diff mbox series

[v5,12/29] drm/omap: dsi: untangle vc & channel

Message ID 20201208122855.254819-13-tomi.valkeinen@ti.com (mailing list archive)
State New
Headers show
Series Convert DSI code to use drm_mipi_dsi and drm_panel (second half) | expand

Commit Message

Tomi Valkeinen Dec. 8, 2020, 12:28 p.m. UTC
DSI virtual channel and hardware VC blocks have gotten tangled as
described in the previous commits. This has not caused any issues, as
the value for both is 0, so it happens to work.

To fix the issue, change the code to use the correct one of the two.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
---
 drivers/gpu/drm/omapdrm/dss/dsi.c | 43 +++++++++++++++----------------
 1 file changed, 21 insertions(+), 22 deletions(-)

Comments

Laurent Pinchart Dec. 8, 2020, 3:41 p.m. UTC | #1
Hi Tomi,

Thank you for the patch.

On Tue, Dec 08, 2020 at 02:28:38PM +0200, Tomi Valkeinen wrote:
> DSI virtual channel and hardware VC blocks have gotten tangled as
> described in the previous commits. This has not caused any issues, as
> the value for both is 0, so it happens to work.
> 
> To fix the issue, change the code to use the correct one of the two.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
>  drivers/gpu/drm/omapdrm/dss/dsi.c | 43 +++++++++++++++----------------
>  1 file changed, 21 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index 8d8412199693..a1f3623f45b1 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -2613,7 +2613,7 @@ static inline void dsi_vc_write_long_header(struct dsi_data *dsi, int vc,
>  
>  	WARN_ON(!dsi_bus_is_locked(dsi));
>  
> -	data_id = data_type | vc << 6;
> +	data_id = data_type | channel << 6;
>  
>  	val = FLD_VAL(data_id, 7, 0) | FLD_VAL(len, 23, 8) |
>  		FLD_VAL(ecc, 31, 24);
> @@ -2647,12 +2647,12 @@ static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
>  		DSSDBG("dsi_vc_send_long, %d bytes\n", msg->tx_len);
>  
>  	/* len + header */
> -	if (dsi->vc[msg->channel].tx_fifo_size * 32 * 4 < msg->tx_len + 4) {
> +	if (dsi->vc[vc].tx_fifo_size * 32 * 4 < msg->tx_len + 4) {
>  		DSSERR("unable to send long packet: packet too long.\n");
>  		return -EINVAL;
>  	}
>  
> -	dsi_vc_config_source(dsi, msg->channel, DSI_VC_SOURCE_L4);
> +	dsi_vc_config_source(dsi, vc, DSI_VC_SOURCE_L4);
>  
>  	dsi_vc_write_long_header(dsi, vc, msg->channel, msg->type, msg->tx_len, 0);
>  
> @@ -2666,7 +2666,7 @@ static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
>  		b3 = *p++;
>  		b4 = *p++;
>  
> -		dsi_vc_write_long_payload(dsi, msg->channel, b1, b2, b3, b4);
> +		dsi_vc_write_long_payload(dsi, vc, b1, b2, b3, b4);
>  	}
>  
>  	i = msg->tx_len % 4;
> @@ -2691,7 +2691,7 @@ static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
>  			break;
>  		}
>  
> -		dsi_vc_write_long_payload(dsi, msg->channel, b1, b2, b3, 0);
> +		dsi_vc_write_long_payload(dsi, vc, b1, b2, b3, 0);
>  	}
>  
>  	return r;
> @@ -2711,11 +2711,11 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
>  
>  	if (dsi->debug_write)
>  		DSSDBG("dsi_vc_send_short(ch%d, dt %#x, b1 %#x, b2 %#x)\n",
> -		       msg->channel, msg->type, pkt.header[1], pkt.header[2]);
> +		       vc, msg->type, pkt.header[1], pkt.header[2]);
>  
> -	dsi_vc_config_source(dsi, msg->channel, DSI_VC_SOURCE_L4);
> +	dsi_vc_config_source(dsi, vc, DSI_VC_SOURCE_L4);
>  
> -	if (FLD_GET(dsi_read_reg(dsi, DSI_VC_CTRL(msg->channel)), 16, 16)) {
> +	if (FLD_GET(dsi_read_reg(dsi, DSI_VC_CTRL(vc)), 16, 16)) {
>  		DSSERR("ERROR FIFO FULL, aborting transfer\n");
>  		return -EINVAL;
>  	}
> @@ -2723,7 +2723,7 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
>  	r = pkt.header[3] << 24 | pkt.header[2] << 16 | pkt.header[1] << 8 |
>  	    pkt.header[0];
>  
> -	dsi_write_reg(dsi, DSI_VC_SHORT_PACKET_HEADER(msg->channel), r);
> +	dsi_write_reg(dsi, DSI_VC_SHORT_PACKET_HEADER(vc), r);
>  
>  	return 0;
>  }
> @@ -2731,7 +2731,7 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
>  static int dsi_vc_send_null(struct dsi_data *dsi, int vc, int channel)
>  {
>  	const struct mipi_dsi_msg msg = {
> -		.channel = vc,
> +		.channel = channel,
>  		.type = MIPI_DSI_NULL_PACKET,
>  	};
>  
> @@ -2759,16 +2759,16 @@ static int dsi_vc_write_common(struct omap_dss_device *dssdev, int vc,
>  	 * In that case we can return early.
>  	 */
>  
> -	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
> +	r = dsi_vc_send_bta_sync(dssdev, vc);
>  	if (r) {
>  		DSSERR("bta sync failed\n");
>  		return r;
>  	}
>  
>  	/* RX_FIFO_NOT_EMPTY */
> -	if (REG_GET(dsi, DSI_VC_CTRL(msg->channel), 20, 20)) {
> +	if (REG_GET(dsi, DSI_VC_CTRL(vc), 20, 20)) {
>  		DSSERR("rx fifo not empty after write, dumping data:\n");
> -		dsi_vc_flush_receive_data(dsi, msg->channel);
> +		dsi_vc_flush_receive_data(dsi, vc);
>  		return -EIO;
>  	}
>  
> @@ -2888,21 +2888,20 @@ static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int vc,
>  {
>  	struct dsi_data *dsi = to_dsi_data(dssdev);
>  	u8 cmd = ((u8 *)msg->tx_buf)[0];
> -	u8 channel = msg->channel;
>  	int r;
>  
>  	if (dsi->debug_read)
> -		DSSDBG("%s(ch %d, cmd %x)\n", __func__, channel, cmd);
> +		DSSDBG("%s(ch %d, cmd %x)\n", __func__, vc, cmd);

