to start */
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > +                              H_BLANK_L,
> > > > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > +                              H_BLANK_H,
> > > > +                              dsc_div(htotal -
> > > > + ctx->dt.hactive.min)
> > > > + >> 8);
> > > > +
> > > > +     /* Compress ratio  RATIO bit[7:6] */
> > > > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
> > > > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > > > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > > > +     /*PPS table*/
> > > > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > > > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                                            R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > > > +                                            &ctx->pps_table[i]);
> > > > +
> > > > +     return ret;
> > > > +}
> > > > +
> > > > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > > > +                             struct i2c_client *client,
> > > > +                             u8 reg_addr, u16 reg_val, bool
> > > > +high_byte) {
> > > > +     u8 reg_data;
> > > > +
> > > > +     if (ctx->dsc_en)
> > > > +             reg_val = dsc_div(reg_val);
> > > > +
> > > > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) & 0xFF;
> > > > +
> > > > +     return anx7625_reg_write(ctx, client, reg_addr, reg_data); }
> > >
> > > Ugh, no. Calculate htotal in the calling function and call
> > > anx7625_reg_write() as you were doing that before.
> > >
> > anx7625_timing_write() is a common function, it was called many times,
> > so we cannot calculate htotal in it.
> 
> On the caller side. I'd suggest to inline anx7625_timing_write() to make the code
> more explicit.
OK.
> 
> >
> > > > +
> > > >  static int anx7625_dsi_video_timing_config(struct anx7625_data
> > > > *ctx) {
> > > >       struct device *dev = ctx->dev; @@ -506,34 +639,33 @@ static
> > > > int anx7625_dsi_video_timing_config(struct
> > > anx7625_data *ctx)
> > > >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > > >                               MIPI_LANE_CTRL_0,
> > > > ctx->pdata.mipi_lanes
> > > > - 1);
> > > >
> > > > -     /* Htotal */
> > > >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > +     /* Htotal */
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal, true);
> > > >       /* Hactive */
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min, false);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_ACTIVE_PIXELS_H,
> > > > + ctx->dt.hactive.min, true);
> > > >       /* HFP */
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_FRONT_PORCH_H,
> > > > -                     ctx->dt.hfront_porch.min >> 8);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min,
> false);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_FRONT_PORCH_H,
> > > > + ctx->dt.hfront_porch.min, true);
> > >
> > > Are porches also compressed? I think blanking signal timings are
> > > transferred as is, without compression.
> > Porches not be compressed, anx7625 internal digital block will
> > multiply by 3 while enable DSC feature, so the register must divided by 3.
> 
> Ack
> 
> > >
> > > >       /* HWS */
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min, false);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_SYNC_WIDTH_H,
> > > > + ctx->dt.hsync_len.min, true);
> > > >       /* HBP */
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > -                     HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min,
> false);
> > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > +                     HORIZONTAL_BACK_PORCH_H,
> > > > + ctx->dt.hback_porch.min, true);
> > > >       /* Vactive */
> > > >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
> > > >                       ctx->dt.vactive.min); @@ -663,9 +795,15 @@
> > > > static int anx7625_dsi_config(struct anx7625_data *ctx)
> > > >
> > > >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> > > >
> > > > -     /* DSC disable */
> > > > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > -                             R_DSC_CTRL_0, ~DSC_EN);
> > > > +     ret = anx7625_set_dsc_params(ctx);
> > > > +     if (ctx->dsc_en)
> > > > +             /* DSC enable */
> > > > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > > > +                                     R_DSC_CTRL_0, DSC_EN);
> > > > +     else
> > > > +             /* DSC disable */
> > > > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > +                                      R_DSC_CTRL_0, ~DSC_EN);
> > > >
> > > >       ret |= anx7625_api_dsi_config(ctx);
> > > >
> > > > @@ -2083,6 +2221,7 @@ static int anx7625_setup_dsi_device(struct
> > > anx7625_data *ctx)
> > > >               MIPI_DSI_MODE_VIDEO_HSE |
> > > >               MIPI_DSI_HS_PKT_END_ALIGNED;
> > > >
> > > > +     dsi->dsc = &ctx->dsc;
> > > >       ctx->dsi = dsi;
> > > >
> > > >       return 0;
> > > > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct
> > > > drm_bridge
> > > *bridge,
> > > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > > >       struct device *dev = ctx->dev;
> > > >
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > > > +     dev_dbg(dev, "drm mode checking\n");
> > > > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > > > +             return MODE_CLOCK_HIGH;
> > > > +
> > > > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > > > +             return MODE_CLOCK_LOW;
> > > >
> > > > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > > > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > > > -             DRM_DEV_DEBUG_DRIVER(dev,
> > > > -                                  "drm mode invalid, pixelclock too high.\n");
> > > > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3 !=
> > > > + 0))
> > >
> > > Magic number 3. Also is it actually required? I think DSC standard
> > > has no such requirement.
> > This is anx7625 limitation, if mode->hdisplay cannot be divided by 3,
> > then display will have overlap/shift issue.
> 
> Ack, add a comment or extend a commit message please.
OK, I'll add a comment
> 
> > >
> > > >               return MODE_CLOCK_HIGH;
> > > > -     }
> > > >
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > > > +     dev_dbg(dev, "drm mode valid.\n");
> > > >
> > > >       return MODE_OK;
> > > >  }
> > > >
> > > > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > > > +     int ret;
> > > > +     struct device *dev = ctx->dev;
> > > > +
> > > > +     ctx->dsc_en = en;
> > > > +
> > > > +     if (en) {
> > > > +             ctx->dsc.dsc_version_major = 1;
> > > > +             ctx->dsc.dsc_version_minor = 1;
> > > > +             ctx->dsc.slice_height = 8;
> > > > +             ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > > > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > > > +             ctx->dsc.bits_per_component = 8;
> > > > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > > > +             ctx->dsc.block_pred_enable = true;
> > > > +             ctx->dsc.native_420 = false;
> > > > +             ctx->dsc.native_422 = false;
> > > > +             ctx->dsc.simple_422 = false;
> > > > +             ctx->dsc.vbr_enable = false;
> > > > +             ctx->dsc.rc_model_size = DSC_RC_MODEL_SIZE_CONST;
> 
> This one is default, please drop.
OK
> 
> > > > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > > > +             ctx->dsc.pic_height = ctx->dt.vactive.min;
> 
> These two are set on the DSC encoder side.
OK, I'll remove it
> 
> > > > +             ctx->dsc.convert_rgb = 1;
> > > > +             ctx->dsc.vbr_enable = 0;
> > >
> > > A lot of this params should be coming from the sink device. You have
> > > to get them from the DPCD.
> > These parameter is just MIPI source and anx7625 and used only for DSC
> > feature,
> > Anx7625 is bridge IC, sink monitor only receive normal DP signal from
> > anx7625, sink device didn't know DSC information, no need read DPCD.
> 
> Thanks. From you commit message it is impossible to understand whether DSC
> happens between the host and your bridge or between the bridge and the
> monitor.
I'll add more detail in commit message
> 
> > >
> > > > +
> > > > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > > > +             drm_dsc_set_const_params(&ctx->dsc);
> > > > +
> > > > +             ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx-
> >dsc);
> > > > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > > > +             ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
> > > > +             if (ret < 0)
> > > > +                     dev_warn(dev, "drm_dsc_setup_rc_params ret
> > > > + %d\n", ret);
> > > > +
> > > > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> > >
> > > You have ignored return value. Please handle the function returning an error.
> > OK
> 
> All these functions are to be called on the DSC encoder side as it has to be able
> to infer DSC params.

I don't know, we co-work with MTK encoder, they need us to initial dsc data structure

> 
> > >
> > > > +
> > > > +             drm_dsc_pps_payload_pack((struct
> > > > + drm_dsc_picture_parameter_set
> > > *)&ctx->pps_table,
> > > > +                                      &ctx->dsc);
> > > > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > > > +     } else {
> > > > +             ctx->dsc.dsc_version_major = 0;
> > > > +             ctx->dsc.dsc_version_minor = 0;
> > > > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > > > +     }
> > > > +}
> > > > +
> > > >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > > >                                   const struct drm_display_mode *old_mode,
> > > >                                   const struct drm_display_mode
> > > > *mode) @@ -2244,6 +2431,11 @@ static void
> > > > anx7625_bridge_mode_set(struct
> > > drm_bridge *bridge,
> > > >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > > >                            mode->vsync_end,
> > > >                            mode->vtotal);
> > > > +
> > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > >
> > > What if the sink doesn't support DSC? The decision whether to enable
> > > DSC or not should be happening in the atomic_check(). Likewise
> > > mode_valid should be able to check if your bridge and the sink can
> > > agree on DSC params and reject modes if they can not.
> > Anx7625 is bridge IC, it receive MIPI data and DP output, DSC only
> > exist between SOC and Anx7625, sink monitor only receive normal DP
> > signal from anx7625, there is no compression at DP output, so no need to
> check sink device.
> 
> Well. Then the same question applies in the other direction: what if the host
> doesnt' support DSC?
If SOC host doesn't support DSC, then cannot display 4K30, currently, only debug with
MTK DSI encoder.
> 
> > >
> > > > +             anx7625_dsc_enable(ctx, true);
> > > > +     else
> > > > +             anx7625_dsc_enable(ctx, false);
> > > >  }
> > > >
> > > >  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> > > > @@
> > > > -2258,26 +2450,33 @@ static bool anx7625_bridge_mode_fixup(struct
> > > > drm_bridge *bridge,
> > > >
> > > >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> > > >
> > > > -     /* No need fixup for external monitor */
> > > > -     if (!ctx->pdata.panel_bridge)
> > > > -             return true;
> > > > -
> > > >       hsync = mode->hsync_end - mode->hsync_start;
> > > >       hfp = mode->hsync_start - mode->hdisplay;
> > > >       hbp = mode->htotal - mode->hsync_end;
> > > >       hblanking = mode->htotal - mode->hdisplay;
> > > >
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > clock(%d)\n",
> > > > -                          hsync, hfp, hbp, adj->clock);
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > htot(%d)\n",
> > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > -
> > > > +     dev_dbg(dev, "before mode fixup\n");
> > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > +             hsync, hfp, hbp, adj->clock);
> > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > > > +             adj->hsync_start, adj->hsync_end, adj->htotal);
> > >
> > > No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway, this
> > > should go to a separate commit.
> > OK, I'll not change it in this patch.
> > >
> > > >       adj_hfp = hfp;
> > > >       adj_hsync = hsync;
> > > >       adj_hbp = hbp;
> > > >       adj_hblanking = hblanking;
> > > >
> > > > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > > > +             adj_hsync = DSC_HSYNC_LEN;
> > > > +             adj_hfp = DSC_HFP_LEN;
> > > > +             adj_hbp = DSC_HBP_LEN;
> > > > +             vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
> > > > +             goto calculate_timing;
> > > > +     }
> > > > +
> > > > +     /* No need fixup for external monitor */
> > > > +     if (!ctx->pdata.panel_bridge)
> > > > +             return true;
> > > > +
> > > >       /* HFP needs to be even */
> > > >       if (hfp & 0x1) {
> > > >               adj_hfp += 1;
> > > > @@ -2349,16 +2548,21 @@ static bool
> > > > anx7625_bridge_mode_fixup(struct
> > > drm_bridge *bridge,
> > > >                       adj_hfp -= delta_adj;
> > > >       }
> > > >
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > clock(%d)\n",
> > > > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > +calculate_timing:
> > > > +
> > > > +     dev_dbg(dev, "after mode fixup\n");
> > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > >
> > > >       /* Reconstruct timing */
> > > >       adj->hsync_start = adj->hdisplay + adj_hfp;
> > > >       adj->hsync_end = adj->hsync_start + adj_hsync;
> > > >       adj->htotal = adj->hsync_end + adj_hbp;
> > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > htot(%d)\n",
> > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > +             adj->clock = (u64)vref * adj->htotal * adj->vtotal /
> > > > + 1000 / 1000;
> > > > +
> > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
> > > > +             adj->hsync_start, adj->hsync_end, adj->htotal,
> > > > + adj->clock);
> > > >
> > > >       return true;
> > > >  }
> > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > index eb5580f1ab2f..db931f5800b1 100644
> > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > @@ -149,6 +149,8 @@
> > > >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
> > > >  #define VIDEO_CONTROL_0      0x08
> > > >
> > > > +#define  TOTAL_LINES_L          0x12
> > > > +#define  TOTAL_LINES_H          0x13
> > > >  #define  ACTIVE_LINES_L         0x14
> > > >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> > > >  #define  VERTICAL_FRONT_PORCH   0x16
> > > > @@ -166,6 +168,32 @@
> > > >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> > > >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are reserved
> */
> > > >
> > > > +#define  H_BLANK_L                    0x3E
> > > > +#define  H_BLANK_H                    0x3F
> > > > +#define  DSC_COMPRESS_RATIO           3
> > > > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> > >
> > > This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode?
> > > Or does
> > > 1:3 come from some other ratio?
> > We only tested 1:3 compression ratio, 24bpp compress to 8bpp.
> 
> What are hardware limitations?
Anx7625 MIPI only support RGB888 24bpp. With DSC 3:1 compression,
MIPI TX output 8bpp.
> 
> > >
> > > > +#define  DSC_SLICE_NUM                2
> > > > +#define  DSC_PIXEL_CLOCK              250000
> > > > +#define  DSC_HSYNC_LEN                90
> > > > +#define  DSC_HFP_LEN                  177
> > > > +#define  DSC_HBP_LEN                  297
> > > > +
> > > > +#define  TOTAL_PIXEL_L_7E             0x50
> > > > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> > > > +#define  ACTIVE_PIXEL_L_7E            0x52
> > > > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> > > > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > > > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > > > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > > > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > > > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > > > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > > > +
> > > > +#define  PPS_SIZE                     128
> > > > +#define  PPS_BLOCK_SIZE               32
> > > > +#define  R_PPS_REG_0                  0x80
> > > > +#define  R_I2C_1                      0x81
> > > > +
> > > >  /******** END of I2C Address 0x72 *********/
> > > >
> > > >
> > >
> /***************************************************************/
> > > > @@ -415,6 +443,7 @@ enum audio_wd_len {
> > > >  #define MAX_EDID_BLOCK       3
> > > >  #define EDID_TRY_CNT 3
> > > >  #define SUPPORT_PIXEL_CLOCK  300000
> > > > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> > > >
> > > >  /***************** Display End *****************/
> > > >
> > > > @@ -454,6 +483,7 @@ struct anx7625_data {
> > > >       int hpd_high_cnt;
> > > >       int dp_en;
> > > >       int hdcp_cp;
> > > > +     bool dsc_en;
> > > >       /* Lock for work queue */
> > > >       struct mutex lock;
> > > >       struct device *dev;
> > > > @@ -479,6 +509,8 @@ struct anx7625_data {
> > > >       struct drm_connector *connector;
> > > >       struct mipi_dsi_device *dsi;
> > > >       struct drm_dp_aux aux;
> > > > +     struct drm_dsc_config dsc;
> > > > +     char pps_table[PPS_SIZE];
> > >
> > > pps_table and drm_dsc_config can vary depending on the mode and
> > > connected sink. THey should be a part of the atomic state rather
> > > than a long-living anx7625_data. So does dsc_en.
> > No need to check sink monitor, because DSC only exist between SOC and
> > Anx7625, sink monitor only receive normal DP signal from anx7625.
> > Anx7625 is responsible for decompression.
> 
> The same way, they depend on the selected video mode, don't they?
Actually it depends on pixel clock, if it is more than 250M, then need to do DSC.
> 
> > >
> > > >  };
> > > >
> > > >  #endif  /* __ANX7625_H__ */
> > > > --
> > > > 2.25.1
> > > >
> > >
> > > --
> > > With best wishes
> > > Dmitry
> 
> --
> With best wishes
> Dmitry
Dmitry Baryshkov Feb. 14, 2025, 1:43 p.m. UTC | #5
On Fri, Feb 14, 2025 at 01:05:04PM +0000, Xin Ji wrote:
> > -----Original Message-----
> > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > Sent: Friday, February 14, 2025 7:47 PM
> > To: Xin Ji <xji@analogixsemi.com>
> > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent Pinchart
> > <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>;
> > Jernej Skrabec <jernej.skrabec@gmail.com>; Maarten Lankhorst
> > <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>;
> > Thomas Zimmermann <tzimmermann@suse.de>; David Airlie
> > <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Bernie Liang
> > <bliang@analogixsemi.com>; Qilin Wen <qwen@analogixsemi.com>;
> > treapking@google.com; dri-devel@lists.freedesktop.org; linux-
> > kernel@vger.kernel.org
> > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> > 
> > 
> > On Fri, Feb 14, 2025 at 11:20:01AM +0000, Xin Ji wrote:
> > > > -----Original Message-----
> > > > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > > Sent: Thursday, February 13, 2025 9:04 PM
> > > > To: Xin Ji <xji@analogixsemi.com>
> > > > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > > > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent
> > > > Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas Karlman
> > > > <jonas@kwiboo.se>; Jernej Skrabec <jernej.skrabec@gmail.com>;
> > > > Maarten Lankhorst <maarten.lankhorst@linux.intel.com>; Maxime Ripard
> > > > <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>;
> > David
> > > > Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; Bernie
> > > > Liang <bliang@analogixsemi.com>; Qilin Wen <qwen@analogixsemi.com>;
> > > > treapking@google.com; dri-devel@lists.freedesktop.org; linux-
> > > > kernel@vger.kernel.org
> > > > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> > 
> > PLease remove such splats, use something more sensible.
> OK, I'll change the subject

It's not about the subject. Compare just "ABC DEF wrote:" and your
quatation header.

> > 
> > > >
> > > >
> > > > On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > > > > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and
> > > > > internal pixel clock(maximum 300M) limitation. Anx7625 must enable
> > > > > DSC feature while MIPI source want to output 4K30 resolution.
> > > >
> > > > This commit message is pretty hard to read and understand for a
> > > > non-native speaker. Please consider rewriting it so that it is easier to
> > understand it.
> > > >
> > > Thanks for the review, sorry about that, I'll rewriting the commit
> > > message
> > > > >
> > > > > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > > > > ---
> > > > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > > > > ++++++++++++++++++----  drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > ++++++++++++++++++|
> > > > > 32 +++
> > > > >  2 files changed, 284 insertions(+), 48 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > index 4be34d5c7a3b..7d86ab02f71c 100644
> > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > @@ -22,6 +22,7 @@
> > > > >
> > > > >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > > > > <drm/display/drm_dp_helper.h>
> > > > > +#include <drm/display/drm_dsc_helper.h>
> > > > >  #include <drm/display/drm_hdcp_helper.h>  #include
> > > > > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@ -476,6
> > > > > +477,138 @@ static int anx7625_set_k_value(struct anx7625_data
> > > > > +*ctx)
> > > > >                                MIPI_DIGITAL_ADJ_1, 0x3D);  }
> > > > >
> > > > > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > > > > +     int ret, i;
> > > > > +     u16 htotal, vtotal;
> > > > > +
> > > > > +     if (!ctx->dsc_en)
> > > > > +             return 0;
> > > > > +
> > > > > +     /* Htotal */
> > > > > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > +     /* Hactive */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > > > > +                              ctx->dt.hactive.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > +                              ctx->dt.hactive.min >> 8);
> > > > > +     /* HFP */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_FRONT_PORCH_L,
> > > > > +                              ctx->dt.hfront_porch.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_FRONT_PORCH_H,
> > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > +     /* HWS */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_SYNC_WIDTH_L,
> > > > > +                              ctx->dt.hsync_len.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_SYNC_WIDTH_H,
> > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > +     /* HBP */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_BACK_PORCH_L,
> > > > > +                              ctx->dt.hback_porch.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              HORIZONTAL_BACK_PORCH_H,
> > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > +     /* Vtotal */
> > > > > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > > > > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
> > > > > +                              vtotal);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
> > > > > +                              vtotal >> 8);
> > > > > +     /* Vactive */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_L,
> > > > > +                              ctx->dt.vactive.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_H,
> > > > > +                              ctx->dt.vactive.min >> 8);
> > > > > +     /* VFP */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > > > > +     /* VWS */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > > > > +     /* VBP */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > +                              VERTICAL_BACK_PORCH,
> > > > > + ctx->dt.vback_porch.min);
> > > >
> > > > This code mostly duplicates anx7625_dsi_video_timing_config() with
> > > > the I2C client being the only difference. Please consider extracting
> > > > a common helper to write the timings.
> > > It is hard to extracting a common helper, they are used different I2C
> > > slave address and timing register need divided by 3 if DSC enabled.
> > 
> > I2C client can be a parameter. Also please comment whether /3 is because of
> > bpp/bpc ratio or due to some other reason?
> > 
> > Does anx7625 support any mode other than 8bpp / 8bpc?
> I'll try to make a common function, anx7625 mipi only support RGB888. DSC 8bpp.
> /3 is because of DSC ration 1:3.

