diff mbox series

[v5,1/1] drm/mediatek: dsi: fix scrolling of panel with small hfp or hbp

Message ID 20201013100625.13056-2-jitao.shi@mediatek.com (mailing list archive)
State New, archived
Headers show
Series fix scrolling of panel with small hfp or hbp | expand

Commit Message

Jitao Shi Oct. 13, 2020, 10:06 a.m. UTC
Replace horizontal_backporch_byte with vm->hback_porch * bpp to aovid
flowing judgement negative number.

if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
	data_phy_cycles * dsi->lanes + delta)

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 65 +++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 40 deletions(-)

Comments

Nicolas Boichat Oct. 13, 2020, 10:54 a.m. UTC | #1
On Tue, Oct 13, 2020 at 6:06 PM Jitao Shi <jitao.shi@mediatek.com> wrote:
>
> Replace horizontal_backporch_byte with vm->hback_porch * bpp to aovid
> flowing judgement negative number.
>
> if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
>         data_phy_cycles * dsi->lanes + delta)
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 65 +++++++++++++++-----------------------
>  1 file changed, 25 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 80b7a082e874..ddddf69ebeaf 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -445,6 +445,7 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
>         u32 horizontal_backporch_byte;
>         u32 horizontal_frontporch_byte;
>         u32 dsi_tmp_buf_bpp, data_phy_cycles;
> +       u32 delta;
>         struct mtk_phy_timing *timing = &dsi->phy_timing;
>
>         struct videomode *vm = &dsi->vm;
> @@ -466,50 +467,34 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
>         horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);
>
>         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> -               horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;
> +               horizontal_backporch_byte =
> +                       (vm->hback_porch * dsi_tmp_buf_bpp - 10);

These parentheses are not required, but it might be a little clearer to write:
(vm->hback_porch * dsi_tmp_buf_bpp) - 10;

>         else
> -               horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *
> -                                           dsi_tmp_buf_bpp;
> +               horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
> +                       dsi_tmp_buf_bpp - 10);

ditto:
((vm->hback_porch + vm->hsync_len) * dsi_tmp_buf_bpp) - 10;

But then, _maybe_ it's clearer to drop this hunk and just add this
below the if/else:

horizontal_backporch_byte -= 10;

>
>         data_phy_cycles = timing->lpx + timing->da_hs_prepare +
> -                         timing->da_hs_zero + timing->da_hs_exit;
> -
> -       if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
> -               if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> -                   data_phy_cycles * dsi->lanes + 18) {
> -                       horizontal_frontporch_byte =
> -                               vm->hfront_porch * dsi_tmp_buf_bpp -
> -                               (data_phy_cycles * dsi->lanes + 18) *
> -                               vm->hfront_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -
> -                       horizontal_backporch_byte =
> -                               horizontal_backporch_byte -
> -                               (data_phy_cycles * dsi->lanes + 18) *
> -                               vm->hback_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -               } else {
> -                       DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
> -                       horizontal_frontporch_byte = vm->hfront_porch *
> -                                                    dsi_tmp_buf_bpp;
> -               }
> +                         timing->da_hs_zero + timing->da_hs_exit + 3;

(for reference, apart from this `+ 3`, there is no functional change
in this hunk: this just moves delta outside of the if/else block,
which is a good idea for readability)

> +
> +       delta = (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ? 18 : 12;
> +
> +       if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
> +           data_phy_cycles * dsi->lanes + delta) {
> +               horizontal_frontporch_byte =
> +                       vm->hfront_porch * dsi_tmp_buf_bpp -
> +                       (data_phy_cycles * dsi->lanes + delta) *
> +                       vm->hfront_porch /
> +                       (vm->hfront_porch + vm->hback_porch);
> +
> +               horizontal_backporch_byte =
> +                       horizontal_backporch_byte -
> +                       (data_phy_cycles * dsi->lanes + delta) *
> +                       vm->hback_porch /
> +                       (vm->hfront_porch + vm->hback_porch);
>         } else {
> -               if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> -                   data_phy_cycles * dsi->lanes + 12) {
> -                       horizontal_frontporch_byte =
> -                               vm->hfront_porch * dsi_tmp_buf_bpp -
> -                               (data_phy_cycles * dsi->lanes + 12) *
> -                               vm->hfront_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -                       horizontal_backporch_byte = horizontal_backporch_byte -
> -                               (data_phy_cycles * dsi->lanes + 12) *
> -                               vm->hback_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -               } else {
> -                       DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
> -                       horizontal_frontporch_byte = vm->hfront_porch *
> -                                                    dsi_tmp_buf_bpp;
> -               }
> +               DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
> +               horizontal_frontporch_byte = vm->hfront_porch *
> +                                            dsi_tmp_buf_bpp;
>         }
>
>         writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
> --
> 2.12.5
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Chun-Kuang Hu Oct. 29, 2020, 1:22 p.m. UTC | #2
Hi, Jitao:

Jitao Shi <jitao.shi@mediatek.com> 於 2020年10月13日 週二 下午6:06寫道:
>
> Replace horizontal_backporch_byte with vm->hback_porch * bpp to aovid
> flowing judgement negative number.
>
> if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
>         data_phy_cycles * dsi->lanes + delta)
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 65 +++++++++++++++-----------------------
>  1 file changed, 25 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 80b7a082e874..ddddf69ebeaf 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -445,6 +445,7 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
>         u32 horizontal_backporch_byte;
>         u32 horizontal_frontporch_byte;
>         u32 dsi_tmp_buf_bpp, data_phy_cycles;
> +       u32 delta;
>         struct mtk_phy_timing *timing = &dsi->phy_timing;
>
>         struct videomode *vm = &dsi->vm;
> @@ -466,50 +467,34 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
>         horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);
>
>         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> -               horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;
> +               horizontal_backporch_byte =
> +                       (vm->hback_porch * dsi_tmp_buf_bpp - 10);
>         else
> -               horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *
> -                                           dsi_tmp_buf_bpp;
> +               horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
> +                       dsi_tmp_buf_bpp - 10);
>
>         data_phy_cycles = timing->lpx + timing->da_hs_prepare +
> -                         timing->da_hs_zero + timing->da_hs_exit;
> -
> -       if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
> -               if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> -                   data_phy_cycles * dsi->lanes + 18) {
> -                       horizontal_frontporch_byte =
> -                               vm->hfront_porch * dsi_tmp_buf_bpp -
> -                               (data_phy_cycles * dsi->lanes + 18) *
> -                               vm->hfront_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -
> -                       horizontal_backporch_byte =
> -                               horizontal_backporch_byte -
> -                               (data_phy_cycles * dsi->lanes + 18) *
> -                               vm->hback_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -               } else {
> -                       DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
> -                       horizontal_frontporch_byte = vm->hfront_porch *
> -                                                    dsi_tmp_buf_bpp;
> -               }
> +                         timing->da_hs_zero + timing->da_hs_exit + 3;
> +
> +       delta = (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ? 18 : 12;
> +
> +       if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
> +           data_phy_cycles * dsi->lanes + delta) {
> +               horizontal_frontporch_byte =
> +                       vm->hfront_porch * dsi_tmp_buf_bpp -
> +                       (data_phy_cycles * dsi->lanes + delta) *
> +                       vm->hfront_porch /
> +                       (vm->hfront_porch + vm->hback_porch);
> +
> +               horizontal_backporch_byte =
> +                       horizontal_backporch_byte -
> +                       (data_phy_cycles * dsi->lanes + delta) *
> +                       vm->hback_porch /
> +                       (vm->hfront_porch + vm->hback_porch);
>         } else {
> -               if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
> -                   data_phy_cycles * dsi->lanes + 12) {
> -                       horizontal_frontporch_byte =
> -                               vm->hfront_porch * dsi_tmp_buf_bpp -
> -                               (data_phy_cycles * dsi->lanes + 12) *
> -                               vm->hfront_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -                       horizontal_backporch_byte = horizontal_backporch_byte -
> -                               (data_phy_cycles * dsi->lanes + 12) *
> -                               vm->hback_porch /
> -                               (vm->hfront_porch + vm->hback_porch);
> -               } else {
> -                       DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
> -                       horizontal_frontporch_byte = vm->hfront_porch *
> -                                                    dsi_tmp_buf_bpp;
> -               }
> +               DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
> +               horizontal_frontporch_byte = vm->hfront_porch *
> +                                            dsi_tmp_buf_bpp;

I've applied this patch, but small hbp has problem because
horizontal_backporch_byte < 0.
I try to modify this patch according to two assumption:

1. horizontal_backporch_byte should be smaller than (vm->hback_porch +
vm->hsync_len) * dsi_tmp_buf_bpp at least 10.
2. horizontal_backporch_byte should >= 0.