How about also renaming ch to vc in the message ?

>  
>  	r = dsi_vc_send_short(dsi, vc, msg);
>  	if (r)
>  		goto err;
>  
> -	r = dsi_vc_send_bta_sync(dssdev, channel);
> +	r = dsi_vc_send_bta_sync(dssdev, vc);
>  	if (r)
>  		goto err;
>  
> -	r = dsi_vc_read_rx_fifo(dsi, channel, msg->rx_buf, msg->rx_len,
> +	r = dsi_vc_read_rx_fifo(dsi, vc, msg->rx_buf, msg->rx_len,
>  		DSS_DSI_CONTENT_DCS);
>  	if (r < 0)
>  		goto err;
> @@ -2914,7 +2913,7 @@ static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int vc,
>  
>  	return 0;
>  err:
> -	DSSERR("%s(ch %d, cmd 0x%02x) failed\n", __func__,  msg->channel, cmd);
> +	DSSERR("%s(ch %d, cmd 0x%02x) failed\n", __func__,  vc, cmd);

Same here.

>  	return r;
>  }
>  
> @@ -2928,11 +2927,11 @@ static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int vc,
>  	if (r)
>  		goto err;
>  
> -	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
> +	r = dsi_vc_send_bta_sync(dssdev, vc);
>  	if (r)
>  		goto err;
>  
> -	r = dsi_vc_read_rx_fifo(dsi, msg->channel, msg->rx_buf, msg->rx_len,
> +	r = dsi_vc_read_rx_fifo(dsi, vc, msg->rx_buf, msg->rx_len,
>  		DSS_DSI_CONTENT_GENERIC);
>  	if (r < 0)
>  		goto err;
> @@ -2944,7 +2943,7 @@ static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int vc,
>  
>  	return 0;
>  err:
> -	DSSERR("%s(ch %d, reqlen %d) failed\n", __func__,  msg->channel, msg->tx_len);
> +	DSSERR("%s(ch %d, reqlen %d) failed\n", __func__,  vc, msg->tx_len);