Please add this to the commit message, add a comment next to the
corresponding #define and use it instead of /3 all over the place.

> > 
> > > >
> > > > > +
> > > > > +     /* Htotal */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > TOTAL_PIXEL_L_7E,
> > > > > +                              htotal);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > TOTAL_PIXEL_H_7E,
> > > > > +                              htotal >> 8);
> > > > > +     /* Hactive */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > > > > +     /* HFP */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              HORIZON_FRONT_PORCH_L_7E,
> > > > > +                              ctx->dt.hfront_porch.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              HORIZON_FRONT_PORCH_H_7E,
> > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > +     /* HWS */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              HORIZON_SYNC_WIDTH_L_7E,
> > > > > +                              ctx->dt.hsync_len.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              HORIZON_SYNC_WIDTH_H_7E,
> > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > +     /* HBP */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              HORIZON_BACK_PORCH_L_7E,
> > > > > +                              ctx->dt.hback_porch.min);
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > +                              HORIZON_BACK_PORCH_H_7E,
> > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > +
> > > > > +     /* Config DSC decoder internal blank timing for decoder to start */
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > +                              H_BLANK_L,
> > > > > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > +                              H_BLANK_H,
> > > > > +                              dsc_div(htotal -
> > > > > + ctx->dt.hactive.min)
> > > > > + >> 8);
> > > > > +
> > > > > +     /* Compress ratio  RATIO bit[7:6] */
> > > > > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
> > > > > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > > > > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > > > > +     /*PPS table*/
> > > > > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > > > > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                                            R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > > > > +                                            &ctx->pps_table[i]);
> > > > > +
> > > > > +     return ret;
> > > > > +}
> > > > > +
> > > > > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > > > > +                             struct i2c_client *client,
> > > > > +                             u8 reg_addr, u16 reg_val, bool
> > > > > +high_byte) {
> > > > > +     u8 reg_data;
> > > > > +
> > > > > +     if (ctx->dsc_en)
> > > > > +             reg_val = dsc_div(reg_val);
> > > > > +
> > > > > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) & 0xFF;
> > > > > +
> > > > > +     return anx7625_reg_write(ctx, client, reg_addr, reg_data); }
> > > >
> > > > Ugh, no. Calculate htotal in the calling function and call
> > > > anx7625_reg_write() as you were doing that before.
> > > >
> > > anx7625_timing_write() is a common function, it was called many times,
> > > so we cannot calculate htotal in it.
> > 
> > On the caller side. I'd suggest to inline anx7625_timing_write() to make the code
> > more explicit.
> OK.
> > 
> > >
> > > > > +
> > > > >  static int anx7625_dsi_video_timing_config(struct anx7625_data
> > > > > *ctx) {
> > > > >       struct device *dev = ctx->dev; @@ -506,34 +639,33 @@ static
> > > > > int anx7625_dsi_video_timing_config(struct
> > > > anx7625_data *ctx)
> > > > >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > > > >                               MIPI_LANE_CTRL_0,
> > > > > ctx->pdata.mipi_lanes
> > > > > - 1);
> > > > >
> > > > > -     /* Htotal */
> > > > >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > +     /* Htotal */
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal, true);
> > > > >       /* Hactive */
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min, false);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > + ctx->dt.hactive.min, true);
> > > > >       /* HFP */
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_FRONT_PORCH_H,
> > > > > -                     ctx->dt.hfront_porch.min >> 8);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min,
> > false);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_FRONT_PORCH_H,
> > > > > + ctx->dt.hfront_porch.min, true);
> > > >
> > > > Are porches also compressed? I think blanking signal timings are
> > > > transferred as is, without compression.
> > > Porches not be compressed, anx7625 internal digital block will
> > > multiply by 3 while enable DSC feature, so the register must divided by 3.
> > 
> > Ack
> > 
> > > >
> > > > >       /* HWS */
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min, false);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_SYNC_WIDTH_H,
> > > > > + ctx->dt.hsync_len.min, true);
> > > > >       /* HBP */
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > -                     HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min,
> > false);
> > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > +                     HORIZONTAL_BACK_PORCH_H,
> > > > > + ctx->dt.hback_porch.min, true);
> > > > >       /* Vactive */
> > > > >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
> > > > >                       ctx->dt.vactive.min); @@ -663,9 +795,15 @@
> > > > > static int anx7625_dsi_config(struct anx7625_data *ctx)
> > > > >
> > > > >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> > > > >
> > > > > -     /* DSC disable */
> > > > > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > -                             R_DSC_CTRL_0, ~DSC_EN);
> > > > > +     ret = anx7625_set_dsc_params(ctx);
> > > > > +     if (ctx->dsc_en)
> > > > > +             /* DSC enable */
> > > > > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > > > > +                                     R_DSC_CTRL_0, DSC_EN);
> > > > > +     else
> > > > > +             /* DSC disable */
> > > > > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > +                                      R_DSC_CTRL_0, ~DSC_EN);
> > > > >
> > > > >       ret |= anx7625_api_dsi_config(ctx);
> > > > >
> > > > > @@ -2083,6 +2221,7 @@ static int anx7625_setup_dsi_device(struct
> > > > anx7625_data *ctx)
> > > > >               MIPI_DSI_MODE_VIDEO_HSE |
> > > > >               MIPI_DSI_HS_PKT_END_ALIGNED;
> > > > >
> > > > > +     dsi->dsc = &ctx->dsc;
> > > > >       ctx->dsi = dsi;
> > > > >
> > > > >       return 0;
> > > > > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct
> > > > > drm_bridge
> > > > *bridge,
> > > > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > > > >       struct device *dev = ctx->dev;
> > > > >
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > > > > +     dev_dbg(dev, "drm mode checking\n");
> > > > > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > > > > +             return MODE_CLOCK_HIGH;
> > > > > +
> > > > > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > > > > +             return MODE_CLOCK_LOW;
> > > > >
> > > > > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > > > > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > > > > -             DRM_DEV_DEBUG_DRIVER(dev,
> > > > > -                                  "drm mode invalid, pixelclock too high.\n");
> > > > > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3 !=
> > > > > + 0))
> > > >
> > > > Magic number 3. Also is it actually required? I think DSC standard
> > > > has no such requirement.
> > > This is anx7625 limitation, if mode->hdisplay cannot be divided by 3,
> > > then display will have overlap/shift issue.
> > 
> > Ack, add a comment or extend a commit message please.
> OK, I'll add a comment
> > 
> > > >
> > > > >               return MODE_CLOCK_HIGH;
> > > > > -     }
> > > > >
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > > > > +     dev_dbg(dev, "drm mode valid.\n");
> > > > >
> > > > >       return MODE_OK;
> > > > >  }
> > > > >
> > > > > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > > > > +     int ret;
> > > > > +     struct device *dev = ctx->dev;
> > > > > +
> > > > > +     ctx->dsc_en = en;
> > > > > +
> > > > > +     if (en) {
> > > > > +             ctx->dsc.dsc_version_major = 1;
> > > > > +             ctx->dsc.dsc_version_minor = 1;
> > > > > +             ctx->dsc.slice_height = 8;
> > > > > +             ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > > > > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > > > > +             ctx->dsc.bits_per_component = 8;
> > > > > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > > > > +             ctx->dsc.block_pred_enable = true;
> > > > > +             ctx->dsc.native_420 = false;
> > > > > +             ctx->dsc.native_422 = false;
> > > > > +             ctx->dsc.simple_422 = false;
> > > > > +             ctx->dsc.vbr_enable = false;
> > > > > +             ctx->dsc.rc_model_size = DSC_RC_MODEL_SIZE_CONST;
> > 
> > This one is default, please drop.
> OK
> > 
> > > > > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > > > > +             ctx->dsc.pic_height = ctx->dt.vactive.min;
> > 
> > These two are set on the DSC encoder side.
> OK, I'll remove it
> > 
> > > > > +             ctx->dsc.convert_rgb = 1;
> > > > > +             ctx->dsc.vbr_enable = 0;
> > > >
> > > > A lot of this params should be coming from the sink device. You have
> > > > to get them from the DPCD.
> > > These parameter is just MIPI source and anx7625 and used only for DSC
> > > feature,
> > > Anx7625 is bridge IC, sink monitor only receive normal DP signal from
> > > anx7625, sink device didn't know DSC information, no need read DPCD.
> > 
> > Thanks. From you commit message it is impossible to understand whether DSC
> > happens between the host and your bridge or between the bridge and the
> > monitor.
> I'll add more detail in commit message
> > 
> > > >
> > > > > +
> > > > > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > > > > +             drm_dsc_set_const_params(&ctx->dsc);
> > > > > +
> > > > > +             ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx-
> > >dsc);
> > > > > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > > > > +             ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
> > > > > +             if (ret < 0)
> > > > > +                     dev_warn(dev, "drm_dsc_setup_rc_params ret
> > > > > + %d\n", ret);
> > > > > +
> > > > > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> > > >
> > > > You have ignored return value. Please handle the function returning an error.
> > > OK
> > 
> > All these functions are to be called on the DSC encoder side as it has to be able
> > to infer DSC params.
> 
> I don't know, we co-work with MTK encoder, they need us to initial dsc data structure

As I wrote, encoder should be able to influence some of those params. As
such, DSC decoder should provide some values, then DSC encoder's
.pre_enable should be able to update those values (e.g. by setting
.pic_width and .pic_height and/or disabling some of flags). Then the DSC
encoder should fill the rest of the params by calling all these
functions. Consider how drm/msm/dsi handles it.

> 
> > 
> > > >
> > > > > +
> > > > > +             drm_dsc_pps_payload_pack((struct
> > > > > + drm_dsc_picture_parameter_set
> > > > *)&ctx->pps_table,
> > > > > +                                      &ctx->dsc);
> > > > > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > > > > +     } else {
> > > > > +             ctx->dsc.dsc_version_major = 0;
> > > > > +             ctx->dsc.dsc_version_minor = 0;
> > > > > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > > > > +     }
> > > > > +}
> > > > > +
> > > > >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > > > >                                   const struct drm_display_mode *old_mode,
> > > > >                                   const struct drm_display_mode
> > > > > *mode) @@ -2244,6 +2431,11 @@ static void
> > > > > anx7625_bridge_mode_set(struct
> > > > drm_bridge *bridge,
> > > > >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > > > >                            mode->vsync_end,
> > > > >                            mode->vtotal);
> > > > > +
> > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > >
> > > > What if the sink doesn't support DSC? The decision whether to enable
> > > > DSC or not should be happening in the atomic_check(). Likewise
> > > > mode_valid should be able to check if your bridge and the sink can
> > > > agree on DSC params and reject modes if they can not.
> > > Anx7625 is bridge IC, it receive MIPI data and DP output, DSC only
> > > exist between SOC and Anx7625, sink monitor only receive normal DP
> > > signal from anx7625, there is no compression at DP output, so no need to
> > check sink device.
> > 
> > Well. Then the same question applies in the other direction: what if the host
> > doesnt' support DSC?
> If SOC host doesn't support DSC, then cannot display 4K30, currently, only debug with
> MTK DSI encoder.

The bridge is a generic driver. So while you test with Mediatek
platforms, you still have to think about a generic case and add
necessary checks.

> > 
> > > >
> > > > > +             anx7625_dsc_enable(ctx, true);
> > > > > +     else
> > > > > +             anx7625_dsc_enable(ctx, false);
> > > > >  }
> > > > >
> > > > >  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> > > > > @@
> > > > > -2258,26 +2450,33 @@ static bool anx7625_bridge_mode_fixup(struct
> > > > > drm_bridge *bridge,
> > > > >
> > > > >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> > > > >
> > > > > -     /* No need fixup for external monitor */
> > > > > -     if (!ctx->pdata.panel_bridge)
> > > > > -             return true;
> > > > > -
> > > > >       hsync = mode->hsync_end - mode->hsync_start;
> > > > >       hfp = mode->hsync_start - mode->hdisplay;
> > > > >       hbp = mode->htotal - mode->hsync_end;
> > > > >       hblanking = mode->htotal - mode->hdisplay;
> > > > >
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > clock(%d)\n",
> > > > > -                          hsync, hfp, hbp, adj->clock);
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > > htot(%d)\n",
> > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > -
> > > > > +     dev_dbg(dev, "before mode fixup\n");
> > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > +             hsync, hfp, hbp, adj->clock);
> > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > > > > +             adj->hsync_start, adj->hsync_end, adj->htotal);
> > > >
> > > > No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway, this
> > > > should go to a separate commit.
> > > OK, I'll not change it in this patch.
> > > >
> > > > >       adj_hfp = hfp;
> > > > >       adj_hsync = hsync;
> > > > >       adj_hbp = hbp;
> > > > >       adj_hblanking = hblanking;
> > > > >
> > > > > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > > > > +             adj_hsync = DSC_HSYNC_LEN;
> > > > > +             adj_hfp = DSC_HFP_LEN;
> > > > > +             adj_hbp = DSC_HBP_LEN;
> > > > > +             vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
> > > > > +             goto calculate_timing;
> > > > > +     }
> > > > > +
> > > > > +     /* No need fixup for external monitor */
> > > > > +     if (!ctx->pdata.panel_bridge)
> > > > > +             return true;
> > > > > +
> > > > >       /* HFP needs to be even */
> > > > >       if (hfp & 0x1) {
> > > > >               adj_hfp += 1;
> > > > > @@ -2349,16 +2548,21 @@ static bool
> > > > > anx7625_bridge_mode_fixup(struct
> > > > drm_bridge *bridge,
> > > > >                       adj_hfp -= delta_adj;
> > > > >       }
> > > > >
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > clock(%d)\n",
> > > > > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > +calculate_timing:
> > > > > +
> > > > > +     dev_dbg(dev, "after mode fixup\n");
> > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > >
> > > > >       /* Reconstruct timing */
> > > > >       adj->hsync_start = adj->hdisplay + adj_hfp;
> > > > >       adj->hsync_end = adj->hsync_start + adj_hsync;
> > > > >       adj->htotal = adj->hsync_end + adj_hbp;
> > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > > htot(%d)\n",
> > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > > +             adj->clock = (u64)vref * adj->htotal * adj->vtotal /
> > > > > + 1000 / 1000;
> > > > > +
> > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
> > > > > +             adj->hsync_start, adj->hsync_end, adj->htotal,
> > > > > + adj->clock);
> > > > >
> > > > >       return true;
> > > > >  }
> > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > index eb5580f1ab2f..db931f5800b1 100644
> > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > @@ -149,6 +149,8 @@
> > > > >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
> > > > >  #define VIDEO_CONTROL_0      0x08
> > > > >
> > > > > +#define  TOTAL_LINES_L          0x12
> > > > > +#define  TOTAL_LINES_H          0x13
> > > > >  #define  ACTIVE_LINES_L         0x14
> > > > >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> > > > >  #define  VERTICAL_FRONT_PORCH   0x16
> > > > > @@ -166,6 +168,32 @@
> > > > >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> > > > >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are reserved
> > */
> > > > >
> > > > > +#define  H_BLANK_L                    0x3E
> > > > > +#define  H_BLANK_H                    0x3F
> > > > > +#define  DSC_COMPRESS_RATIO           3
> > > > > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> > > >
> > > > This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode?
> > > > Or does
> > > > 1:3 come from some other ratio?
> > > We only tested 1:3 compression ratio, 24bpp compress to 8bpp.
> > 
> > What are hardware limitations?
> Anx7625 MIPI only support RGB888 24bpp. With DSC 3:1 compression,
> MIPI TX output 8bpp.

As I wrote, a comment please.

> > 
> > > >
> > > > > +#define  DSC_SLICE_NUM                2
> > > > > +#define  DSC_PIXEL_CLOCK              250000
> > > > > +#define  DSC_HSYNC_LEN                90
> > > > > +#define  DSC_HFP_LEN                  177
> > > > > +#define  DSC_HBP_LEN                  297
> > > > > +
> > > > > +#define  TOTAL_PIXEL_L_7E             0x50
> > > > > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> > > > > +#define  ACTIVE_PIXEL_L_7E            0x52
> > > > > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> > > > > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > > > > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > > > > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > > > > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > > > > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > > > > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > > > > +
> > > > > +#define  PPS_SIZE                     128
> > > > > +#define  PPS_BLOCK_SIZE               32
> > > > > +#define  R_PPS_REG_0                  0x80
> > > > > +#define  R_I2C_1                      0x81
> > > > > +
> > > > >  /******** END of I2C Address 0x72 *********/
> > > > >
> > > > >
> > > >
> > /***************************************************************/
> > > > > @@ -415,6 +443,7 @@ enum audio_wd_len {
> > > > >  #define MAX_EDID_BLOCK       3
> > > > >  #define EDID_TRY_CNT 3
> > > > >  #define SUPPORT_PIXEL_CLOCK  300000
> > > > > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> > > > >
> > > > >  /***************** Display End *****************/
> > > > >
> > > > > @@ -454,6 +483,7 @@ struct anx7625_data {
> > > > >       int hpd_high_cnt;
> > > > >       int dp_en;
> > > > >       int hdcp_cp;
> > > > > +     bool dsc_en;
> > > > >       /* Lock for work queue */
> > > > >       struct mutex lock;
> > > > >       struct device *dev;
> > > > > @@ -479,6 +509,8 @@ struct anx7625_data {
> > > > >       struct drm_connector *connector;
> > > > >       struct mipi_dsi_device *dsi;
> > > > >       struct drm_dp_aux aux;
> > > > > +     struct drm_dsc_config dsc;
> > > > > +     char pps_table[PPS_SIZE];
> > > >
> > > > pps_table and drm_dsc_config can vary depending on the mode and
> > > > connected sink. THey should be a part of the atomic state rather
> > > > than a long-living anx7625_data. So does dsc_en.
> > > No need to check sink monitor, because DSC only exist between SOC and
> > > Anx7625, sink monitor only receive normal DP signal from anx7625.
> > > Anx7625 is responsible for decompression.
> > 
> > The same way, they depend on the selected video mode, don't they?
> Actually it depends on pixel clock, if it is more than 250M, then need to do DSC.

Yes. So you should check if you can enable DSC in .atomic_check() and
set dsc_en correspondingly. At the same time in .atomic_check() you can
not modify anx7625_data as it is a check time, commit can be rejected or
it can be a test-only check. So dsc_en should go to
drm_bridge_state-wrapping structure.

At the same time I don't see a value in storing the packed PPS table, it is a
short-lived data.