According to these two assumption, I've a patch [1]. My key point is
that I use horizontal_backporch_byte to calculate the ratio to
subtract it. Is my assumption correct?
If not, please explain why do you calculate in this way, so we could
find out how to solve this problem.

[1] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2506992

Regards,
Chun-Kuang.

>         }
>
>         writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
> --
> 2.12.5
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 80b7a082e874..ddddf69ebeaf 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -445,6 +445,7 @@  static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
 	u32 horizontal_backporch_byte;
 	u32 horizontal_frontporch_byte;
 	u32 dsi_tmp_buf_bpp, data_phy_cycles;
+	u32 delta;
 	struct mtk_phy_timing *timing = &dsi->phy_timing;
 
 	struct videomode *vm = &dsi->vm;
@@ -466,50 +467,34 @@  static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
 	horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);
 
 	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
-		horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;
+		horizontal_backporch_byte =
+			(vm->hback_porch * dsi_tmp_buf_bpp - 10);
 	else
-		horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *
-					    dsi_tmp_buf_bpp;
+		horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
+			dsi_tmp_buf_bpp - 10);
 
 	data_phy_cycles = timing->lpx + timing->da_hs_prepare +
-			  timing->da_hs_zero + timing->da_hs_exit;
-
-	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
-		if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
-		    data_phy_cycles * dsi->lanes + 18) {
-			horizontal_frontporch_byte =
-				vm->hfront_porch * dsi_tmp_buf_bpp -
-				(data_phy_cycles * dsi->lanes + 18) *
-				vm->hfront_porch /
-				(vm->hfront_porch + vm->hback_porch);
-
-			horizontal_backporch_byte =
-				horizontal_backporch_byte -
-				(data_phy_cycles * dsi->lanes + 18) *
-				vm->hback_porch /
-				(vm->hfront_porch + vm->hback_porch);
-		} else {
-			DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
-			horizontal_frontporch_byte = vm->hfront_porch *
-						     dsi_tmp_buf_bpp;
-		}
+			  timing->da_hs_zero + timing->da_hs_exit + 3;
+
+	delta = (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ? 18 : 12;
+
+	if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
+	    data_phy_cycles * dsi->lanes + delta) {
+		horizontal_frontporch_byte =
+			vm->hfront_porch * dsi_tmp_buf_bpp -
+			(data_phy_cycles * dsi->lanes + delta) *
+			vm->hfront_porch /
+			(vm->hfront_porch + vm->hback_porch);
+
+		horizontal_backporch_byte =
+			horizontal_backporch_byte -
+			(data_phy_cycles * dsi->lanes + delta) *
+			vm->hback_porch /
+			(vm->hfront_porch + vm->hback_porch);
 	} else {
-		if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
-		    data_phy_cycles * dsi->lanes + 12) {
-			horizontal_frontporch_byte =
-				vm->hfront_porch * dsi_tmp_buf_bpp -
-				(data_phy_cycles * dsi->lanes + 12) *
-				vm->hfront_porch /
-				(vm->hfront_porch + vm->hback_porch);
-			horizontal_backporch_byte = horizontal_backporch_byte -
-				(data_phy_cycles * dsi->lanes + 12) *
-				vm->hback_porch /
-				(vm->hfront_porch + vm->hback_porch);
-		} else {
-			DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
-			horizontal_frontporch_byte = vm->hfront_porch *
-						     dsi_tmp_buf_bpp;
-		}
+		DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
+		horizontal_frontporch_byte = vm->hfront_porch *
+					     dsi_tmp_buf_bpp;
 	}
 
 	writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);