And here.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>  	return r;
>  }
>  
> @@ -4893,7 +4892,7 @@ static ssize_t _omap_dsi_host_transfer(struct dsi_data *dsi, int vc,
>  	int r;
>  
>  	if (!!(msg->flags & MIPI_DSI_MSG_USE_LPM) != dsi->in_lp_mode)
> -		dsi_vc_enable_hs(dssdev, msg->channel,
> +		dsi_vc_enable_hs(dssdev, vc,
>  				 !(msg->flags & MIPI_DSI_MSG_USE_LPM));
>  
>  	switch (msg->type) {
Sebastian Reichel Dec. 14, 2020, 3:47 p.m. UTC | #2
On Tue, Dec 08, 2020 at 05:41:23PM +0200, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Tue, Dec 08, 2020 at 02:28:38PM +0200, Tomi Valkeinen wrote:
> > DSI virtual channel and hardware VC blocks have gotten tangled as
> > described in the previous commits. This has not caused any issues, as
> > the value for both is 0, so it happens to work.
> > 
> > To fix the issue, change the code to use the correct one of the two.
> > 
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > ---
> >  drivers/gpu/drm/omapdrm/dss/dsi.c | 43 +++++++++++++++----------------
> >  1 file changed, 21 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> > index 8d8412199693..a1f3623f45b1 100644
> > --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> > +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> > @@ -2613,7 +2613,7 @@ static inline void dsi_vc_write_long_header(struct dsi_data *dsi, int vc,
> >  
> >  	WARN_ON(!dsi_bus_is_locked(dsi));
> >  
> > -	data_id = data_type | vc << 6;
> > +	data_id = data_type | channel << 6;
> >  
> >  	val = FLD_VAL(data_id, 7, 0) | FLD_VAL(len, 23, 8) |
> >  		FLD_VAL(ecc, 31, 24);
> > @@ -2647,12 +2647,12 @@ static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
> >  		DSSDBG("dsi_vc_send_long, %d bytes\n", msg->tx_len);
> >  
> >  	/* len + header */
> > -	if (dsi->vc[msg->channel].tx_fifo_size * 32 * 4 < msg->tx_len + 4) {
> > +	if (dsi->vc[vc].tx_fifo_size * 32 * 4 < msg->tx_len + 4) {
> >  		DSSERR("unable to send long packet: packet too long.\n");
> >  		return -EINVAL;
> >  	}
> >  
> > -	dsi_vc_config_source(dsi, msg->channel, DSI_VC_SOURCE_L4);
> > +	dsi_vc_config_source(dsi, vc, DSI_VC_SOURCE_L4);
> >  
> >  	dsi_vc_write_long_header(dsi, vc, msg->channel, msg->type, msg->tx_len, 0);
> >  
> > @@ -2666,7 +2666,7 @@ static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
> >  		b3 = *p++;
> >  		b4 = *p++;
> >  
> > -		dsi_vc_write_long_payload(dsi, msg->channel, b1, b2, b3, b4);
> > +		dsi_vc_write_long_payload(dsi, vc, b1, b2, b3, b4);
> >  	}
> >  
> >  	i = msg->tx_len % 4;
> > @@ -2691,7 +2691,7 @@ static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
> >  			break;
> >  		}
> >  
> > -		dsi_vc_write_long_payload(dsi, msg->channel, b1, b2, b3, 0);
> > +		dsi_vc_write_long_payload(dsi, vc, b1, b2, b3, 0);
> >  	}
> >  
> >  	return r;
> > @@ -2711,11 +2711,11 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
> >  
> >  	if (dsi->debug_write)
> >  		DSSDBG("dsi_vc_send_short(ch%d, dt %#x, b1 %#x, b2 %#x)\n",
> > -		       msg->channel, msg->type, pkt.header[1], pkt.header[2]);
> > +		       vc, msg->type, pkt.header[1], pkt.header[2]);

There is another "ch%d" filled with vc. With this and Laurent
findings fixed:

Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>

-- Sebastian

> >  
> > -	dsi_vc_config_source(dsi, msg->channel, DSI_VC_SOURCE_L4);
> > +	dsi_vc_config_source(dsi, vc, DSI_VC_SOURCE_L4);
> >  
> > -	if (FLD_GET(dsi_read_reg(dsi, DSI_VC_CTRL(msg->channel)), 16, 16)) {
> > +	if (FLD_GET(dsi_read_reg(dsi, DSI_VC_CTRL(vc)), 16, 16)) {
> >  		DSSERR("ERROR FIFO FULL, aborting transfer\n");
> >  		return -EINVAL;
> >  	}
> > @@ -2723,7 +2723,7 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
> >  	r = pkt.header[3] << 24 | pkt.header[2] << 16 | pkt.header[1] << 8 |
> >  	    pkt.header[0];
> >  
> > -	dsi_write_reg(dsi, DSI_VC_SHORT_PACKET_HEADER(msg->channel), r);
> > +	dsi_write_reg(dsi, DSI_VC_SHORT_PACKET_HEADER(vc), r);
> >  
> >  	return 0;
> >  }
> > @@ -2731,7 +2731,7 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
> >  static int dsi_vc_send_null(struct dsi_data *dsi, int vc, int channel)
> >  {
> >  	const struct mipi_dsi_msg msg = {
> > -		.channel = vc,
> > +		.channel = channel,
> >  		.type = MIPI_DSI_NULL_PACKET,
> >  	};
> >  
> > @@ -2759,16 +2759,16 @@ static int dsi_vc_write_common(struct omap_dss_device *dssdev, int vc,
> >  	 * In that case we can return early.
> >  	 */
> >  
> > -	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
> > +	r = dsi_vc_send_bta_sync(dssdev, vc);
> >  	if (r) {
> >  		DSSERR("bta sync failed\n");
> >  		return r;
> >  	}
> >  
> >  	/* RX_FIFO_NOT_EMPTY */
> > -	if (REG_GET(dsi, DSI_VC_CTRL(msg->channel), 20, 20)) {
> > +	if (REG_GET(dsi, DSI_VC_CTRL(vc), 20, 20)) {
> >  		DSSERR("rx fifo not empty after write, dumping data:\n");
> > -		dsi_vc_flush_receive_data(dsi, msg->channel);
> > +		dsi_vc_flush_receive_data(dsi, vc);
> >  		return -EIO;
> >  	}
> >  
> > @@ -2888,21 +2888,20 @@ static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int vc,
> >  {
> >  	struct dsi_data *dsi = to_dsi_data(dssdev);
> >  	u8 cmd = ((u8 *)msg->tx_buf)[0];
> > -	u8 channel = msg->channel;
> >  	int r;
> >  
> >  	if (dsi->debug_read)
> > -		DSSDBG("%s(ch %d, cmd %x)\n", __func__, channel, cmd);
> > +		DSSDBG("%s(ch %d, cmd %x)\n", __func__, vc, cmd);
> 
> How about also renaming ch to vc in the message ?
> 
> >  
> >  	r = dsi_vc_send_short(dsi, vc, msg);
> >  	if (r)
> >  		goto err;
> >  
> > -	r = dsi_vc_send_bta_sync(dssdev, channel);
> > +	r = dsi_vc_send_bta_sync(dssdev, vc);
> >  	if (r)
> >  		goto err;
> >  
> > -	r = dsi_vc_read_rx_fifo(dsi, channel, msg->rx_buf, msg->rx_len,
> > +	r = dsi_vc_read_rx_fifo(dsi, vc, msg->rx_buf, msg->rx_len,
> >  		DSS_DSI_CONTENT_DCS);
> >  	if (r < 0)
> >  		goto err;
> > @@ -2914,7 +2913,7 @@ static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int vc,
> >  
> >  	return 0;
> >  err:
> > -	DSSERR("%s(ch %d, cmd 0x%02x) failed\n", __func__,  msg->channel, cmd);
> > +	DSSERR("%s(ch %d, cmd 0x%02x) failed\n", __func__,  vc, cmd);
> 
> Same here.
> 
> >  	return r;
> >  }
> >  
> > @@ -2928,11 +2927,11 @@ static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int vc,
> >  	if (r)
> >  		goto err;
> >  
> > -	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
> > +	r = dsi_vc_send_bta_sync(dssdev, vc);
> >  	if (r)
> >  		goto err;
> >  
> > -	r = dsi_vc_read_rx_fifo(dsi, msg->channel, msg->rx_buf, msg->rx_len,
> > +	r = dsi_vc_read_rx_fifo(dsi, vc, msg->rx_buf, msg->rx_len,
> >  		DSS_DSI_CONTENT_GENERIC);
> >  	if (r < 0)
> >  		goto err;
> > @@ -2944,7 +2943,7 @@ static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int vc,
> >  
> >  	return 0;
> >  err:
> > -	DSSERR("%s(ch %d, reqlen %d) failed\n", __func__,  msg->channel, msg->tx_len);
> > +	DSSERR("%s(ch %d, reqlen %d) failed\n", __func__,  vc, msg->tx_len);
> 
> And here.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> >  	return r;
> >  }
> >  
> > @@ -4893,7 +4892,7 @@ static ssize_t _omap_dsi_host_transfer(struct dsi_data *dsi, int vc,
> >  	int r;
> >  
> >  	if (!!(msg->flags & MIPI_DSI_MSG_USE_LPM) != dsi->in_lp_mode)
> > -		dsi_vc_enable_hs(dssdev, msg->channel,
> > +		dsi_vc_enable_hs(dssdev, vc,
> >  				 !(msg->flags & MIPI_DSI_MSG_USE_LPM));
> >  
> >  	switch (msg->type) {
> 
> -- 
> Regards,
> 
> Laurent Pinchart
diff mbox series