> > 
> > > >
> > > > >  };
> > > > >
> > > > >  #endif  /* __ANX7625_H__ */
> > > > > --
> > > > > 2.25.1
> > > > >
> > > >
> > > > --
> > > > With best wishes
> > > > Dmitry
> > 
> > --
> > With best wishes
> > Dmitry
Xin Ji Feb. 14, 2025, 3:30 p.m. UTC | #6
> > > > > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > > > Sent: Thursday, February 13, 2025 9:04 PM
> > > > > To: Xin Ji <xji@analogixsemi.com>
> > > > > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > > > > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>;
> > > > > Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas
> > > > > Karlman <jonas@kwiboo.se>; Jernej Skrabec
> > > > > <jernej.skrabec@gmail.com>; Maarten Lankhorst
> > > > > <maarten.lankhorst@linux.intel.com>; Maxime Ripard
> > > > > <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>;
> > > David
> > > > > Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>;
> > > > > Bernie Liang <bliang@analogixsemi.com>; Qilin Wen
> > > > > <qwen@analogixsemi.com>; treapking@google.com;
> > > > > dri-devel@lists.freedesktop.org; linux- kernel@vger.kernel.org
> > > > > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> > >
> > > PLease remove such splats, use something more sensible.
> > OK, I'll change the subject
> 
> It's not about the subject. Compare just "ABC DEF wrote:" and your quatation
> header.
Sorry, these message is automatically added by Outlook, I'll remove it.
> 
> > >
> > > > >
> > > > >
> > > > > On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > > > > > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and
> > > > > > internal pixel clock(maximum 300M) limitation. Anx7625 must
> > > > > > enable DSC feature while MIPI source want to output 4K30 resolution.
> > > > >
> > > > > This commit message is pretty hard to read and understand for a
> > > > > non-native speaker. Please consider rewriting it so that it is
> > > > > easier to
> > > understand it.
> > > > >
> > > > Thanks for the review, sorry about that, I'll rewriting the commit
> > > > message
> > > > > >
> > > > > > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > > > > > ---
> > > > > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > > > > > ++++++++++++++++++----
> > > > > > ++++++++++++++++++drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > ++++++++++++++++++|
> > > > > > 32 +++
> > > > > >  2 files changed, 284 insertions(+), 48 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > index 4be34d5c7a3b..7d86ab02f71c 100644
> > > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > @@ -22,6 +22,7 @@
> > > > > >
> > > > > >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > > > > > <drm/display/drm_dp_helper.h>
> > > > > > +#include <drm/display/drm_dsc_helper.h>
> > > > > >  #include <drm/display/drm_hdcp_helper.h>  #include
> > > > > > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@
> > > > > > -476,6
> > > > > > +477,138 @@ static int anx7625_set_k_value(struct anx7625_data
> > > > > > +*ctx)
> > > > > >                                MIPI_DIGITAL_ADJ_1, 0x3D);  }
> > > > > >
> > > > > > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > > > > > +     int ret, i;
> > > > > > +     u16 htotal, vtotal;
> > > > > > +
> > > > > > +     if (!ctx->dsc_en)
> > > > > > +             return 0;
> > > > > > +
> > > > > > +     /* Htotal */
> > > > > > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > > +     /* Hactive */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > > > > > +                              ctx->dt.hactive.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > > +                              ctx->dt.hactive.min >> 8);
> > > > > > +     /* HFP */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_FRONT_PORCH_L,
> > > > > > +                              ctx->dt.hfront_porch.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_FRONT_PORCH_H,
> > > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > > +     /* HWS */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_SYNC_WIDTH_L,
> > > > > > +                              ctx->dt.hsync_len.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_SYNC_WIDTH_H,
> > > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > > +     /* HBP */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_BACK_PORCH_L,
> > > > > > +                              ctx->dt.hback_porch.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              HORIZONTAL_BACK_PORCH_H,
> > > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > > +     /* Vtotal */
> > > > > > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > > > > > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> TOTAL_LINES_L,
> > > > > > +                              vtotal);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> TOTAL_LINES_H,
> > > > > > +                              vtotal >> 8);
> > > > > > +     /* Vactive */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> ACTIVE_LINES_L,
> > > > > > +                              ctx->dt.vactive.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> ACTIVE_LINES_H,
> > > > > > +                              ctx->dt.vactive.min >> 8);
> > > > > > +     /* VFP */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > > > > > +     /* VWS */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > > > > > +     /* VBP */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > +                              VERTICAL_BACK_PORCH,
> > > > > > + ctx->dt.vback_porch.min);
> > > > >
> > > > > This code mostly duplicates anx7625_dsi_video_timing_config()
> > > > > with the I2C client being the only difference. Please consider
> > > > > extracting a common helper to write the timings.
> > > > It is hard to extracting a common helper, they are used different
> > > > I2C slave address and timing register need divided by 3 if DSC enabled.
> > >
> > > I2C client can be a parameter. Also please comment whether /3 is
> > > because of bpp/bpc ratio or due to some other reason?
> > >
> > > Does anx7625 support any mode other than 8bpp / 8bpc?
> > I'll try to make a common function, anx7625 mipi only support RGB888. DSC
> 8bpp.
> > /3 is because of DSC ration 1:3.
> 
> Please add this to the commit message, add a comment next to the
> corresponding #define and use it instead of /3 all over the place.
OK
> 
> > >
> > > > >
> > > > > > +
> > > > > > +     /* Htotal */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > TOTAL_PIXEL_L_7E,
> > > > > > +                              htotal);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > TOTAL_PIXEL_H_7E,
> > > > > > +                              htotal >> 8);
> > > > > > +     /* Hactive */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > > > > > +     /* HFP */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              HORIZON_FRONT_PORCH_L_7E,
> > > > > > +                              ctx->dt.hfront_porch.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              HORIZON_FRONT_PORCH_H_7E,
> > > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > > +     /* HWS */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              HORIZON_SYNC_WIDTH_L_7E,
> > > > > > +                              ctx->dt.hsync_len.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              HORIZON_SYNC_WIDTH_H_7E,
> > > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > > +     /* HBP */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              HORIZON_BACK_PORCH_L_7E,
> > > > > > +                              ctx->dt.hback_porch.min);
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                              HORIZON_BACK_PORCH_H_7E,
> > > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > > +
> > > > > > +     /* Config DSC decoder internal blank timing for decoder to start */
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > > +                              H_BLANK_L,
> > > > > > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > > +                              H_BLANK_H,
> > > > > > +                              dsc_div(htotal -
> > > > > > + ctx->dt.hactive.min)
> > > > > > + >> 8);
> > > > > > +
> > > > > > +     /* Compress ratio  RATIO bit[7:6] */
> > > > > > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> 0x3F);
> > > > > > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > > > > > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > > > > > +     /*PPS table*/
> > > > > > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > > > > > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                                            R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > > > > > +
> > > > > > + &ctx->pps_table[i]);
> > > > > > +
> > > > > > +     return ret;
> > > > > > +}
> > > > > > +
> > > > > > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > > > > > +                             struct i2c_client *client,
> > > > > > +                             u8 reg_addr, u16 reg_val, bool
> > > > > > +high_byte) {
> > > > > > +     u8 reg_data;
> > > > > > +
> > > > > > +     if (ctx->dsc_en)
> > > > > > +             reg_val = dsc_div(reg_val);
> > > > > > +
> > > > > > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) &
> > > > > > + 0xFF;
> > > > > > +
> > > > > > +     return anx7625_reg_write(ctx, client, reg_addr,
> > > > > > + reg_data); }
> > > > >
> > > > > Ugh, no. Calculate htotal in the calling function and call
> > > > > anx7625_reg_write() as you were doing that before.
> > > > >
> > > > anx7625_timing_write() is a common function, it was called many
> > > > times, so we cannot calculate htotal in it.
> > >
> > > On the caller side. I'd suggest to inline anx7625_timing_write() to
> > > make the code more explicit.
> > OK.
> > >
> > > >
> > > > > > +
> > > > > >  static int anx7625_dsi_video_timing_config(struct
> > > > > > anx7625_data
> > > > > > *ctx) {
> > > > > >       struct device *dev = ctx->dev; @@ -506,34 +639,33 @@
> > > > > > static int anx7625_dsi_video_timing_config(struct
> > > > > anx7625_data *ctx)
> > > > > >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > > > > >                               MIPI_LANE_CTRL_0,
> > > > > > ctx->pdata.mipi_lanes
> > > > > > - 1);
> > > > > >
> > > > > > -     /* Htotal */
> > > > > >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > +     /* Htotal */
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal,
> > > > > > + true);
> > > > > >       /* Hactive */
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min &
> 0xFF);
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min,
> false);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > > + ctx->dt.hactive.min, true);
> > > > > >       /* HFP */
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_FRONT_PORCH_L, ctx-
> >dt.hfront_porch.min);
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_FRONT_PORCH_H,
> > > > > > -                     ctx->dt.hfront_porch.min >> 8);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_FRONT_PORCH_L,
> > > > > > + ctx->dt.hfront_porch.min,
> > > false);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_FRONT_PORCH_H,
> > > > > > + ctx->dt.hfront_porch.min, true);
> > > > >
> > > > > Are porches also compressed? I think blanking signal timings are
> > > > > transferred as is, without compression.
> > > > Porches not be compressed, anx7625 internal digital block will
> > > > multiply by 3 while enable DSC feature, so the register must divided by 3.
> > >
> > > Ack
> > >
> > > > >
> > > > > >       /* HWS */
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >>
> 8);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min,
> false);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_SYNC_WIDTH_H,
> > > > > > + ctx->dt.hsync_len.min, true);
> > > > > >       /* HBP */
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > -                     HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >>
> 8);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_BACK_PORCH_L,
> > > > > > + ctx->dt.hback_porch.min,
> > > false);
> > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > +                     HORIZONTAL_BACK_PORCH_H,
> > > > > > + ctx->dt.hback_porch.min, true);
> > > > > >       /* Vactive */
> > > > > >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> ACTIVE_LINES_L,
> > > > > >                       ctx->dt.vactive.min); @@ -663,9 +795,15
> > > > > > @@ static int anx7625_dsi_config(struct anx7625_data *ctx)
> > > > > >
> > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> > > > > >
> > > > > > -     /* DSC disable */
> > > > > > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > -                             R_DSC_CTRL_0, ~DSC_EN);
> > > > > > +     ret = anx7625_set_dsc_params(ctx);
> > > > > > +     if (ctx->dsc_en)
> > > > > > +             /* DSC enable */
> > > > > > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                                     R_DSC_CTRL_0, DSC_EN);
> > > > > > +     else
> > > > > > +             /* DSC disable */
> > > > > > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > +                                      R_DSC_CTRL_0, ~DSC_EN);
> > > > > >
> > > > > >       ret |= anx7625_api_dsi_config(ctx);
> > > > > >
> > > > > > @@ -2083,6 +2221,7 @@ static int
> > > > > > anx7625_setup_dsi_device(struct
> > > > > anx7625_data *ctx)
> > > > > >               MIPI_DSI_MODE_VIDEO_HSE |
> > > > > >               MIPI_DSI_HS_PKT_END_ALIGNED;
> > > > > >
> > > > > > +     dsi->dsc = &ctx->dsc;
> > > > > >       ctx->dsi = dsi;
> > > > > >
> > > > > >       return 0;
> > > > > > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct
> > > > > > drm_bridge
> > > > > *bridge,
> > > > > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > > > > >       struct device *dev = ctx->dev;
> > > > > >
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > > > > > +     dev_dbg(dev, "drm mode checking\n");
> > > > > > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > > > > > +             return MODE_CLOCK_HIGH;
> > > > > > +
> > > > > > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > > > > > +             return MODE_CLOCK_LOW;
> > > > > >
> > > > > > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > > > > > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > > > > > -             DRM_DEV_DEBUG_DRIVER(dev,
> > > > > > -                                  "drm mode invalid, pixelclock too high.\n");
> > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3
> > > > > > + !=
> > > > > > + 0))
> > > > >
> > > > > Magic number 3. Also is it actually required? I think DSC
> > > > > standard has no such requirement.
> > > > This is anx7625 limitation, if mode->hdisplay cannot be divided by
> > > > 3, then display will have overlap/shift issue.
> > >
> > > Ack, add a comment or extend a commit message please.
> > OK, I'll add a comment
> > >
> > > > >
> > > > > >               return MODE_CLOCK_HIGH;
> > > > > > -     }
> > > > > >
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > > > > > +     dev_dbg(dev, "drm mode valid.\n");
> > > > > >
> > > > > >       return MODE_OK;
> > > > > >  }
> > > > > >
> > > > > > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > > > > > +     int ret;
> > > > > > +     struct device *dev = ctx->dev;
> > > > > > +
> > > > > > +     ctx->dsc_en = en;
> > > > > > +
> > > > > > +     if (en) {
> > > > > > +             ctx->dsc.dsc_version_major = 1;
> > > > > > +             ctx->dsc.dsc_version_minor = 1;
> > > > > > +             ctx->dsc.slice_height = 8;
> > > > > > +             ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > > > > > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > > > > > +             ctx->dsc.bits_per_component = 8;
> > > > > > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > > > > > +             ctx->dsc.block_pred_enable = true;
> > > > > > +             ctx->dsc.native_420 = false;
> > > > > > +             ctx->dsc.native_422 = false;
> > > > > > +             ctx->dsc.simple_422 = false;
> > > > > > +             ctx->dsc.vbr_enable = false;
> > > > > > +             ctx->dsc.rc_model_size =
> > > > > > + DSC_RC_MODEL_SIZE_CONST;
> > >
> > > This one is default, please drop.
> > OK
> > >
> > > > > > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > > > > > +             ctx->dsc.pic_height = ctx->dt.vactive.min;
> > >
> > > These two are set on the DSC encoder side.
> > OK, I'll remove it
> > >
> > > > > > +             ctx->dsc.convert_rgb = 1;
> > > > > > +             ctx->dsc.vbr_enable = 0;
> > > > >
> > > > > A lot of this params should be coming from the sink device. You
> > > > > have to get them from the DPCD.
> > > > These parameter is just MIPI source and anx7625 and used only for
> > > > DSC feature,
> > > > Anx7625 is bridge IC, sink monitor only receive normal DP signal
> > > > from anx7625, sink device didn't know DSC information, no need read
> DPCD.
> > >
> > > Thanks. From you commit message it is impossible to understand
> > > whether DSC happens between the host and your bridge or between the
> > > bridge and the monitor.
> > I'll add more detail in commit message
> > >
> > > > >
> > > > > > +
> > > > > > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > > > > > +             drm_dsc_set_const_params(&ctx->dsc);
> > > > > > +
> > > > > > +             ctx->dsc.initial_scale_value =
> > > > > > + drm_dsc_initial_scale_value(&ctx-
> > > >dsc);
> > > > > > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > > > > > +             ret = drm_dsc_setup_rc_params(&ctx->dsc,
> DRM_DSC_1_2_444);
> > > > > > +             if (ret < 0)
> > > > > > +                     dev_warn(dev, "drm_dsc_setup_rc_params
> > > > > > + ret %d\n", ret);
> > > > > > +
> > > > > > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> > > > >
> > > > > You have ignored return value. Please handle the function returning an
> error.
> > > > OK
> > >
> > > All these functions are to be called on the DSC encoder side as it
> > > has to be able to infer DSC params.
> >
> > I don't know, we co-work with MTK encoder, they need us to initial dsc
> > data structure
> 
> As I wrote, encoder should be able to influence some of those params. As such,
> DSC decoder should provide some values, then DSC encoder's .pre_enable
> should be able to update those values (e.g. by setting .pic_width and .pic_height
> and/or disabling some of flags). Then the DSC encoder should fill the rest of the
> params by calling all these functions. Consider how drm/msm/dsi handles it.
OK, I'll check it.
> 
> >
> > >
> > > > >
> > > > > > +
> > > > > > +             drm_dsc_pps_payload_pack((struct
> > > > > > + drm_dsc_picture_parameter_set
> > > > > *)&ctx->pps_table,
> > > > > > +                                      &ctx->dsc);
> > > > > > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > > > > > +     } else {
> > > > > > +             ctx->dsc.dsc_version_major = 0;
> > > > > > +             ctx->dsc.dsc_version_minor = 0;
> > > > > > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > > > > > +     }
> > > > > > +}
> > > > > > +
> > > > > >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > > > > >                                   const struct drm_display_mode *old_mode,
> > > > > >                                   const struct
> > > > > > drm_display_mode
> > > > > > *mode) @@ -2244,6 +2431,11 @@ static void
> > > > > > anx7625_bridge_mode_set(struct
> > > > > drm_bridge *bridge,
> > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > > > > >                            mode->vsync_end,
> > > > > >                            mode->vtotal);
> > > > > > +
> > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > >
> > > > > What if the sink doesn't support DSC? The decision whether to
> > > > > enable DSC or not should be happening in the atomic_check().
> > > > > Likewise mode_valid should be able to check if your bridge and
> > > > > the sink can agree on DSC params and reject modes if they can not.
> > > > Anx7625 is bridge IC, it receive MIPI data and DP output, DSC only
> > > > exist between SOC and Anx7625, sink monitor only receive normal DP
> > > > signal from anx7625, there is no compression at DP output, so no
> > > > need to
> > > check sink device.
> > >
> > > Well. Then the same question applies in the other direction: what if
> > > the host doesnt' support DSC?
> > If SOC host doesn't support DSC, then cannot display 4K30, currently,
> > only debug with MTK DSI encoder.
> 
> The bridge is a generic driver. So while you test with Mediatek platforms, you
> still have to think about a generic case and add necessary checks.
OK, I'll check it.
> 
> > >
> > > > >
> > > > > > +             anx7625_dsc_enable(ctx, true);
> > > > > > +     else
> > > > > > +             anx7625_dsc_enable(ctx, false);
> > > > > >  }
> > > > > >
> > > > > >  static bool anx7625_bridge_mode_fixup(struct drm_bridge
> > > > > > *bridge, @@
> > > > > > -2258,26 +2450,33 @@ static bool
> > > > > > anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> > > > > >
> > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> > > > > >
> > > > > > -     /* No need fixup for external monitor */
> > > > > > -     if (!ctx->pdata.panel_bridge)
> > > > > > -             return true;
> > > > > > -
> > > > > >       hsync = mode->hsync_end - mode->hsync_start;
> > > > > >       hfp = mode->hsync_start - mode->hdisplay;
> > > > > >       hbp = mode->htotal - mode->hsync_end;
> > > > > >       hblanking = mode->htotal - mode->hdisplay;
> > > > > >
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > > clock(%d)\n",
> > > > > > -                          hsync, hfp, hbp, adj->clock);
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > > > htot(%d)\n",
> > > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > > -
> > > > > > +     dev_dbg(dev, "before mode fixup\n");
> > > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > > +             hsync, hfp, hbp, adj->clock);
> > > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > > > > > +             adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > >
> > > > > No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway,
> > > > > this should go to a separate commit.
> > > > OK, I'll not change it in this patch.
> > > > >
> > > > > >       adj_hfp = hfp;
> > > > > >       adj_hsync = hsync;
> > > > > >       adj_hbp = hbp;
> > > > > >       adj_hblanking = hblanking;
> > > > > >
> > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > > > > > +             adj_hsync = DSC_HSYNC_LEN;
> > > > > > +             adj_hfp = DSC_HFP_LEN;
> > > > > > +             adj_hbp = DSC_HBP_LEN;
> > > > > > +             vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj-
> >vtotal);
> > > > > > +             goto calculate_timing;
> > > > > > +     }
> > > > > > +
> > > > > > +     /* No need fixup for external monitor */
> > > > > > +     if (!ctx->pdata.panel_bridge)
> > > > > > +             return true;
> > > > > > +
> > > > > >       /* HFP needs to be even */
> > > > > >       if (hfp & 0x1) {
> > > > > >               adj_hfp += 1;
> > > > > > @@ -2349,16 +2548,21 @@ static bool
> > > > > > anx7625_bridge_mode_fixup(struct
> > > > > drm_bridge *bridge,
> > > > > >                       adj_hfp -= delta_adj;
> > > > > >       }
> > > > > >
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > > clock(%d)\n",
> > > > > > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > > +calculate_timing:
> > > > > > +
> > > > > > +     dev_dbg(dev, "after mode fixup\n");
> > > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > >
> > > > > >       /* Reconstruct timing */
> > > > > >       adj->hsync_start = adj->hdisplay + adj_hfp;
> > > > > >       adj->hsync_end = adj->hsync_start + adj_hsync;
> > > > > >       adj->htotal = adj->hsync_end + adj_hbp;
> > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > > > htot(%d)\n",
> > > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > > > +             adj->clock = (u64)vref * adj->htotal *
> > > > > > + adj->vtotal /
> > > > > > + 1000 / 1000;
> > > > > > +
> > > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d),
> clock(%d)\n",
> > > > > > +             adj->hsync_start, adj->hsync_end, adj->htotal,
> > > > > > + adj->clock);
> > > > > >
> > > > > >       return true;
> > > > > >  }
> > > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > index eb5580f1ab2f..db931f5800b1 100644
> > > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > @@ -149,6 +149,8 @@
> > > > > >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
> > > > > >  #define VIDEO_CONTROL_0      0x08
> > > > > >
> > > > > > +#define  TOTAL_LINES_L          0x12
> > > > > > +#define  TOTAL_LINES_H          0x13
> > > > > >  #define  ACTIVE_LINES_L         0x14
> > > > > >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> > > > > >  #define  VERTICAL_FRONT_PORCH   0x16
> > > > > > @@ -166,6 +168,32 @@
> > > > > >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> > > > > >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are
> reserved
> > > */
> > > > > >
> > > > > > +#define  H_BLANK_L                    0x3E
> > > > > > +#define  H_BLANK_H                    0x3F
> > > > > > +#define  DSC_COMPRESS_RATIO           3
> > > > > > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> > > > >
> > > > > This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode?
> > > > > Or does
> > > > > 1:3 come from some other ratio?
> > > > We only tested 1:3 compression ratio, 24bpp compress to 8bpp.
> > >
> > > What are hardware limitations?
> > Anx7625 MIPI only support RGB888 24bpp. With DSC 3:1 compression, MIPI
> > TX output 8bpp.
> 
> As I wrote, a comment please.
OK
> 
> > >
> > > > >
> > > > > > +#define  DSC_SLICE_NUM                2
> > > > > > +#define  DSC_PIXEL_CLOCK              250000
> > > > > > +#define  DSC_HSYNC_LEN                90
> > > > > > +#define  DSC_HFP_LEN                  177
> > > > > > +#define  DSC_HBP_LEN                  297
> > > > > > +
> > > > > > +#define  TOTAL_PIXEL_L_7E             0x50
> > > > > > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> > > > > > +#define  ACTIVE_PIXEL_L_7E            0x52
> > > > > > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> > > > > > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > > > > > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > > > > > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > > > > > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > > > > > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > > > > > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > > > > > +
> > > > > > +#define  PPS_SIZE                     128
> > > > > > +#define  PPS_BLOCK_SIZE               32
> > > > > > +#define  R_PPS_REG_0                  0x80
> > > > > > +#define  R_I2C_1                      0x81
> > > > > > +
> > > > > >  /******** END of I2C Address 0x72 *********/
> > > > > >
> > > > > >
> > > > >
> > >
> /***************************************************************/
> > > > > > @@ -415,6 +443,7 @@ enum audio_wd_len {
> > > > > >  #define MAX_EDID_BLOCK       3
> > > > > >  #define EDID_TRY_CNT 3
> > > > > >  #define SUPPORT_PIXEL_CLOCK  300000
> > > > > > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> > > > > >
> > > > > >  /***************** Display End *****************/
> > > > > >
> > > > > > @@ -454,6 +483,7 @@ struct anx7625_data {
> > > > > >       int hpd_high_cnt;
> > > > > >       int dp_en;
> > > > > >       int hdcp_cp;
> > > > > > +     bool dsc_en;
> > > > > >       /* Lock for work queue */
> > > > > >       struct mutex lock;
> > > > > >       struct device *dev;
> > > > > > @@ -479,6 +509,8 @@ struct anx7625_data {
> > > > > >       struct drm_connector *connector;
> > > > > >       struct mipi_dsi_device *dsi;
> > > > > >       struct drm_dp_aux aux;
> > > > > > +     struct drm_dsc_config dsc;
> > > > > > +     char pps_table[PPS_SIZE];
> > > > >
> > > > > pps_table and drm_dsc_config can vary depending on the mode and
> > > > > connected sink. THey should be a part of the atomic state rather
> > > > > than a long-living anx7625_data. So does dsc_en.
> > > > No need to check sink monitor, because DSC only exist between SOC
> > > > and Anx7625, sink monitor only receive normal DP signal from anx7625.
> > > > Anx7625 is responsible for decompression.
> > >
> > > The same way, they depend on the selected video mode, don't they?
> > Actually it depends on pixel clock, if it is more than 250M, then need to do DSC.
> 
> Yes. So you should check if you can enable DSC in .atomic_check() and set
> dsc_en correspondingly. At the same time in .atomic_check() you can not modify
> anx7625_data as it is a check time, commit can be rejected or it can be a test-
> only check. So dsc_en should go to drm_bridge_state-wrapping structure.
> 
> At the same time I don't see a value in storing the packed PPS table, it is a short-
> lived data.
Do you mean we can maintain dsc_en flag for each timing/resolution in drm_bridge_state
structure, and set it in .atomic_check(), and check the drm_bridge_state's  dsc_en  in
.atomic_enable()? I don't know how to make a drm_bridge_state-wrapping structure.

Based on the design, anx7625 chip needs 128 bytes pps table, without it,
chip cannot decompress DSC data.

> 
> > >
> > > > >
> > > > > >  };
> > > > > >
> > > > > >  #endif  /* __ANX7625_H__ */
> > > > > > --
> > > > > > 2.25.1
> > > > > >
> > > > >
> > > > > --
> > > > > With best wishes
> > > > > Dmitry
> > >
> > > --
> > > With best wishes
> > > Dmitry
> 
> --
> With best wishes
> Dmitry
Dmitry Baryshkov Feb. 14, 2025, 4:01 p.m. UTC | #7
On Fri, Feb 14, 2025 at 03:30:57PM +0000, Xin Ji wrote:
> > > > > > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > > > > Sent: Thursday, February 13, 2025 9:04 PM
> > > > > > To: Xin Ji <xji@analogixsemi.com>
> > > > > > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > > > > > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>;
> > > > > > Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas
> > > > > > Karlman <jonas@kwiboo.se>; Jernej Skrabec
> > > > > > <jernej.skrabec@gmail.com>; Maarten Lankhorst
> > > > > > <maarten.lankhorst@linux.intel.com>; Maxime Ripard
> > > > > > <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>;
> > > > David
> > > > > > Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>;
> > > > > > Bernie Liang <bliang@analogixsemi.com>; Qilin Wen
> > > > > > <qwen@analogixsemi.com>; treapking@google.com;
> > > > > > dri-devel@lists.freedesktop.org; linux- kernel@vger.kernel.org
> > > > > > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> > > >
> > > > PLease remove such splats, use something more sensible.
> > > OK, I'll change the subject
> > 
> > It's not about the subject. Compare just "ABC DEF wrote:" and your quatation
> > header.
> Sorry, these message is automatically added by Outlook, I'll remove it.
> > 
> > > >
> > > > > >
> > > > > >
> > > > > > On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > > > > > > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and
> > > > > > > internal pixel clock(maximum 300M) limitation. Anx7625 must
> > > > > > > enable DSC feature while MIPI source want to output 4K30 resolution.
> > > > > >
> > > > > > This commit message is pretty hard to read and understand for a
> > > > > > non-native speaker. Please consider rewriting it so that it is
> > > > > > easier to
> > > > understand it.
> > > > > >
> > > > > Thanks for the review, sorry about that, I'll rewriting the commit
> > > > > message
> > > > > > >
> > > > > > > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > > > > > > ---
> > > > > > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > > > > > > ++++++++++++++++++----
> > > > > > > ++++++++++++++++++drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > ++++++++++++++++++|
> > > > > > > 32 +++
> > > > > > >  2 files changed, 284 insertions(+), 48 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > index 4be34d5c7a3b..7d86ab02f71c 100644
> > > > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > @@ -22,6 +22,7 @@
> > > > > > >
> > > > > > >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > > > > > > <drm/display/drm_dp_helper.h>
> > > > > > > +#include <drm/display/drm_dsc_helper.h>
> > > > > > >  #include <drm/display/drm_hdcp_helper.h>  #include
> > > > > > > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@
> > > > > > > -476,6
> > > > > > > +477,138 @@ static int anx7625_set_k_value(struct anx7625_data
> > > > > > > +*ctx)
> > > > > > >                                MIPI_DIGITAL_ADJ_1, 0x3D);  }
> > > > > > >
> > > > > > > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > > > > > > +     int ret, i;
> > > > > > > +     u16 htotal, vtotal;
> > > > > > > +
> > > > > > > +     if (!ctx->dsc_en)
> > > > > > > +             return 0;
> > > > > > > +
> > > > > > > +     /* Htotal */
> > > > > > > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > > > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > > > +     /* Hactive */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > > > > > > +                              ctx->dt.hactive.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > > > +                              ctx->dt.hactive.min >> 8);
> > > > > > > +     /* HFP */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_FRONT_PORCH_L,
> > > > > > > +                              ctx->dt.hfront_porch.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_FRONT_PORCH_H,
> > > > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > > > +     /* HWS */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_SYNC_WIDTH_L,
> > > > > > > +                              ctx->dt.hsync_len.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_SYNC_WIDTH_H,
> > > > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > > > +     /* HBP */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_BACK_PORCH_L,
> > > > > > > +                              ctx->dt.hback_porch.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              HORIZONTAL_BACK_PORCH_H,
> > > > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > > > +     /* Vtotal */
> > > > > > > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > > > > > > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > TOTAL_LINES_L,
> > > > > > > +                              vtotal);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > TOTAL_LINES_H,
> > > > > > > +                              vtotal >> 8);
> > > > > > > +     /* Vactive */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > ACTIVE_LINES_L,
> > > > > > > +                              ctx->dt.vactive.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > ACTIVE_LINES_H,
> > > > > > > +                              ctx->dt.vactive.min >> 8);
> > > > > > > +     /* VFP */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> > > > > > > +     /* VWS */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > > > > > > +     /* VBP */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > +                              VERTICAL_BACK_PORCH,
> > > > > > > + ctx->dt.vback_porch.min);
> > > > > >
> > > > > > This code mostly duplicates anx7625_dsi_video_timing_config()
> > > > > > with the I2C client being the only difference. Please consider
> > > > > > extracting a common helper to write the timings.
> > > > > It is hard to extracting a common helper, they are used different
> > > > > I2C slave address and timing register need divided by 3 if DSC enabled.
> > > >
> > > > I2C client can be a parameter. Also please comment whether /3 is
> > > > because of bpp/bpc ratio or due to some other reason?
> > > >
> > > > Does anx7625 support any mode other than 8bpp / 8bpc?
> > > I'll try to make a common function, anx7625 mipi only support RGB888. DSC
> > 8bpp.
> > > /3 is because of DSC ration 1:3.
> > 
> > Please add this to the commit message, add a comment next to the
> > corresponding #define and use it instead of /3 all over the place.
> OK
> > 
> > > >
> > > > > >
> > > > > > > +
> > > > > > > +     /* Htotal */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > TOTAL_PIXEL_L_7E,
> > > > > > > +                              htotal);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > TOTAL_PIXEL_H_7E,
> > > > > > > +                              htotal >> 8);
> > > > > > > +     /* Hactive */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > > > > > > +     /* HFP */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              HORIZON_FRONT_PORCH_L_7E,
> > > > > > > +                              ctx->dt.hfront_porch.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              HORIZON_FRONT_PORCH_H_7E,
> > > > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > > > +     /* HWS */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              HORIZON_SYNC_WIDTH_L_7E,
> > > > > > > +                              ctx->dt.hsync_len.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              HORIZON_SYNC_WIDTH_H_7E,
> > > > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > > > +     /* HBP */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              HORIZON_BACK_PORCH_L_7E,
> > > > > > > +                              ctx->dt.hback_porch.min);
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                              HORIZON_BACK_PORCH_H_7E,
> > > > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > > > +
> > > > > > > +     /* Config DSC decoder internal blank timing for decoder to start */
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > > > +                              H_BLANK_L,
> > > > > > > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > > > +                              H_BLANK_H,
> > > > > > > +                              dsc_div(htotal -
> > > > > > > + ctx->dt.hactive.min)
> > > > > > > + >> 8);
> > > > > > > +
> > > > > > > +     /* Compress ratio  RATIO bit[7:6] */
> > > > > > > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > 0x3F);
> > > > > > > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > > > > > > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > > > > > > +     /*PPS table*/
> > > > > > > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > > > > > > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                                            R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
> > > > > > > +
> > > > > > > + &ctx->pps_table[i]);
> > > > > > > +
> > > > > > > +     return ret;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > > > > > > +                             struct i2c_client *client,
> > > > > > > +                             u8 reg_addr, u16 reg_val, bool
> > > > > > > +high_byte) {
> > > > > > > +     u8 reg_data;
> > > > > > > +
> > > > > > > +     if (ctx->dsc_en)
> > > > > > > +             reg_val = dsc_div(reg_val);
> > > > > > > +
> > > > > > > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) &
> > > > > > > + 0xFF;
> > > > > > > +
> > > > > > > +     return anx7625_reg_write(ctx, client, reg_addr,
> > > > > > > + reg_data); }
> > > > > >
> > > > > > Ugh, no. Calculate htotal in the calling function and call
> > > > > > anx7625_reg_write() as you were doing that before.
> > > > > >
> > > > > anx7625_timing_write() is a common function, it was called many
> > > > > times, so we cannot calculate htotal in it.
> > > >
> > > > On the caller side. I'd suggest to inline anx7625_timing_write() to
> > > > make the code more explicit.
> > > OK.
> > > >
> > > > >
> > > > > > > +
> > > > > > >  static int anx7625_dsi_video_timing_config(struct
> > > > > > > anx7625_data
> > > > > > > *ctx) {
> > > > > > >       struct device *dev = ctx->dev; @@ -506,34 +639,33 @@
> > > > > > > static int anx7625_dsi_video_timing_config(struct
> > > > > > anx7625_data *ctx)
> > > > > > >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > > > > > >                               MIPI_LANE_CTRL_0,
> > > > > > > ctx->pdata.mipi_lanes
> > > > > > > - 1);
> > > > > > >
> > > > > > > -     /* Htotal */
> > > > > > >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > > > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > > > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > > +     /* Htotal */
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal,
> > > > > > > + true);
> > > > > > >       /* Hactive */
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min &
> > 0xFF);
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min,
> > false);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > > > + ctx->dt.hactive.min, true);
> > > > > > >       /* HFP */
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_FRONT_PORCH_L, ctx-
> > >dt.hfront_porch.min);
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_FRONT_PORCH_H,
> > > > > > > -                     ctx->dt.hfront_porch.min >> 8);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_FRONT_PORCH_L,
> > > > > > > + ctx->dt.hfront_porch.min,
> > > > false);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_FRONT_PORCH_H,
> > > > > > > + ctx->dt.hfront_porch.min, true);
> > > > > >
> > > > > > Are porches also compressed? I think blanking signal timings are
> > > > > > transferred as is, without compression.
> > > > > Porches not be compressed, anx7625 internal digital block will
> > > > > multiply by 3 while enable DSC feature, so the register must divided by 3.
> > > >
> > > > Ack
> > > >
> > > > > >
> > > > > > >       /* HWS */
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >>
> > 8);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min,
> > false);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_SYNC_WIDTH_H,
> > > > > > > + ctx->dt.hsync_len.min, true);
> > > > > > >       /* HBP */
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > -                     HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >>
> > 8);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_BACK_PORCH_L,
> > > > > > > + ctx->dt.hback_porch.min,
> > > > false);
> > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > +                     HORIZONTAL_BACK_PORCH_H,
> > > > > > > + ctx->dt.hback_porch.min, true);
> > > > > > >       /* Vactive */
> > > > > > >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > ACTIVE_LINES_L,
> > > > > > >                       ctx->dt.vactive.min); @@ -663,9 +795,15
> > > > > > > @@ static int anx7625_dsi_config(struct anx7625_data *ctx)
> > > > > > >
> > > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> > > > > > >
> > > > > > > -     /* DSC disable */
> > > > > > > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > > -                             R_DSC_CTRL_0, ~DSC_EN);
> > > > > > > +     ret = anx7625_set_dsc_params(ctx);
> > > > > > > +     if (ctx->dsc_en)
> > > > > > > +             /* DSC enable */
> > > > > > > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                                     R_DSC_CTRL_0, DSC_EN);
> > > > > > > +     else
> > > > > > > +             /* DSC disable */
> > > > > > > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > > +                                      R_DSC_CTRL_0, ~DSC_EN);
> > > > > > >
> > > > > > >       ret |= anx7625_api_dsi_config(ctx);
> > > > > > >
> > > > > > > @@ -2083,6 +2221,7 @@ static int
> > > > > > > anx7625_setup_dsi_device(struct
> > > > > > anx7625_data *ctx)
> > > > > > >               MIPI_DSI_MODE_VIDEO_HSE |
> > > > > > >               MIPI_DSI_HS_PKT_END_ALIGNED;
> > > > > > >
> > > > > > > +     dsi->dsc = &ctx->dsc;
> > > > > > >       ctx->dsi = dsi;
> > > > > > >
> > > > > > >       return 0;
> > > > > > > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct
> > > > > > > drm_bridge
> > > > > > *bridge,
> > > > > > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > > > > > >       struct device *dev = ctx->dev;
> > > > > > >
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > > > > > > +     dev_dbg(dev, "drm mode checking\n");
> > > > > > > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > > > > > > +             return MODE_CLOCK_HIGH;
> > > > > > > +
> > > > > > > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > > > > > > +             return MODE_CLOCK_LOW;
> > > > > > >
> > > > > > > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > > > > > > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > > > > > > -             DRM_DEV_DEBUG_DRIVER(dev,
> > > > > > > -                                  "drm mode invalid, pixelclock too high.\n");
> > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3
> > > > > > > + !=
> > > > > > > + 0))
> > > > > >
> > > > > > Magic number 3. Also is it actually required? I think DSC
> > > > > > standard has no such requirement.
> > > > > This is anx7625 limitation, if mode->hdisplay cannot be divided by
> > > > > 3, then display will have overlap/shift issue.
> > > >
> > > > Ack, add a comment or extend a commit message please.
> > > OK, I'll add a comment
> > > >
> > > > > >
> > > > > > >               return MODE_CLOCK_HIGH;
> > > > > > > -     }
> > > > > > >
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > > > > > > +     dev_dbg(dev, "drm mode valid.\n");
> > > > > > >
> > > > > > >       return MODE_OK;
> > > > > > >  }
> > > > > > >
> > > > > > > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en) {
> > > > > > > +     int ret;
> > > > > > > +     struct device *dev = ctx->dev;
> > > > > > > +
> > > > > > > +     ctx->dsc_en = en;
> > > > > > > +
> > > > > > > +     if (en) {
> > > > > > > +             ctx->dsc.dsc_version_major = 1;
> > > > > > > +             ctx->dsc.dsc_version_minor = 1;
> > > > > > > +             ctx->dsc.slice_height = 8;
> > > > > > > +             ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
> > > > > > > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > > > > > > +             ctx->dsc.bits_per_component = 8;
> > > > > > > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > > > > > > +             ctx->dsc.block_pred_enable = true;
> > > > > > > +             ctx->dsc.native_420 = false;
> > > > > > > +             ctx->dsc.native_422 = false;
> > > > > > > +             ctx->dsc.simple_422 = false;
> > > > > > > +             ctx->dsc.vbr_enable = false;
> > > > > > > +             ctx->dsc.rc_model_size =
> > > > > > > + DSC_RC_MODEL_SIZE_CONST;
> > > >
> > > > This one is default, please drop.
> > > OK
> > > >
> > > > > > > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > > > > > > +             ctx->dsc.pic_height = ctx->dt.vactive.min;
> > > >
> > > > These two are set on the DSC encoder side.
> > > OK, I'll remove it
> > > >
> > > > > > > +             ctx->dsc.convert_rgb = 1;
> > > > > > > +             ctx->dsc.vbr_enable = 0;
> > > > > >
> > > > > > A lot of this params should be coming from the sink device. You
> > > > > > have to get them from the DPCD.
> > > > > These parameter is just MIPI source and anx7625 and used only for
> > > > > DSC feature,
> > > > > Anx7625 is bridge IC, sink monitor only receive normal DP signal
> > > > > from anx7625, sink device didn't know DSC information, no need read
> > DPCD.
> > > >
> > > > Thanks. From you commit message it is impossible to understand
> > > > whether DSC happens between the host and your bridge or between the
> > > > bridge and the monitor.
> > > I'll add more detail in commit message
> > > >
> > > > > >
> > > > > > > +
> > > > > > > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > > > > > > +             drm_dsc_set_const_params(&ctx->dsc);
> > > > > > > +
> > > > > > > +             ctx->dsc.initial_scale_value =
> > > > > > > + drm_dsc_initial_scale_value(&ctx-
> > > > >dsc);
> > > > > > > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
> > > > > > > +             ret = drm_dsc_setup_rc_params(&ctx->dsc,
> > DRM_DSC_1_2_444);
> > > > > > > +             if (ret < 0)
> > > > > > > +                     dev_warn(dev, "drm_dsc_setup_rc_params
> > > > > > > + ret %d\n", ret);
> > > > > > > +
> > > > > > > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> > > > > >
> > > > > > You have ignored return value. Please handle the function returning an
> > error.
> > > > > OK
> > > >
> > > > All these functions are to be called on the DSC encoder side as it
> > > > has to be able to infer DSC params.
> > >
> > > I don't know, we co-work with MTK encoder, they need us to initial dsc
> > > data structure
> > 
> > As I wrote, encoder should be able to influence some of those params. As such,
> > DSC decoder should provide some values, then DSC encoder's .pre_enable
> > should be able to update those values (e.g. by setting .pic_width and .pic_height
> > and/or disabling some of flags). Then the DSC encoder should fill the rest of the
> > params by calling all these functions. Consider how drm/msm/dsi handles it.
> OK, I'll check it.
> > 
> > >
> > > >
> > > > > >
> > > > > > > +
> > > > > > > +             drm_dsc_pps_payload_pack((struct
> > > > > > > + drm_dsc_picture_parameter_set
> > > > > > *)&ctx->pps_table,
> > > > > > > +                                      &ctx->dsc);
> > > > > > > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > > > > > > +     } else {
> > > > > > > +             ctx->dsc.dsc_version_major = 0;
> > > > > > > +             ctx->dsc.dsc_version_minor = 0;
> > > > > > > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > > > > > > +     }
> > > > > > > +}
> > > > > > > +
> > > > > > >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > > > > > >                                   const struct drm_display_mode *old_mode,
> > > > > > >                                   const struct
> > > > > > > drm_display_mode
> > > > > > > *mode) @@ -2244,6 +2431,11 @@ static void
> > > > > > > anx7625_bridge_mode_set(struct
> > > > > > drm_bridge *bridge,
> > > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > > > > > >                            mode->vsync_end,
> > > > > > >                            mode->vtotal);
> > > > > > > +
> > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > > >
> > > > > > What if the sink doesn't support DSC? The decision whether to
> > > > > > enable DSC or not should be happening in the atomic_check().
> > > > > > Likewise mode_valid should be able to check if your bridge and
> > > > > > the sink can agree on DSC params and reject modes if they can not.
> > > > > Anx7625 is bridge IC, it receive MIPI data and DP output, DSC only
> > > > > exist between SOC and Anx7625, sink monitor only receive normal DP
> > > > > signal from anx7625, there is no compression at DP output, so no
> > > > > need to
> > > > check sink device.
> > > >
> > > > Well. Then the same question applies in the other direction: what if
> > > > the host doesnt' support DSC?
> > > If SOC host doesn't support DSC, then cannot display 4K30, currently,
> > > only debug with MTK DSI encoder.
> > 
> > The bridge is a generic driver. So while you test with Mediatek platforms, you
> > still have to think about a generic case and add necessary checks.
> OK, I'll check it.
> > 
> > > >
> > > > > >
> > > > > > > +             anx7625_dsc_enable(ctx, true);
> > > > > > > +     else
> > > > > > > +             anx7625_dsc_enable(ctx, false);
> > > > > > >  }
> > > > > > >
> > > > > > >  static bool anx7625_bridge_mode_fixup(struct drm_bridge
> > > > > > > *bridge, @@
> > > > > > > -2258,26 +2450,33 @@ static bool
> > > > > > > anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> > > > > > >
> > > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> > > > > > >
> > > > > > > -     /* No need fixup for external monitor */
> > > > > > > -     if (!ctx->pdata.panel_bridge)
> > > > > > > -             return true;
> > > > > > > -
> > > > > > >       hsync = mode->hsync_end - mode->hsync_start;
> > > > > > >       hfp = mode->hsync_start - mode->hdisplay;
> > > > > > >       hbp = mode->htotal - mode->hsync_end;
> > > > > > >       hblanking = mode->htotal - mode->hdisplay;
> > > > > > >
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > > > clock(%d)\n",
> > > > > > > -                          hsync, hfp, hbp, adj->clock);
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > > > > htot(%d)\n",
> > > > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > > > -
> > > > > > > +     dev_dbg(dev, "before mode fixup\n");
> > > > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > > > +             hsync, hfp, hbp, adj->clock);
> > > > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > > > > > > +             adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > >
> > > > > > No. Please use drm_dbg_driver(), but not dev_dbg(). And anyway,
> > > > > > this should go to a separate commit.
> > > > > OK, I'll not change it in this patch.
> > > > > >
> > > > > > >       adj_hfp = hfp;
> > > > > > >       adj_hsync = hsync;
> > > > > > >       adj_hbp = hbp;
> > > > > > >       adj_hblanking = hblanking;
> > > > > > >
> > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > > > > > > +             adj_hsync = DSC_HSYNC_LEN;
> > > > > > > +             adj_hfp = DSC_HFP_LEN;
> > > > > > > +             adj_hbp = DSC_HBP_LEN;
> > > > > > > +             vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj-
> > >vtotal);
> > > > > > > +             goto calculate_timing;
> > > > > > > +     }
> > > > > > > +
> > > > > > > +     /* No need fixup for external monitor */
> > > > > > > +     if (!ctx->pdata.panel_bridge)
> > > > > > > +             return true;
> > > > > > > +
> > > > > > >       /* HFP needs to be even */
> > > > > > >       if (hfp & 0x1) {
> > > > > > >               adj_hfp += 1;
> > > > > > > @@ -2349,16 +2548,21 @@ static bool
> > > > > > > anx7625_bridge_mode_fixup(struct
> > > > > > drm_bridge *bridge,
> > > > > > >                       adj_hfp -= delta_adj;
> > > > > > >       }
> > > > > > >
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > > > clock(%d)\n",
> > > > > > > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > > > +calculate_timing:
> > > > > > > +
> > > > > > > +     dev_dbg(dev, "after mode fixup\n");
> > > > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > > > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > > >
> > > > > > >       /* Reconstruct timing */
> > > > > > >       adj->hsync_start = adj->hdisplay + adj_hfp;
> > > > > > >       adj->hsync_end = adj->hsync_start + adj_hsync;
> > > > > > >       adj->htotal = adj->hsync_end + adj_hbp;
> > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d),
> > > > > > htot(%d)\n",
> > > > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > > > > +             adj->clock = (u64)vref * adj->htotal *
> > > > > > > + adj->vtotal /
> > > > > > > + 1000 / 1000;
> > > > > > > +
> > > > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d),
> > clock(%d)\n",
> > > > > > > +             adj->hsync_start, adj->hsync_end, adj->htotal,
> > > > > > > + adj->clock);
> > > > > > >
> > > > > > >       return true;
> > > > > > >  }
> > > > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > index eb5580f1ab2f..db931f5800b1 100644
> > > > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > @@ -149,6 +149,8 @@
> > > > > > >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
> > > > > > >  #define VIDEO_CONTROL_0      0x08
> > > > > > >
> > > > > > > +#define  TOTAL_LINES_L          0x12
> > > > > > > +#define  TOTAL_LINES_H          0x13
> > > > > > >  #define  ACTIVE_LINES_L         0x14
> > > > > > >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> > > > > > >  #define  VERTICAL_FRONT_PORCH   0x16
> > > > > > > @@ -166,6 +168,32 @@
> > > > > > >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> > > > > > >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are
> > reserved
> > > > */
> > > > > > >
> > > > > > > +#define  H_BLANK_L                    0x3E
> > > > > > > +#define  H_BLANK_H                    0x3F
> > > > > > > +#define  DSC_COMPRESS_RATIO           3
> > > > > > > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> > > > > >
> > > > > > This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode?
> > > > > > Or does
> > > > > > 1:3 come from some other ratio?
> > > > > We only tested 1:3 compression ratio, 24bpp compress to 8bpp.
> > > >
> > > > What are hardware limitations?
> > > Anx7625 MIPI only support RGB888 24bpp. With DSC 3:1 compression, MIPI
> > > TX output 8bpp.
> > 
> > As I wrote, a comment please.
> OK
> > 
> > > >
> > > > > >
> > > > > > > +#define  DSC_SLICE_NUM                2
> > > > > > > +#define  DSC_PIXEL_CLOCK              250000
> > > > > > > +#define  DSC_HSYNC_LEN                90
> > > > > > > +#define  DSC_HFP_LEN                  177
> > > > > > > +#define  DSC_HBP_LEN                  297
> > > > > > > +
> > > > > > > +#define  TOTAL_PIXEL_L_7E             0x50
> > > > > > > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
> > > > > > > +#define  ACTIVE_PIXEL_L_7E            0x52
> > > > > > > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
> > > > > > > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > > > > > > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > > > > > > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > > > > > > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > > > > > > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > > > > > > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > > > > > > +
> > > > > > > +#define  PPS_SIZE                     128
> > > > > > > +#define  PPS_BLOCK_SIZE               32
> > > > > > > +#define  R_PPS_REG_0                  0x80
> > > > > > > +#define  R_I2C_1                      0x81
> > > > > > > +
> > > > > > >  /******** END of I2C Address 0x72 *********/
> > > > > > >
> > > > > > >
> > > > > >
> > > >
> > /***************************************************************/
> > > > > > > @@ -415,6 +443,7 @@ enum audio_wd_len {
> > > > > > >  #define MAX_EDID_BLOCK       3
> > > > > > >  #define EDID_TRY_CNT 3
> > > > > > >  #define SUPPORT_PIXEL_CLOCK  300000
> > > > > > > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> > > > > > >
> > > > > > >  /***************** Display End *****************/
> > > > > > >
> > > > > > > @@ -454,6 +483,7 @@ struct anx7625_data {
> > > > > > >       int hpd_high_cnt;
> > > > > > >       int dp_en;
> > > > > > >       int hdcp_cp;
> > > > > > > +     bool dsc_en;
> > > > > > >       /* Lock for work queue */
> > > > > > >       struct mutex lock;
> > > > > > >       struct device *dev;
> > > > > > > @@ -479,6 +509,8 @@ struct anx7625_data {
> > > > > > >       struct drm_connector *connector;
> > > > > > >       struct mipi_dsi_device *dsi;
> > > > > > >       struct drm_dp_aux aux;
> > > > > > > +     struct drm_dsc_config dsc;
> > > > > > > +     char pps_table[PPS_SIZE];
> > > > > >
> > > > > > pps_table and drm_dsc_config can vary depending on the mode and
> > > > > > connected sink. THey should be a part of the atomic state rather
> > > > > > than a long-living anx7625_data. So does dsc_en.
> > > > > No need to check sink monitor, because DSC only exist between SOC
> > > > > and Anx7625, sink monitor only receive normal DP signal from anx7625.
> > > > > Anx7625 is responsible for decompression.
> > > >
> > > > The same way, they depend on the selected video mode, don't they?
> > > Actually it depends on pixel clock, if it is more than 250M, then need to do DSC.
> > 
> > Yes. So you should check if you can enable DSC in .atomic_check() and set
> > dsc_en correspondingly. At the same time in .atomic_check() you can not modify
> > anx7625_data as it is a check time, commit can be rejected or it can be a test-
> > only check. So dsc_en should go to drm_bridge_state-wrapping structure.
> > 
> > At the same time I don't see a value in storing the packed PPS table, it is a short-
> > lived data.
> Do you mean we can maintain dsc_en flag for each timing/resolution in drm_bridge_state
> structure, and set it in .atomic_check(), and check the drm_bridge_state's  dsc_en  in
> .atomic_enable()? I don't know how to make a drm_bridge_state-wrapping structure.