Patch

diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
index 8d8412199693..a1f3623f45b1 100644
--- a/drivers/gpu/drm/omapdrm/dss/dsi.c
+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
@@ -2613,7 +2613,7 @@  static inline void dsi_vc_write_long_header(struct dsi_data *dsi, int vc,
 
 	WARN_ON(!dsi_bus_is_locked(dsi));
 
-	data_id = data_type | vc << 6;
+	data_id = data_type | channel << 6;
 
 	val = FLD_VAL(data_id, 7, 0) | FLD_VAL(len, 23, 8) |
 		FLD_VAL(ecc, 31, 24);
@@ -2647,12 +2647,12 @@  static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
 		DSSDBG("dsi_vc_send_long, %d bytes\n", msg->tx_len);
 
 	/* len + header */
-	if (dsi->vc[msg->channel].tx_fifo_size * 32 * 4 < msg->tx_len + 4) {
+	if (dsi->vc[vc].tx_fifo_size * 32 * 4 < msg->tx_len + 4) {
 		DSSERR("unable to send long packet: packet too long.\n");
 		return -EINVAL;
 	}
 
-	dsi_vc_config_source(dsi, msg->channel, DSI_VC_SOURCE_L4);
+	dsi_vc_config_source(dsi, vc, DSI_VC_SOURCE_L4);
 
 	dsi_vc_write_long_header(dsi, vc, msg->channel, msg->type, msg->tx_len, 0);
 
@@ -2666,7 +2666,7 @@  static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
 		b3 = *p++;
 		b4 = *p++;
 
-		dsi_vc_write_long_payload(dsi, msg->channel, b1, b2, b3, b4);
+		dsi_vc_write_long_payload(dsi, vc, b1, b2, b3, b4);
 	}
 
 	i = msg->tx_len % 4;
@@ -2691,7 +2691,7 @@  static int dsi_vc_send_long(struct dsi_data *dsi, int vc,
 			break;
 		}
 
-		dsi_vc_write_long_payload(dsi, msg->channel, b1, b2, b3, 0);
+		dsi_vc_write_long_payload(dsi, vc, b1, b2, b3, 0);
 	}
 
 	return r;
@@ -2711,11 +2711,11 @@  static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
 
 	if (dsi->debug_write)
 		DSSDBG("dsi_vc_send_short(ch%d, dt %#x, b1 %#x, b2 %#x)\n",
-		       msg->channel, msg->type, pkt.header[1], pkt.header[2]);
+		       vc, msg->type, pkt.header[1], pkt.header[2]);
 