Ideally yes. You should define
  struct anx7625_bridge_state {
    struct drm_bridge_state base;
    bool dsc_en;
  };

Then define your own versions of atomic_reset and
.atomic_duplicate_state callbacks.

Note, we currently don't have a way to check that the DSI host actually
supports DSC, you have to invent it.

> 
> Based on the design, anx7625 chip needs 128 bytes pps table, without it,
> chip cannot decompress DSC data.

Yes, that's clear. But it doesn't have to be a part of the anx7625_data.
Allocate it on stack, fill it, program it, forget it.

> > 
> > > >
> > > > > >
> > > > > > >  };
> > > > > > >
> > > > > > >  #endif  /* __ANX7625_H__ */
> > > > > > > --
> > > > > > > 2.25.1
> > > > > > >
> > > > > >
> > > > > > --
> > > > > > With best wishes
> > > > > > Dmitry
> > > >
> > > > --
> > > > With best wishes
> > > > Dmitry
> > 
> > --
> > With best wishes
> > Dmitry
kernel test robot Feb. 14, 2025, 9:28 p.m. UTC | #8
Hi Xin,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on drm-misc/drm-misc-next v6.14-rc2 next-20250214]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Xin-Ji/drm-bridge-anx7625-Enable-DSC-feature/20250213-203558
base:   linus/master
patch link:    https://lore.kernel.org/r/20250213123331.3016824-1-xji%40analogixsemi.com
patch subject: [PATCH] drm/bridge:anx7625: Enable DSC feature
config: arm-randconfig-003-20250215 (https://download.01.org/0day-ci/archive/20250215/202502150516.xZBLDIlz-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250215/202502150516.xZBLDIlz-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502150516.xZBLDIlz-lkp@intel.com/

All errors (new ones prefixed by >>):

   arm-linux-gnueabi-ld: drivers/gpu/drm/bridge/analogix/anx7625.o: in function `anx7625_bridge_mode_fixup':
>> drivers/gpu/drm/bridge/analogix/anx7625.c:2472:(.text.anx7625_bridge_mode_fixup+0x9e): undefined reference to `__aeabi_uldivmod'
>> arm-linux-gnueabi-ld: drivers/gpu/drm/bridge/analogix/anx7625.c:2562:(.text.anx7625_bridge_mode_fixup+0x10e): undefined reference to `__aeabi_uldivmod'


vim +2472 drivers/gpu/drm/bridge/analogix/anx7625.c

  2440	
  2441	static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
  2442					      const struct drm_display_mode *mode,
  2443					      struct drm_display_mode *adj)
  2444	{
  2445		struct anx7625_data *ctx = bridge_to_anx7625(bridge);
  2446		struct device *dev = ctx->dev;
  2447		u32 hsync, hfp, hbp, hblanking;
  2448		u32 adj_hsync, adj_hfp, adj_hbp, adj_hblanking, delta_adj;
  2449		u32 vref, adj_clock;
  2450	
  2451		DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
  2452	
  2453		hsync = mode->hsync_end - mode->hsync_start;
  2454		hfp = mode->hsync_start - mode->hdisplay;
  2455		hbp = mode->htotal - mode->hsync_end;
  2456		hblanking = mode->htotal - mode->hdisplay;
  2457	
  2458		dev_dbg(dev, "before mode fixup\n");
  2459		dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
  2460			hsync, hfp, hbp, adj->clock);
  2461		dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
  2462			adj->hsync_start, adj->hsync_end, adj->htotal);
  2463		adj_hfp = hfp;
  2464		adj_hsync = hsync;
  2465		adj_hbp = hbp;
  2466		adj_hblanking = hblanking;
  2467	
  2468		if (mode->clock > DSC_PIXEL_CLOCK) {
  2469			adj_hsync = DSC_HSYNC_LEN;
  2470			adj_hfp = DSC_HFP_LEN;
  2471			adj_hbp = DSC_HBP_LEN;
> 2472			vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
  2473			goto calculate_timing;
  2474		}
  2475	
  2476		/* No need fixup for external monitor */
  2477		if (!ctx->pdata.panel_bridge)
  2478			return true;
  2479	
  2480		/* HFP needs to be even */
  2481		if (hfp & 0x1) {
  2482			adj_hfp += 1;
  2483			adj_hblanking += 1;
  2484		}
  2485	
  2486		/* HBP needs to be even */
  2487		if (hbp & 0x1) {
  2488			adj_hbp -= 1;
  2489			adj_hblanking -= 1;
  2490		}
  2491	
  2492		/* HSYNC needs to be even */
  2493		if (hsync & 0x1) {
  2494			if (adj_hblanking < hblanking)
  2495				adj_hsync += 1;
  2496			else
  2497				adj_hsync -= 1;
  2498		}
  2499	
  2500		/*
  2501		 * Once illegal timing detected, use default HFP, HSYNC, HBP
  2502		 * This adjusting made for built-in eDP panel, for the externel
  2503		 * DP monitor, may need return false.
  2504		 */
  2505		if (hblanking < HBLANKING_MIN || (hfp < HP_MIN && hbp < HP_MIN)) {
  2506			adj_hsync = SYNC_LEN_DEF;
  2507			adj_hfp = HFP_HBP_DEF;
  2508			adj_hbp = HFP_HBP_DEF;
  2509			vref = adj->clock * 1000 / (adj->htotal * adj->vtotal);
  2510			if (hblanking < HBLANKING_MIN) {
  2511				delta_adj = HBLANKING_MIN - hblanking;
  2512				adj_clock = vref * delta_adj * adj->vtotal;
  2513				adj->clock += DIV_ROUND_UP(adj_clock, 1000);
  2514			} else {
  2515				delta_adj = hblanking - HBLANKING_MIN;
  2516				adj_clock = vref * delta_adj * adj->vtotal;
  2517				adj->clock -= DIV_ROUND_UP(adj_clock, 1000);
  2518			}
  2519	
  2520			DRM_WARN("illegal hblanking timing, use default.\n");
  2521			DRM_WARN("hfp(%d), hbp(%d), hsync(%d).\n", hfp, hbp, hsync);
  2522		} else if (adj_hfp < HP_MIN) {
  2523			/* Adjust hfp if hfp less than HP_MIN */
  2524			delta_adj = HP_MIN - adj_hfp;
  2525			adj_hfp = HP_MIN;
  2526	
  2527			/*
  2528			 * Balance total HBlanking pixel, if HBP does not have enough
  2529			 * space, adjust HSYNC length, otherwise adjust HBP
  2530			 */
  2531			if ((adj_hbp - delta_adj) < HP_MIN)
  2532				/* HBP not enough space */
  2533				adj_hsync -= delta_adj;
  2534			else
  2535				adj_hbp -= delta_adj;
  2536		} else if (adj_hbp < HP_MIN) {
  2537			delta_adj = HP_MIN - adj_hbp;
  2538			adj_hbp = HP_MIN;
  2539	
  2540			/*
  2541			 * Balance total HBlanking pixel, if HBP hasn't enough space,
  2542			 * adjust HSYNC length, otherwize adjust HBP
  2543			 */
  2544			if ((adj_hfp - delta_adj) < HP_MIN)
  2545				/* HFP not enough space */
  2546				adj_hsync -= delta_adj;
  2547			else
  2548				adj_hfp -= delta_adj;
  2549		}
  2550	
  2551	calculate_timing:
  2552	
  2553		dev_dbg(dev, "after mode fixup\n");
  2554		dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
  2555			adj_hsync, adj_hfp, adj_hbp, adj->clock);
  2556	
  2557		/* Reconstruct timing */
  2558		adj->hsync_start = adj->hdisplay + adj_hfp;
  2559		adj->hsync_end = adj->hsync_start + adj_hsync;
  2560		adj->htotal = adj->hsync_end + adj_hbp;
  2561		if (mode->clock > DSC_PIXEL_CLOCK)
> 2562			adj->clock = (u64)vref * adj->htotal * adj->vtotal / 1000 / 1000;
  2563	
  2564		dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
  2565			adj->hsync_start, adj->hsync_end, adj->htotal, adj->clock);
  2566	
  2567		return true;
  2568	}
  2569
kernel test robot Feb. 14, 2025, 10:31 p.m. UTC | #9
Hi Xin,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on drm-misc/drm-misc-next v6.14-rc2 next-20250214]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Xin-Ji/drm-bridge-anx7625-Enable-DSC-feature/20250213-203558
base:   linus/master
patch link:    https://lore.kernel.org/r/20250213123331.3016824-1-xji%40analogixsemi.com
patch subject: [PATCH] drm/bridge:anx7625: Enable DSC feature
config: i386-buildonly-randconfig-004-20250215 (https://download.01.org/0day-ci/archive/20250215/202502150643.fDWGayDK-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250215/202502150643.fDWGayDK-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502150643.fDWGayDK-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: drivers/gpu/drm/bridge/analogix/anx7625.o: in function `anx7625_bridge_mode_fixup':
>> drivers/gpu/drm/bridge/analogix/anx7625.c:2562: undefined reference to `__udivdi3'
>> ld: drivers/gpu/drm/bridge/analogix/anx7625.c:2472: undefined reference to `__udivdi3'


vim +2562 drivers/gpu/drm/bridge/analogix/anx7625.c

  2440	
  2441	static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
  2442					      const struct drm_display_mode *mode,
  2443					      struct drm_display_mode *adj)
  2444	{
  2445		struct anx7625_data *ctx = bridge_to_anx7625(bridge);
  2446		struct device *dev = ctx->dev;
  2447		u32 hsync, hfp, hbp, hblanking;
  2448		u32 adj_hsync, adj_hfp, adj_hbp, adj_hblanking, delta_adj;
  2449		u32 vref, adj_clock;
  2450	
  2451		DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
  2452	
  2453		hsync = mode->hsync_end - mode->hsync_start;
  2454		hfp = mode->hsync_start - mode->hdisplay;
  2455		hbp = mode->htotal - mode->hsync_end;
  2456		hblanking = mode->htotal - mode->hdisplay;
  2457	
  2458		dev_dbg(dev, "before mode fixup\n");
  2459		dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
  2460			hsync, hfp, hbp, adj->clock);
  2461		dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
  2462			adj->hsync_start, adj->hsync_end, adj->htotal);
  2463		adj_hfp = hfp;
  2464		adj_hsync = hsync;
  2465		adj_hbp = hbp;
  2466		adj_hblanking = hblanking;
  2467	
  2468		if (mode->clock > DSC_PIXEL_CLOCK) {
  2469			adj_hsync = DSC_HSYNC_LEN;
  2470			adj_hfp = DSC_HFP_LEN;
  2471			adj_hbp = DSC_HBP_LEN;
> 2472			vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
  2473			goto calculate_timing;
  2474		}
  2475	
  2476		/* No need fixup for external monitor */
  2477		if (!ctx->pdata.panel_bridge)
  2478			return true;
  2479	
  2480		/* HFP needs to be even */
  2481		if (hfp & 0x1) {
  2482			adj_hfp += 1;
  2483			adj_hblanking += 1;
  2484		}
  2485	
  2486		/* HBP needs to be even */
  2487		if (hbp & 0x1) {
  2488			adj_hbp -= 1;
  2489			adj_hblanking -= 1;
  2490		}
  2491	
  2492		/* HSYNC needs to be even */
  2493		if (hsync & 0x1) {
  2494			if (adj_hblanking < hblanking)
  2495				adj_hsync += 1;
  2496			else
  2497				adj_hsync -= 1;
  2498		}
  2499	
  2500		/*
  2501		 * Once illegal timing detected, use default HFP, HSYNC, HBP
  2502		 * This adjusting made for built-in eDP panel, for the externel
  2503		 * DP monitor, may need return false.
  2504		 */
  2505		if (hblanking < HBLANKING_MIN || (hfp < HP_MIN && hbp < HP_MIN)) {
  2506			adj_hsync = SYNC_LEN_DEF;
  2507			adj_hfp = HFP_HBP_DEF;
  2508			adj_hbp = HFP_HBP_DEF;
  2509			vref = adj->clock * 1000 / (adj->htotal * adj->vtotal);
  2510			if (hblanking < HBLANKING_MIN) {
  2511				delta_adj = HBLANKING_MIN - hblanking;
  2512				adj_clock = vref * delta_adj * adj->vtotal;
  2513				adj->clock += DIV_ROUND_UP(adj_clock, 1000);
  2514			} else {
  2515				delta_adj = hblanking - HBLANKING_MIN;
  2516				adj_clock = vref * delta_adj * adj->vtotal;
  2517				adj->clock -= DIV_ROUND_UP(adj_clock, 1000);
  2518			}
  2519	
  2520			DRM_WARN("illegal hblanking timing, use default.\n");
  2521			DRM_WARN("hfp(%d), hbp(%d), hsync(%d).\n", hfp, hbp, hsync);
  2522		} else if (adj_hfp < HP_MIN) {
  2523			/* Adjust hfp if hfp less than HP_MIN */
  2524			delta_adj = HP_MIN - adj_hfp;
  2525			adj_hfp = HP_MIN;
  2526	
  2527			/*
  2528			 * Balance total HBlanking pixel, if HBP does not have enough
  2529			 * space, adjust HSYNC length, otherwise adjust HBP
  2530			 */
  2531			if ((adj_hbp - delta_adj) < HP_MIN)
  2532				/* HBP not enough space */
  2533				adj_hsync -= delta_adj;
  2534			else
  2535				adj_hbp -= delta_adj;
  2536		} else if (adj_hbp < HP_MIN) {
  2537			delta_adj = HP_MIN - adj_hbp;
  2538			adj_hbp = HP_MIN;
  2539	
  2540			/*
  2541			 * Balance total HBlanking pixel, if HBP hasn't enough space,
  2542			 * adjust HSYNC length, otherwize adjust HBP
  2543			 */
  2544			if ((adj_hfp - delta_adj) < HP_MIN)
  2545				/* HFP not enough space */
  2546				adj_hsync -= delta_adj;
  2547			else
  2548				adj_hfp -= delta_adj;
  2549		}
  2550	
  2551	calculate_timing:
  2552	
  2553		dev_dbg(dev, "after mode fixup\n");
  2554		dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
  2555			adj_hsync, adj_hfp, adj_hbp, adj->clock);
  2556	
  2557		/* Reconstruct timing */
  2558		adj->hsync_start = adj->hdisplay + adj_hfp;
  2559		adj->hsync_end = adj->hsync_start + adj_hsync;
  2560		adj->htotal = adj->hsync_end + adj_hbp;
  2561		if (mode->clock > DSC_PIXEL_CLOCK)
> 2562			adj->clock = (u64)vref * adj->htotal * adj->vtotal / 1000 / 1000;
  2563	
  2564		dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
  2565			adj->hsync_start, adj->hsync_end, adj->htotal, adj->clock);
  2566	
  2567		return true;
  2568	}
  2569
Xin Ji Feb. 17, 2025, 1:34 p.m. UTC | #10
> > > > > > > From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > > > > > Sent: Thursday, February 13, 2025 9:04 PM
> > > > > > > To: Xin Ji <xji@analogixsemi.com>
> > > > > > > Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong
> > > > > > > <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>;
> > > > > > > Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas
> > > > > > > Karlman <jonas@kwiboo.se>; Jernej Skrabec
> > > > > > > <jernej.skrabec@gmail.com>; Maarten Lankhorst
> > > > > > > <maarten.lankhorst@linux.intel.com>; Maxime Ripard
> > > > > > > <mripard@kernel.org>; Thomas Zimmermann
> > > > > > > <tzimmermann@suse.de>;
> > > > > David
> > > > > > > Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>;
> > > > > > > Bernie Liang <bliang@analogixsemi.com>; Qilin Wen
> > > > > > > <qwen@analogixsemi.com>; treapking@google.com;
> > > > > > > dri-devel@lists.freedesktop.org; linux-
> > > > > > > kernel@vger.kernel.org
> > > > > > > Subject: Re: [PATCH] drm/bridge:anx7625: Enable DSC feature
> > > > >
> > > > > PLease remove such splats, use something more sensible.
> > > > OK, I'll change the subject
> > >
> > > It's not about the subject. Compare just "ABC DEF wrote:" and your
> > > quatation header.
> > Sorry, these message is automatically added by Outlook, I'll remove it.
> > >
> > > > >
> > > > > > >
> > > > > > >
> > > > > > > On Thu, Feb 13, 2025 at 08:33:30PM +0800, Xin Ji wrote:
> > > > > > > > As anx7625 MIPI RX bandwidth(maximum 1.5Gbps per lane) and
> > > > > > > > internal pixel clock(maximum 300M) limitation. Anx7625
> > > > > > > > must enable DSC feature while MIPI source want to output 4K30
> resolution.
> > > > > > >
> > > > > > > This commit message is pretty hard to read and understand
> > > > > > > for a non-native speaker. Please consider rewriting it so
> > > > > > > that it is easier to
> > > > > understand it.
> > > > > > >
> > > > > > Thanks for the review, sorry about that, I'll rewriting the
> > > > > > commit message
> > > > > > > >
> > > > > > > > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > > > > > > > ---
> > > > > > > >  drivers/gpu/drm/bridge/analogix/anx7625.c | 300
> > > > > > > > ++++++++++++++++++----
> > > > > > > > ++++++++++++++++++drivers/gpu/drm/bridge/analogix/anx7625.
> > > > > > > > ++++++++++++++++++h
> > > > > > > > ++++++++++++++++++|
> > > > > > > > 32 +++
> > > > > > > >  2 files changed, 284 insertions(+), 48 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > > index 4be34d5c7a3b..7d86ab02f71c 100644
> > > > > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > > > > > > > @@ -22,6 +22,7 @@
> > > > > > > >
> > > > > > > >  #include <drm/display/drm_dp_aux_bus.h>  #include
> > > > > > > > <drm/display/drm_dp_helper.h>
> > > > > > > > +#include <drm/display/drm_dsc_helper.h>
> > > > > > > >  #include <drm/display/drm_hdcp_helper.h>  #include
> > > > > > > > <drm/drm_atomic_helper.h>  #include <drm/drm_bridge.h> @@
> > > > > > > > -476,6
> > > > > > > > +477,138 @@ static int anx7625_set_k_value(struct
> > > > > > > > +anx7625_data
> > > > > > > > +*ctx)
> > > > > > > >                                MIPI_DIGITAL_ADJ_1, 0x3D);
> > > > > > > > }
> > > > > > > >
> > > > > > > > +static int anx7625_set_dsc_params(struct anx7625_data *ctx) {
> > > > > > > > +     int ret, i;
> > > > > > > > +     u16 htotal, vtotal;
> > > > > > > > +
> > > > > > > > +     if (!ctx->dsc_en)
> > > > > > > > +             return 0;
> > > > > > > > +
> > > > > > > > +     /* Htotal */
> > > > > > > > +     htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > > > > +             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > > > +     ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                             HORIZONTAL_TOTAL_PIXELS_L, htotal);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > > > > +     /* Hactive */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_ACTIVE_PIXELS_L,
> > > > > > > > +                              ctx->dt.hactive.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > > > > +                              ctx->dt.hactive.min >> 8);
> > > > > > > > +     /* HFP */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_FRONT_PORCH_L,
> > > > > > > > +                              ctx->dt.hfront_porch.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_FRONT_PORCH_H,
> > > > > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > > > > +     /* HWS */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_SYNC_WIDTH_L,
> > > > > > > > +                              ctx->dt.hsync_len.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_SYNC_WIDTH_H,
> > > > > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > > > > +     /* HBP */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_BACK_PORCH_L,
> > > > > > > > +                              ctx->dt.hback_porch.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              HORIZONTAL_BACK_PORCH_H,
> > > > > > > > +                              ctx->dt.hback_porch.min >> 8);
> > > > > > > > +     /* Vtotal */
> > > > > > > > +     vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
> > > > > > > > +              ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > TOTAL_LINES_L,
> > > > > > > > +                              vtotal);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > TOTAL_LINES_H,
> > > > > > > > +                              vtotal >> 8);
> > > > > > > > +     /* Vactive */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > ACTIVE_LINES_L,
> > > > > > > > +                              ctx->dt.vactive.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > ACTIVE_LINES_H,
> > > > > > > > +                              ctx->dt.vactive.min >> 8);
> > > > > > > > +     /* VFP */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              VERTICAL_FRONT_PORCH, ctx-
> >dt.vfront_porch.min);
> > > > > > > > +     /* VWS */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> > > > > > > > +     /* VBP */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> > > > > > > > +                              VERTICAL_BACK_PORCH,
> > > > > > > > + ctx->dt.vback_porch.min);
> > > > > > >
> > > > > > > This code mostly duplicates
> > > > > > > anx7625_dsi_video_timing_config() with the I2C client being
> > > > > > > the only difference. Please consider extracting a common helper to
> write the timings.
> > > > > > It is hard to extracting a common helper, they are used
> > > > > > different I2C slave address and timing register need divided by 3 if DSC
> enabled.
> > > > >
> > > > > I2C client can be a parameter. Also please comment whether /3 is
> > > > > because of bpp/bpc ratio or due to some other reason?
> > > > >
> > > > > Does anx7625 support any mode other than 8bpp / 8bpc?
> > > > I'll try to make a common function, anx7625 mipi only support
> > > > RGB888. DSC
> > > 8bpp.
> > > > /3 is because of DSC ration 1:3.
> > >
> > > Please add this to the commit message, add a comment next to the
> > > corresponding #define and use it instead of /3 all over the place.
> > OK
> > >
> > > > >
> > > > > > >
> > > > > > > > +
> > > > > > > > +     /* Htotal */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > TOTAL_PIXEL_L_7E,
> > > > > > > > +                              htotal);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > TOTAL_PIXEL_H_7E,
> > > > > > > > +                              htotal >> 8);
> > > > > > > > +     /* Hactive */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
> > > > > > > > +     /* HFP */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              HORIZON_FRONT_PORCH_L_7E,
> > > > > > > > +                              ctx->dt.hfront_porch.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              HORIZON_FRONT_PORCH_H_7E,
> > > > > > > > +                              ctx->dt.hfront_porch.min >> 8);
> > > > > > > > +     /* HWS */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              HORIZON_SYNC_WIDTH_L_7E,
> > > > > > > > +                              ctx->dt.hsync_len.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              HORIZON_SYNC_WIDTH_H_7E,
> > > > > > > > +                              ctx->dt.hsync_len.min >> 8);
> > > > > > > > +     /* HBP */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              HORIZON_BACK_PORCH_L_7E,
> > > > > > > > +                              ctx->dt.hback_porch.min);
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                              HORIZON_BACK_PORCH_H_7E,
> > > > > > > > +                              ctx->dt.hback_porch.min >>
> > > > > > > > + 8);
> > > > > > > > +
> > > > > > > > +     /* Config DSC decoder internal blank timing for decoder to start
> */
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > > > > +                              H_BLANK_L,
> > > > > > > > +                              dsc_div(htotal - ctx->dt.hactive.min));
> > > > > > > > +     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> > > > > > > > +                              H_BLANK_H,
> > > > > > > > +                              dsc_div(htotal -
> > > > > > > > + ctx->dt.hactive.min)
> > > > > > > > + >> 8);
> > > > > > > > +
> > > > > > > > +     /* Compress ratio  RATIO bit[7:6] */
> > > > > > > > +     ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > + R_I2C_1,
> > > 0x3F);
> > > > > > > > +     ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
> > > > > > > > +                             (5 - DSC_COMPRESS_RATIO) << 6);
> > > > > > > > +     /*PPS table*/
> > > > > > > > +     for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
> > > > > > > > +             ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                                            R_PPS_REG_0 +
> > > > > > > > + i, PPS_BLOCK_SIZE,
> > > > > > > > +
> > > > > > > > + &ctx->pps_table[i]);
> > > > > > > > +
> > > > > > > > +     return ret;
> > > > > > > > +}
> > > > > > > > +
> > > > > > > > +static int anx7625_timing_write(struct anx7625_data *ctx,
> > > > > > > > +                             struct i2c_client *client,
> > > > > > > > +                             u8 reg_addr, u16 reg_val,
> > > > > > > > +bool
> > > > > > > > +high_byte) {
> > > > > > > > +     u8 reg_data;
> > > > > > > > +
> > > > > > > > +     if (ctx->dsc_en)
> > > > > > > > +             reg_val = dsc_div(reg_val);
> > > > > > > > +
> > > > > > > > +     reg_data = (high_byte ? (reg_val >> 8) : reg_val) &
> > > > > > > > + 0xFF;
> > > > > > > > +
> > > > > > > > +     return anx7625_reg_write(ctx, client, reg_addr,
> > > > > > > > + reg_data); }
> > > > > > >
> > > > > > > Ugh, no. Calculate htotal in the calling function and call
> > > > > > > anx7625_reg_write() as you were doing that before.
> > > > > > >
> > > > > > anx7625_timing_write() is a common function, it was called
> > > > > > many times, so we cannot calculate htotal in it.
> > > > >
> > > > > On the caller side. I'd suggest to inline anx7625_timing_write()
> > > > > to make the code more explicit.
> > > > OK.
> > > > >
> > > > > >
> > > > > > > > +
> > > > > > > >  static int anx7625_dsi_video_timing_config(struct
> > > > > > > > anx7625_data
> > > > > > > > *ctx) {
> > > > > > > >       struct device *dev = ctx->dev; @@ -506,34 +639,33 @@
> > > > > > > > static int anx7625_dsi_video_timing_config(struct
> > > > > > > anx7625_data *ctx)
> > > > > > > >       ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> > > > > > > >                               MIPI_LANE_CTRL_0,
> > > > > > > > ctx->pdata.mipi_lanes
> > > > > > > > - 1);
> > > > > > > >
> > > > > > > > -     /* Htotal */
> > > > > > > >       htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> > > > > > > > -             ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> > > > > > > > +                      ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> > > > > > > > +     /* Htotal */
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_TOTAL_PIXELS_H, htotal,
> > > > > > > > + true);
> > > > > > > >       /* Hactive */
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min &
> > > 0xFF);
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >>
> 8);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_ACTIVE_PIXELS_L,
> > > > > > > > + ctx->dt.hactive.min,
> > > false);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_ACTIVE_PIXELS_H,
> > > > > > > > + ctx->dt.hactive.min, true);
> > > > > > > >       /* HFP */
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_FRONT_PORCH_L, ctx-
> > > >dt.hfront_porch.min);
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_FRONT_PORCH_H,
> > > > > > > > -                     ctx->dt.hfront_porch.min >> 8);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_FRONT_PORCH_L,
> > > > > > > > + ctx->dt.hfront_porch.min,
> > > > > false);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_FRONT_PORCH_H,
> > > > > > > > + ctx->dt.hfront_porch.min, true);
> > > > > > >
> > > > > > > Are porches also compressed? I think blanking signal timings
> > > > > > > are transferred as is, without compression.
> > > > > > Porches not be compressed, anx7625 internal digital block will
> > > > > > multiply by 3 while enable DSC feature, so the register must divided by 3.
> > > > >
> > > > > Ack
> > > > >
> > > > > > >
> > > > > > > >       /* HWS */
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_SYNC_WIDTH_H, ctx-
> >dt.hsync_len.min >>
> > > 8);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_SYNC_WIDTH_L,
> > > > > > > > + ctx->dt.hsync_len.min,
> > > false);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_SYNC_WIDTH_H,
> > > > > > > > + ctx->dt.hsync_len.min, true);
> > > > > > > >       /* HBP */
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_BACK_PORCH_L, ctx-
> >dt.hback_porch.min);
> > > > > > > > -     ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > -                     HORIZONTAL_BACK_PORCH_H, ctx-
> >dt.hback_porch.min >>
> > > 8);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_BACK_PORCH_L,
> > > > > > > > + ctx->dt.hback_porch.min,
> > > > > false);
> > > > > > > > +     ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
> > > > > > > > +                     HORIZONTAL_BACK_PORCH_H,
> > > > > > > > + ctx->dt.hback_porch.min, true);
> > > > > > > >       /* Vactive */
> > > > > > > >       ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> > > ACTIVE_LINES_L,
> > > > > > > >                       ctx->dt.vactive.min); @@ -663,9
> > > > > > > > +795,15 @@ static int anx7625_dsi_config(struct
> > > > > > > > anx7625_data *ctx)
> > > > > > > >
> > > > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> > > > > > > >
> > > > > > > > -     /* DSC disable */
> > > > > > > > -     ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > -                             R_DSC_CTRL_0, ~DSC_EN);
> > > > > > > > +     ret = anx7625_set_dsc_params(ctx);
> > > > > > > > +     if (ctx->dsc_en)
> > > > > > > > +             /* DSC enable */
> > > > > > > > +             ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                                     R_DSC_CTRL_0, DSC_EN);
> > > > > > > > +     else
> > > > > > > > +             /* DSC disable */
> > > > > > > > +             ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> > > > > > > > +                                      R_DSC_CTRL_0,
> > > > > > > > + ~DSC_EN);
> > > > > > > >
> > > > > > > >       ret |= anx7625_api_dsi_config(ctx);
> > > > > > > >
> > > > > > > > @@ -2083,6 +2221,7 @@ static int
> > > > > > > > anx7625_setup_dsi_device(struct
> > > > > > > anx7625_data *ctx)
> > > > > > > >               MIPI_DSI_MODE_VIDEO_HSE |
> > > > > > > >               MIPI_DSI_HS_PKT_END_ALIGNED;
> > > > > > > >
> > > > > > > > +     dsi->dsc = &ctx->dsc;
> > > > > > > >       ctx->dsi = dsi;
> > > > > > > >
> > > > > > > >       return 0;
> > > > > > > > @@ -2186,20 +2325,68 @@ anx7625_bridge_mode_valid(struct
> > > > > > > > drm_bridge
> > > > > > > *bridge,
> > > > > > > >       struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> > > > > > > >       struct device *dev = ctx->dev;
> > > > > > > >
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> > > > > > > > +     dev_dbg(dev, "drm mode checking\n");
> > > > > > > > +     if (mode->clock > SUPPORT_PIXEL_CLOCK)
> > > > > > > > +             return MODE_CLOCK_HIGH;
> > > > > > > > +
> > > > > > > > +     if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
> > > > > > > > +             return MODE_CLOCK_LOW;
> > > > > > > >
> > > > > > > > -     /* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> > > > > > > > -     if (mode->clock > SUPPORT_PIXEL_CLOCK) {
> > > > > > > > -             DRM_DEV_DEBUG_DRIVER(dev,
> > > > > > > > -                                  "drm mode invalid, pixelclock too high.\n");
> > > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay
> > > > > > > > + % 3 !=
> > > > > > > > + 0))
> > > > > > >
> > > > > > > Magic number 3. Also is it actually required? I think DSC
> > > > > > > standard has no such requirement.
> > > > > > This is anx7625 limitation, if mode->hdisplay cannot be
> > > > > > divided by 3, then display will have overlap/shift issue.
> > > > >
> > > > > Ack, add a comment or extend a commit message please.
> > > > OK, I'll add a comment
> > > > >
> > > > > > >
> > > > > > > >               return MODE_CLOCK_HIGH;
> > > > > > > > -     }
> > > > > > > >
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> > > > > > > > +     dev_dbg(dev, "drm mode valid.\n");
> > > > > > > >
> > > > > > > >       return MODE_OK;
> > > > > > > >  }
> > > > > > > >
> > > > > > > > +static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en)
> {
> > > > > > > > +     int ret;
> > > > > > > > +     struct device *dev = ctx->dev;
> > > > > > > > +
> > > > > > > > +     ctx->dsc_en = en;
> > > > > > > > +
> > > > > > > > +     if (en) {
> > > > > > > > +             ctx->dsc.dsc_version_major = 1;
> > > > > > > > +             ctx->dsc.dsc_version_minor = 1;
> > > > > > > > +             ctx->dsc.slice_height = 8;
> > > > > > > > +             ctx->dsc.slice_width = ctx->dt.hactive.min /
> DSC_SLICE_NUM;
> > > > > > > > +             ctx->dsc.slice_count = DSC_SLICE_NUM;
> > > > > > > > +             ctx->dsc.bits_per_component = 8;
> > > > > > > > +             ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
> > > > > > > > +             ctx->dsc.block_pred_enable = true;
> > > > > > > > +             ctx->dsc.native_420 = false;
> > > > > > > > +             ctx->dsc.native_422 = false;
> > > > > > > > +             ctx->dsc.simple_422 = false;
> > > > > > > > +             ctx->dsc.vbr_enable = false;
> > > > > > > > +             ctx->dsc.rc_model_size =
> > > > > > > > + DSC_RC_MODEL_SIZE_CONST;
> > > > >
> > > > > This one is default, please drop.
> > > > OK
> > > > >
> > > > > > > > +             ctx->dsc.pic_width = ctx->dt.hactive.min;
> > > > > > > > +             ctx->dsc.pic_height = ctx->dt.vactive.min;
> > > > >
> > > > > These two are set on the DSC encoder side.
> > > > OK, I'll remove it
> > > > >
> > > > > > > > +             ctx->dsc.convert_rgb = 1;
> > > > > > > > +             ctx->dsc.vbr_enable = 0;
> > > > > > >
> > > > > > > A lot of this params should be coming from the sink device.
> > > > > > > You have to get them from the DPCD.
> > > > > > These parameter is just MIPI source and anx7625 and used only
> > > > > > for DSC feature,
> > > > > > Anx7625 is bridge IC, sink monitor only receive normal DP
> > > > > > signal from anx7625, sink device didn't know DSC information,
> > > > > > no need read
> > > DPCD.
> > > > >
> > > > > Thanks. From you commit message it is impossible to understand
> > > > > whether DSC happens between the host and your bridge or between
> > > > > the bridge and the monitor.
> > > > I'll add more detail in commit message
> > > > >
> > > > > > >
> > > > > > > > +
> > > > > > > > +             drm_dsc_set_rc_buf_thresh(&ctx->dsc);
> > > > > > > > +             drm_dsc_set_const_params(&ctx->dsc);
> > > > > > > > +
> > > > > > > > +             ctx->dsc.initial_scale_value =
> > > > > > > > + drm_dsc_initial_scale_value(&ctx-
> > > > > >dsc);
> > > > > > > > +             ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component +
> 1;
> > > > > > > > +             ret = drm_dsc_setup_rc_params(&ctx->dsc,
> > > DRM_DSC_1_2_444);
> > > > > > > > +             if (ret < 0)
> > > > > > > > +                     dev_warn(dev,
> > > > > > > > + "drm_dsc_setup_rc_params ret %d\n", ret);
> > > > > > > > +
> > > > > > > > +             drm_dsc_compute_rc_parameters(&ctx->dsc);
> > > > > > >
> > > > > > > You have ignored return value. Please handle the function
> > > > > > > returning an
> > > error.
> > > > > > OK
> > > > >
> > > > > All these functions are to be called on the DSC encoder side as
> > > > > it has to be able to infer DSC params.
> > > >
> > > > I don't know, we co-work with MTK encoder, they need us to initial
> > > > dsc data structure
> > >
> > > As I wrote, encoder should be able to influence some of those
> > > params. As such, DSC decoder should provide some values, then DSC
> > > encoder's .pre_enable should be able to update those values (e.g. by
> > > setting .pic_width and .pic_height and/or disabling some of flags).
> > > Then the DSC encoder should fill the rest of the params by calling all these
> functions. Consider how drm/msm/dsi handles it.
> > OK, I'll check it.
> > >
> > > >
> > > > >
> > > > > > >
> > > > > > > > +
> > > > > > > > +             drm_dsc_pps_payload_pack((struct
> > > > > > > > + drm_dsc_picture_parameter_set
> > > > > > > *)&ctx->pps_table,
> > > > > > > > +                                      &ctx->dsc);
> > > > > > > > +             dev_dbg(dev, "anx7625 enable dsc\n");
> > > > > > > > +     } else {
> > > > > > > > +             ctx->dsc.dsc_version_major = 0;
> > > > > > > > +             ctx->dsc.dsc_version_minor = 0;
> > > > > > > > +             dev_dbg(dev, "anx7625 disable dsc\n");
> > > > > > > > +     }
> > > > > > > > +}
> > > > > > > > +
> > > > > > > >  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> > > > > > > >                                   const struct drm_display_mode *old_mode,
> > > > > > > >                                   const struct
> > > > > > > > drm_display_mode
> > > > > > > > *mode) @@ -2244,6 +2431,11 @@ static void
> > > > > > > > anx7625_bridge_mode_set(struct
> > > > > > > drm_bridge *bridge,
> > > > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> > > > > > > >                            mode->vsync_end,
> > > > > > > >                            mode->vtotal);
> > > > > > > > +
> > > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > > > >
> > > > > > > What if the sink doesn't support DSC? The decision whether
> > > > > > > to enable DSC or not should be happening in the atomic_check().
> > > > > > > Likewise mode_valid should be able to check if your bridge
> > > > > > > and the sink can agree on DSC params and reject modes if they can
> not.
> > > > > > Anx7625 is bridge IC, it receive MIPI data and DP output, DSC
> > > > > > only exist between SOC and Anx7625, sink monitor only receive
> > > > > > normal DP signal from anx7625, there is no compression at DP
> > > > > > output, so no need to
> > > > > check sink device.
> > > > >
> > > > > Well. Then the same question applies in the other direction:
> > > > > what if the host doesnt' support DSC?
> > > > If SOC host doesn't support DSC, then cannot display 4K30,
> > > > currently, only debug with MTK DSI encoder.
> > >
> > > The bridge is a generic driver. So while you test with Mediatek
> > > platforms, you still have to think about a generic case and add necessary
> checks.
> > OK, I'll check it.
> > >
> > > > >
> > > > > > >
> > > > > > > > +             anx7625_dsc_enable(ctx, true);
> > > > > > > > +     else
> > > > > > > > +             anx7625_dsc_enable(ctx, false);
> > > > > > > >  }
> > > > > > > >
> > > > > > > >  static bool anx7625_bridge_mode_fixup(struct drm_bridge
> > > > > > > > *bridge, @@
> > > > > > > > -2258,26 +2450,33 @@ static bool
> > > > > > > > anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
> > > > > > > >
> > > > > > > >       DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
> > > > > > > >
> > > > > > > > -     /* No need fixup for external monitor */
> > > > > > > > -     if (!ctx->pdata.panel_bridge)
> > > > > > > > -             return true;
> > > > > > > > -
> > > > > > > >       hsync = mode->hsync_end - mode->hsync_start;
> > > > > > > >       hfp = mode->hsync_start - mode->hdisplay;
> > > > > > > >       hbp = mode->htotal - mode->hsync_end;
> > > > > > > >       hblanking = mode->htotal - mode->hdisplay;
> > > > > > > >
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > > > > clock(%d)\n",
> > > > > > > > -                          hsync, hfp, hbp, adj->clock);
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d),
> hsync_end(%d),
> > > > > > > htot(%d)\n",
> > > > > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > > > > -
> > > > > > > > +     dev_dbg(dev, "before mode fixup\n");
> > > > > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > > > > +             hsync, hfp, hbp, adj->clock);
> > > > > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
> > > > > > > > +             adj->hsync_start, adj->hsync_end,
> > > > > > > > + adj->htotal);
> > > > > > >
> > > > > > > No. Please use drm_dbg_driver(), but not dev_dbg(). And
> > > > > > > anyway, this should go to a separate commit.
> > > > > > OK, I'll not change it in this patch.
> > > > > > >
> > > > > > > >       adj_hfp = hfp;
> > > > > > > >       adj_hsync = hsync;
> > > > > > > >       adj_hbp = hbp;
> > > > > > > >       adj_hblanking = hblanking;
> > > > > > > >
> > > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK) {
> > > > > > > > +             adj_hsync = DSC_HSYNC_LEN;
> > > > > > > > +             adj_hfp = DSC_HFP_LEN;
> > > > > > > > +             adj_hbp = DSC_HBP_LEN;
> > > > > > > > +             vref = (u64)adj->clock * 1000 * 1000 /
> > > > > > > > + (adj->htotal * adj-
> > > >vtotal);
> > > > > > > > +             goto calculate_timing;
> > > > > > > > +     }
> > > > > > > > +
> > > > > > > > +     /* No need fixup for external monitor */
> > > > > > > > +     if (!ctx->pdata.panel_bridge)
> > > > > > > > +             return true;
> > > > > > > > +
> > > > > > > >       /* HFP needs to be even */
> > > > > > > >       if (hfp & 0x1) {
> > > > > > > >               adj_hfp += 1; @@ -2349,16 +2548,21 @@ static
> > > > > > > > bool anx7625_bridge_mode_fixup(struct
> > > > > > > drm_bridge *bridge,
> > > > > > > >                       adj_hfp -= delta_adj;
> > > > > > > >       }
> > > > > > > >
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d),
> > > > > > > clock(%d)\n",
> > > > > > > > -                          adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > > > > +calculate_timing:
> > > > > > > > +
> > > > > > > > +     dev_dbg(dev, "after mode fixup\n");
> > > > > > > > +     dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
> > > > > > > > +             adj_hsync, adj_hfp, adj_hbp, adj->clock);
> > > > > > > >
> > > > > > > >       /* Reconstruct timing */
> > > > > > > >       adj->hsync_start = adj->hdisplay + adj_hfp;
> > > > > > > >       adj->hsync_end = adj->hsync_start + adj_hsync;
> > > > > > > >       adj->htotal = adj->hsync_end + adj_hbp;
> > > > > > > > -     DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d),
> hsync_end(%d),
> > > > > > > htot(%d)\n",
> > > > > > > > -                          adj->hsync_start, adj->hsync_end, adj->htotal);
> > > > > > > > +     if (mode->clock > DSC_PIXEL_CLOCK)
> > > > > > > > +             adj->clock = (u64)vref * adj->htotal *
> > > > > > > > + adj->vtotal /
> > > > > > > > + 1000 / 1000;
> > > > > > > > +
> > > > > > > > +     dev_dbg(dev, "hsync_start(%d), hsync_end(%d),
> > > > > > > > + htot(%d),
> > > clock(%d)\n",
> > > > > > > > +             adj->hsync_start, adj->hsync_end,
> > > > > > > > + adj->htotal,
> > > > > > > > + adj->clock);
> > > > > > > >
> > > > > > > >       return true;
> > > > > > > >  }
> > > > > > > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > > b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > > index eb5580f1ab2f..db931f5800b1 100644
> > > > > > > > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > > > > > > > @@ -149,6 +149,8 @@
> > > > > > > >  #define HFP_HBP_DEF          ((HBLANKING_MIN - SYNC_LEN_DEF) /
> 2)
> > > > > > > >  #define VIDEO_CONTROL_0      0x08
> > > > > > > >
> > > > > > > > +#define  TOTAL_LINES_L          0x12
> > > > > > > > +#define  TOTAL_LINES_H          0x13
> > > > > > > >  #define  ACTIVE_LINES_L         0x14
> > > > > > > >  #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
> > > > > > > >  #define  VERTICAL_FRONT_PORCH   0x16
> > > > > > > > @@ -166,6 +168,32 @@
> > > > > > > >  #define  HORIZONTAL_BACK_PORCH_L      0x21
> > > > > > > >  #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are
> > > reserved
> > > > > */
> > > > > > > >
> > > > > > > > +#define  H_BLANK_L                    0x3E
> > > > > > > > +#define  H_BLANK_H                    0x3F
> > > > > > > > +#define  DSC_COMPRESS_RATIO           3
> > > > > > > > +#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
> > > > > > >
> > > > > > > This assumes 1:3 ratio. Does anx7625 support only 8bpp / 8bpc mode?
> > > > > > > Or does
> > > > > > > 1:3 come from some other ratio?
> > > > > > We only tested 1:3 compression ratio, 24bpp compress to 8bpp.
> > > > >
> > > > > What are hardware limitations?
> > > > Anx7625 MIPI only support RGB888 24bpp. With DSC 3:1 compression,
> > > > MIPI TX output 8bpp.
> > >
> > > As I wrote, a comment please.
> > OK
> > >
> > > > >
> > > > > > >
> > > > > > > > +#define  DSC_SLICE_NUM                2
> > > > > > > > +#define  DSC_PIXEL_CLOCK              250000
> > > > > > > > +#define  DSC_HSYNC_LEN                90
> > > > > > > > +#define  DSC_HFP_LEN                  177
> > > > > > > > +#define  DSC_HBP_LEN                  297
> > > > > > > > +
> > > > > > > > +#define  TOTAL_PIXEL_L_7E             0x50
> > > > > > > > +#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved
> */
> > > > > > > > +#define  ACTIVE_PIXEL_L_7E            0x52
> > > > > > > > +#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved
> */
> > > > > > > > +#define  HORIZON_FRONT_PORCH_L_7E     0x54
> > > > > > > > +#define  HORIZON_FRONT_PORCH_H_7E     0x55
> > > > > > > > +#define  HORIZON_SYNC_WIDTH_L_7E      0x56
> > > > > > > > +#define  HORIZON_SYNC_WIDTH_H_7E      0x57
> > > > > > > > +#define  HORIZON_BACK_PORCH_L_7E      0x58
> > > > > > > > +#define  HORIZON_BACK_PORCH_H_7E      0x59
> > > > > > > > +
> > > > > > > > +#define  PPS_SIZE                     128
> > > > > > > > +#define  PPS_BLOCK_SIZE               32
> > > > > > > > +#define  R_PPS_REG_0                  0x80
> > > > > > > > +#define  R_I2C_1                      0x81
> > > > > > > > +
> > > > > > > >  /******** END of I2C Address 0x72 *********/
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> /***************************************************************/
> > > > > > > > @@ -415,6 +443,7 @@ enum audio_wd_len {
> > > > > > > >  #define MAX_EDID_BLOCK       3
> > > > > > > >  #define EDID_TRY_CNT 3
> > > > > > > >  #define SUPPORT_PIXEL_CLOCK  300000
> > > > > > > > +#define SUPPORT_MIN_PIXEL_CLOCK      50000
> > > > > > > >
> > > > > > > >  /***************** Display End *****************/
> > > > > > > >
> > > > > > > > @@ -454,6 +483,7 @@ struct anx7625_data {
> > > > > > > >       int hpd_high_cnt;
> > > > > > > >       int dp_en;
> > > > > > > >       int hdcp_cp;
> > > > > > > > +     bool dsc_en;
> > > > > > > >       /* Lock for work queue */
> > > > > > > >       struct mutex lock;
> > > > > > > >       struct device *dev;
> > > > > > > > @@ -479,6 +509,8 @@ struct anx7625_data {
> > > > > > > >       struct drm_connector *connector;
> > > > > > > >       struct mipi_dsi_device *dsi;
> > > > > > > >       struct drm_dp_aux aux;
> > > > > > > > +     struct drm_dsc_config dsc;
> > > > > > > > +     char pps_table[PPS_SIZE];
> > > > > > >
> > > > > > > pps_table and drm_dsc_config can vary depending on the mode
> > > > > > > and connected sink. THey should be a part of the atomic
> > > > > > > state rather than a long-living anx7625_data. So does dsc_en.
> > > > > > No need to check sink monitor, because DSC only exist between
> > > > > > SOC and Anx7625, sink monitor only receive normal DP signal from
> anx7625.
> > > > > > Anx7625 is responsible for decompression.
> > > > >
> > > > > The same way, they depend on the selected video mode, don't they?
> > > > Actually it depends on pixel clock, if it is more than 250M, then need to do
> DSC.
> > >
> > > Yes. So you should check if you can enable DSC in .atomic_check()
> > > and set dsc_en correspondingly. At the same time in .atomic_check()
> > > you can not modify anx7625_data as it is a check time, commit can be
> > > rejected or it can be a test- only check. So dsc_en should go to
> drm_bridge_state-wrapping structure.
> > >
> > > At the same time I don't see a value in storing the packed PPS
> > > table, it is a short- lived data.
> > Do you mean we can maintain dsc_en flag for each timing/resolution in
> > drm_bridge_state structure, and set it in .atomic_check(), and check
> > the drm_bridge_state's  dsc_en  in .atomic_enable()? I don't know how to
> make a drm_bridge_state-wrapping structure.
> 
> Ideally yes. You should define
>   struct anx7625_bridge_state {
>     struct drm_bridge_state base;
>     bool dsc_en;
>   };
> 
> Then define your own versions of atomic_reset and .atomic_duplicate_state
> callbacks.
> 
> Note, we currently don't have a way to check that the DSI host actually supports
> DSC, you have to invent it.
> 

OK, got it, I'll try it and discuss with related people, thanks!

> >
> > Based on the design, anx7625 chip needs 128 bytes pps table, without
> > it, chip cannot decompress DSC data.
> 
> Yes, that's clear. But it doesn't have to be a part of the anx7625_data.
> Allocate it on stack, fill it, program it, forget it.
OK

> 
> > >
> > > > >
> > > > > > >
> > > > > > > >  };
> > > > > > > >
> > > > > > > >  #endif  /* __ANX7625_H__ */
> > > > > > > > --
> > > > > > > > 2.25.1
> > > > > > > >
> > > > > > >
> > > > > > > --
> > > > > > > With best wishes
> > > > > > > Dmitry
> > > > >
> > > > > --
> > > > > With best wishes
> > > > > Dmitry
> > >
> > > --
> > > With best wishes
> > > Dmitry
> 
> --
> With best wishes
> Dmitry
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 4be34d5c7a3b..7d86ab02f71c 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -22,6 +22,7 @@ 
 
 #include <drm/display/drm_dp_aux_bus.h>
 #include <drm/display/drm_dp_helper.h>
+#include <drm/display/drm_dsc_helper.h>
 #include <drm/display/drm_hdcp_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
@@ -476,6 +477,138 @@  static int anx7625_set_k_value(struct anx7625_data *ctx)
 				 MIPI_DIGITAL_ADJ_1, 0x3D);
 }
 
+static int anx7625_set_dsc_params(struct anx7625_data *ctx)
+{
+	int ret, i;
+	u16 htotal, vtotal;
+
+	if (!ctx->dsc_en)
+		return 0;
+
+	/* Htotal */
+	htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
+		ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
+	ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				HORIZONTAL_TOTAL_PIXELS_L, htotal);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
+	/* Hactive */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_ACTIVE_PIXELS_L,
+				 ctx->dt.hactive.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_ACTIVE_PIXELS_H,
+				 ctx->dt.hactive.min >> 8);
+	/* HFP */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_FRONT_PORCH_L,
+				 ctx->dt.hfront_porch.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_FRONT_PORCH_H,
+				 ctx->dt.hfront_porch.min >> 8);
+	/* HWS */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_SYNC_WIDTH_L,
+				 ctx->dt.hsync_len.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_SYNC_WIDTH_H,
+				 ctx->dt.hsync_len.min >> 8);
+	/* HBP */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_BACK_PORCH_L,
+				 ctx->dt.hback_porch.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 HORIZONTAL_BACK_PORCH_H,
+				 ctx->dt.hback_porch.min >> 8);
+	/* Vtotal */
+	vtotal = ctx->dt.vactive.min + ctx->dt.vfront_porch.min +
+		 ctx->dt.vback_porch.min + ctx->dt.vsync_len.min;
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_L,
+				 vtotal);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, TOTAL_LINES_H,
+				 vtotal >> 8);
+	/* Vactive */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_L,
+				 ctx->dt.vactive.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client, ACTIVE_LINES_H,
+				 ctx->dt.vactive.min >> 8);
+	/* VFP */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
+	/* VWS */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
+	/* VBP */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
+				 VERTICAL_BACK_PORCH, ctx->dt.vback_porch.min);
+
+	/* Htotal */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_L_7E,
+				 htotal);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, TOTAL_PIXEL_H_7E,
+				 htotal >> 8);
+	/* Hactive */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 ACTIVE_PIXEL_L_7E, ctx->dt.hactive.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 ACTIVE_PIXEL_H_7E, ctx->dt.hactive.min >> 8);
+	/* HFP */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 HORIZON_FRONT_PORCH_L_7E,
+				 ctx->dt.hfront_porch.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 HORIZON_FRONT_PORCH_H_7E,
+				 ctx->dt.hfront_porch.min >> 8);
+	/* HWS */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 HORIZON_SYNC_WIDTH_L_7E,
+				 ctx->dt.hsync_len.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 HORIZON_SYNC_WIDTH_H_7E,
+				 ctx->dt.hsync_len.min >> 8);
+	/* HBP */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 HORIZON_BACK_PORCH_L_7E,
+				 ctx->dt.hback_porch.min);
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
+				 HORIZON_BACK_PORCH_H_7E,
+				 ctx->dt.hback_porch.min >> 8);
+
+	/* Config DSC decoder internal blank timing for decoder to start */
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
+				 H_BLANK_L,
+				 dsc_div(htotal - ctx->dt.hactive.min));
+	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
+				 H_BLANK_H,
+				 dsc_div(htotal - ctx->dt.hactive.min) >> 8);
+
+	/* Compress ratio  RATIO bit[7:6] */
+	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client, R_I2C_1, 0x3F);
+	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, R_I2C_1,
+				(5 - DSC_COMPRESS_RATIO) << 6);
+	/*PPS table*/
+	for (i = 0; i < PPS_SIZE; i += PPS_BLOCK_SIZE)
+		ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p2_client,
+					       R_PPS_REG_0 + i, PPS_BLOCK_SIZE,
+					       &ctx->pps_table[i]);
+
+	return ret;
+}
+
+static int anx7625_timing_write(struct anx7625_data *ctx,
+				struct i2c_client *client,
+				u8 reg_addr, u16 reg_val, bool high_byte)
+{
+	u8 reg_data;
+
+	if (ctx->dsc_en)
+		reg_val = dsc_div(reg_val);
+
+	reg_data = (high_byte ? (reg_val >> 8) : reg_val) & 0xFF;
+
+	return anx7625_reg_write(ctx, client, reg_addr, reg_data);
+}
+
 static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
 {
 	struct device *dev = ctx->dev;
@@ -506,34 +639,33 @@  static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
 	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
 				MIPI_LANE_CTRL_0, ctx->pdata.mipi_lanes - 1);
 
-	/* Htotal */
 	htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
-		ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
+			 ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
+	/* Htotal */
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_TOTAL_PIXELS_L, htotal, false);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_TOTAL_PIXELS_H, htotal, true);
 	/* Hactive */
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min, false);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min, true);
 	/* HFP */
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_FRONT_PORCH_H,
-			ctx->dt.hfront_porch.min >> 8);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min, false);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_FRONT_PORCH_H, ctx->dt.hfront_porch.min, true);
 	/* HWS */
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min, false);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min, true);
 	/* HBP */
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
-	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
-			HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min, false);
+	ret |= anx7625_timing_write(ctx, ctx->i2c.rx_p2_client,
+			HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min, true);
 	/* Vactive */
 	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
 			ctx->dt.vactive.min);
@@ -663,9 +795,15 @@  static int anx7625_dsi_config(struct anx7625_data *ctx)
 
 	DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
 
-	/* DSC disable */
-	ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
-				R_DSC_CTRL_0, ~DSC_EN);
+	ret = anx7625_set_dsc_params(ctx);
+	if (ctx->dsc_en)
+		/* DSC enable */
+		ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
+					R_DSC_CTRL_0, DSC_EN);
+	else
+		/* DSC disable */
+		ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
+					 R_DSC_CTRL_0, ~DSC_EN);
 
 	ret |= anx7625_api_dsi_config(ctx);
 
@@ -2083,6 +2221,7 @@  static int anx7625_setup_dsi_device(struct anx7625_data *ctx)
 		MIPI_DSI_MODE_VIDEO_HSE	|
 		MIPI_DSI_HS_PKT_END_ALIGNED;
 
+	dsi->dsc = &ctx->dsc;
 	ctx->dsi = dsi;
 
 	return 0;
@@ -2186,20 +2325,68 @@  anx7625_bridge_mode_valid(struct drm_bridge *bridge,
 	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
 	struct device *dev = ctx->dev;
 
-	DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
+	dev_dbg(dev, "drm mode checking\n");
+	if (mode->clock > SUPPORT_PIXEL_CLOCK)
+		return MODE_CLOCK_HIGH;
+
+	if (mode->clock < SUPPORT_MIN_PIXEL_CLOCK)
+		return MODE_CLOCK_LOW;
 
-	/* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
-	if (mode->clock > SUPPORT_PIXEL_CLOCK) {
-		DRM_DEV_DEBUG_DRIVER(dev,
-				     "drm mode invalid, pixelclock too high.\n");
+	if (mode->clock > DSC_PIXEL_CLOCK && (mode->hdisplay % 3 != 0))
 		return MODE_CLOCK_HIGH;
-	}
 
-	DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
+	dev_dbg(dev, "drm mode valid.\n");
 
 	return MODE_OK;
 }
 
+static void anx7625_dsc_enable(struct anx7625_data *ctx, bool en)
+{
+	int ret;
+	struct device *dev = ctx->dev;
+
+	ctx->dsc_en = en;
+
+	if (en) {
+		ctx->dsc.dsc_version_major = 1;
+		ctx->dsc.dsc_version_minor = 1;
+		ctx->dsc.slice_height = 8;
+		ctx->dsc.slice_width = ctx->dt.hactive.min / DSC_SLICE_NUM;
+		ctx->dsc.slice_count = DSC_SLICE_NUM;
+		ctx->dsc.bits_per_component = 8;
+		ctx->dsc.bits_per_pixel = 8 << 4; /* 4 fractional bits */
+		ctx->dsc.block_pred_enable = true;
+		ctx->dsc.native_420 = false;
+		ctx->dsc.native_422 = false;
+		ctx->dsc.simple_422 = false;
+		ctx->dsc.vbr_enable = false;
+		ctx->dsc.rc_model_size = DSC_RC_MODEL_SIZE_CONST;
+		ctx->dsc.pic_width = ctx->dt.hactive.min;
+		ctx->dsc.pic_height = ctx->dt.vactive.min;
+		ctx->dsc.convert_rgb = 1;
+		ctx->dsc.vbr_enable = 0;
+
+		drm_dsc_set_rc_buf_thresh(&ctx->dsc);
+		drm_dsc_set_const_params(&ctx->dsc);
+
+		ctx->dsc.initial_scale_value = drm_dsc_initial_scale_value(&ctx->dsc);
+		ctx->dsc.line_buf_depth = ctx->dsc.bits_per_component + 1;
+		ret = drm_dsc_setup_rc_params(&ctx->dsc, DRM_DSC_1_2_444);
+		if (ret < 0)
+			dev_warn(dev, "drm_dsc_setup_rc_params ret %d\n", ret);
+
+		drm_dsc_compute_rc_parameters(&ctx->dsc);
+
+		drm_dsc_pps_payload_pack((struct drm_dsc_picture_parameter_set *)&ctx->pps_table,
+					 &ctx->dsc);
+		dev_dbg(dev, "anx7625 enable dsc\n");
+	} else {
+		ctx->dsc.dsc_version_major = 0;
+		ctx->dsc.dsc_version_minor = 0;
+		dev_dbg(dev, "anx7625 disable dsc\n");
+	}
+}
+
 static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
 				    const struct drm_display_mode *old_mode,
 				    const struct drm_display_mode *mode)
@@ -2244,6 +2431,11 @@  static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
 	DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
 			     mode->vsync_end,
 			     mode->vtotal);
+
+	if (mode->clock > DSC_PIXEL_CLOCK)
+		anx7625_dsc_enable(ctx, true);
+	else
+		anx7625_dsc_enable(ctx, false);
 }
 
 static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
@@ -2258,26 +2450,33 @@  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
 
 	DRM_DEV_DEBUG_DRIVER(dev, "drm mode fixup set\n");
 
-	/* No need fixup for external monitor */
-	if (!ctx->pdata.panel_bridge)
-		return true;
-
 	hsync = mode->hsync_end - mode->hsync_start;
 	hfp = mode->hsync_start - mode->hdisplay;
 	hbp = mode->htotal - mode->hsync_end;
 	hblanking = mode->htotal - mode->hdisplay;
 
-	DRM_DEV_DEBUG_DRIVER(dev, "before mode fixup\n");
-	DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
-			     hsync, hfp, hbp, adj->clock);
-	DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
-			     adj->hsync_start, adj->hsync_end, adj->htotal);
-
+	dev_dbg(dev, "before mode fixup\n");
+	dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
+		hsync, hfp, hbp, adj->clock);
+	dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
+		adj->hsync_start, adj->hsync_end, adj->htotal);
 	adj_hfp = hfp;
 	adj_hsync = hsync;
 	adj_hbp = hbp;
 	adj_hblanking = hblanking;
 
+	if (mode->clock > DSC_PIXEL_CLOCK) {
+		adj_hsync = DSC_HSYNC_LEN;
+		adj_hfp = DSC_HFP_LEN;
+		adj_hbp = DSC_HBP_LEN;
+		vref = (u64)adj->clock * 1000 * 1000 / (adj->htotal * adj->vtotal);
+		goto calculate_timing;
+	}
+
+	/* No need fixup for external monitor */
+	if (!ctx->pdata.panel_bridge)
+		return true;
+
 	/* HFP needs to be even */
 	if (hfp & 0x1) {
 		adj_hfp += 1;
@@ -2349,16 +2548,21 @@  static bool anx7625_bridge_mode_fixup(struct drm_bridge *bridge,
 			adj_hfp -= delta_adj;
 	}
 
-	DRM_DEV_DEBUG_DRIVER(dev, "after mode fixup\n");
-	DRM_DEV_DEBUG_DRIVER(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
-			     adj_hsync, adj_hfp, adj_hbp, adj->clock);
+calculate_timing:
+
+	dev_dbg(dev, "after mode fixup\n");
+	dev_dbg(dev, "hsync(%d), hfp(%d), hbp(%d), clock(%d)\n",
+		adj_hsync, adj_hfp, adj_hbp, adj->clock);
 
 	/* Reconstruct timing */
 	adj->hsync_start = adj->hdisplay + adj_hfp;
 	adj->hsync_end = adj->hsync_start + adj_hsync;
 	adj->htotal = adj->hsync_end + adj_hbp;
-	DRM_DEV_DEBUG_DRIVER(dev, "hsync_start(%d), hsync_end(%d), htot(%d)\n",
-			     adj->hsync_start, adj->hsync_end, adj->htotal);
+	if (mode->clock > DSC_PIXEL_CLOCK)
+		adj->clock = (u64)vref * adj->htotal * adj->vtotal / 1000 / 1000;
+
+	dev_dbg(dev, "hsync_start(%d), hsync_end(%d), htot(%d), clock(%d)\n",
+		adj->hsync_start, adj->hsync_end, adj->htotal, adj->clock);
 
 	return true;
 }
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
index eb5580f1ab2f..db931f5800b1 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.h
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
@@ -149,6 +149,8 @@ 
 #define HFP_HBP_DEF		((HBLANKING_MIN - SYNC_LEN_DEF) / 2)
 #define VIDEO_CONTROL_0	0x08
 
+#define  TOTAL_LINES_L          0x12
+#define  TOTAL_LINES_H          0x13
 #define  ACTIVE_LINES_L         0x14
 #define  ACTIVE_LINES_H         0x15  /* Bit[7:6] are reserved */
 #define  VERTICAL_FRONT_PORCH   0x16
@@ -166,6 +168,32 @@ 
 #define  HORIZONTAL_BACK_PORCH_L      0x21
 #define  HORIZONTAL_BACK_PORCH_H      0x22  /* Bit[7:4] are reserved */
 
+#define  H_BLANK_L                    0x3E
+#define  H_BLANK_H                    0x3F
+#define  DSC_COMPRESS_RATIO           3
+#define  dsc_div(X)                   ((X) / DSC_COMPRESS_RATIO)
+#define  DSC_SLICE_NUM                2
+#define  DSC_PIXEL_CLOCK              250000
+#define  DSC_HSYNC_LEN                90
+#define  DSC_HFP_LEN                  177
+#define  DSC_HBP_LEN                  297
+
+#define  TOTAL_PIXEL_L_7E             0x50
+#define  TOTAL_PIXEL_H_7E             0x51  /* bit[7:6] are reserved */
+#define  ACTIVE_PIXEL_L_7E            0x52
+#define  ACTIVE_PIXEL_H_7E            0x53  /* bit[7:6] are reserved */
+#define  HORIZON_FRONT_PORCH_L_7E     0x54
+#define  HORIZON_FRONT_PORCH_H_7E     0x55
+#define  HORIZON_SYNC_WIDTH_L_7E      0x56
+#define  HORIZON_SYNC_WIDTH_H_7E      0x57
+#define  HORIZON_BACK_PORCH_L_7E      0x58
+#define  HORIZON_BACK_PORCH_H_7E      0x59
+
+#define  PPS_SIZE                     128
+#define  PPS_BLOCK_SIZE               32
+#define  R_PPS_REG_0                  0x80
+#define  R_I2C_1                      0x81
+
 /******** END of I2C Address 0x72 *********/
 
 /***************************************************************/
@@ -415,6 +443,7 @@  enum audio_wd_len {
 #define MAX_EDID_BLOCK	3
 #define EDID_TRY_CNT	3
 #define SUPPORT_PIXEL_CLOCK	300000
+#define SUPPORT_MIN_PIXEL_CLOCK	50000
 
 /***************** Display End *****************/
 
@@ -454,6 +483,7 @@  struct anx7625_data {
 	int hpd_high_cnt;
 	int dp_en;
 	int hdcp_cp;
+	bool dsc_en;
 	/* Lock for work queue */
 	struct mutex lock;
 	struct device *dev;
@@ -479,6 +509,8 @@  struct anx7625_data {
 	struct drm_connector *connector;
 	struct mipi_dsi_device *dsi;
 	struct drm_dp_aux aux;
+	struct drm_dsc_config dsc;
+	char pps_table[PPS_SIZE];
 };
 
 #endif  /* __ANX7625_H__ */