-	dsi_vc_config_source(dsi, msg->channel, DSI_VC_SOURCE_L4);
+	dsi_vc_config_source(dsi, vc, DSI_VC_SOURCE_L4);
 
-	if (FLD_GET(dsi_read_reg(dsi, DSI_VC_CTRL(msg->channel)), 16, 16)) {
+	if (FLD_GET(dsi_read_reg(dsi, DSI_VC_CTRL(vc)), 16, 16)) {
 		DSSERR("ERROR FIFO FULL, aborting transfer\n");
 		return -EINVAL;
 	}
@@ -2723,7 +2723,7 @@  static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
 	r = pkt.header[3] << 24 | pkt.header[2] << 16 | pkt.header[1] << 8 |
 	    pkt.header[0];
 
-	dsi_write_reg(dsi, DSI_VC_SHORT_PACKET_HEADER(msg->channel), r);
+	dsi_write_reg(dsi, DSI_VC_SHORT_PACKET_HEADER(vc), r);
 
 	return 0;
 }
@@ -2731,7 +2731,7 @@  static int dsi_vc_send_short(struct dsi_data *dsi, int vc,
 static int dsi_vc_send_null(struct dsi_data *dsi, int vc, int channel)
 {
 	const struct mipi_dsi_msg msg = {
-		.channel = vc,
+		.channel = channel,
 		.type = MIPI_DSI_NULL_PACKET,
 	};
 
@@ -2759,16 +2759,16 @@  static int dsi_vc_write_common(struct omap_dss_device *dssdev, int vc,
 	 * In that case we can return early.
 	 */
 
-	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
+	r = dsi_vc_send_bta_sync(dssdev, vc);
 	if (r) {
 		DSSERR("bta sync failed\n");
 		return r;
 	}
 
 	/* RX_FIFO_NOT_EMPTY */
-	if (REG_GET(dsi, DSI_VC_CTRL(msg->channel), 20, 20)) {
+	if (REG_GET(dsi, DSI_VC_CTRL(vc), 20, 20)) {
 		DSSERR("rx fifo not empty after write, dumping data:\n");
-		dsi_vc_flush_receive_data(dsi, msg->channel);
+		dsi_vc_flush_receive_data(dsi, vc);
 		return -EIO;
 	}
 
@@ -2888,21 +2888,20 @@  static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int vc,
 {
 	struct dsi_data *dsi = to_dsi_data(dssdev);
 	u8 cmd = ((u8 *)msg->tx_buf)[0];
-	u8 channel = msg->channel;
 	int r;
 
 	if (dsi->debug_read)
-		DSSDBG("%s(ch %d, cmd %x)\n", __func__, channel, cmd);
+		DSSDBG("%s(ch %d, cmd %x)\n", __func__, vc, cmd);
 
 	r = dsi_vc_send_short(dsi, vc, msg);
 	if (r)
 		goto err;
 
-	r = dsi_vc_send_bta_sync(dssdev, channel);
+	r = dsi_vc_send_bta_sync(dssdev, vc);
 	if (r)
 		goto err;
 
-	r = dsi_vc_read_rx_fifo(dsi, channel, msg->rx_buf, msg->rx_len,
+	r = dsi_vc_read_rx_fifo(dsi, vc, msg->rx_buf, msg->rx_len,
 		DSS_DSI_CONTENT_DCS);
 	if (r < 0)
 		goto err;
@@ -2914,7 +2913,7 @@  static int dsi_vc_dcs_read(struct omap_dss_device *dssdev, int vc,
 
 	return 0;
 err:
-	DSSERR("%s(ch %d, cmd 0x%02x) failed\n", __func__,  msg->channel, cmd);
+	DSSERR("%s(ch %d, cmd 0x%02x) failed\n", __func__,  vc, cmd);
 	return r;
 }
 
@@ -2928,11 +2927,11 @@  static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int vc,
 	if (r)
 		goto err;
 
-	r = dsi_vc_send_bta_sync(dssdev, msg->channel);
+	r = dsi_vc_send_bta_sync(dssdev, vc);
 	if (r)
 		goto err;
 
-	r = dsi_vc_read_rx_fifo(dsi, msg->channel, msg->rx_buf, msg->rx_len,
+	r = dsi_vc_read_rx_fifo(dsi, vc, msg->rx_buf, msg->rx_len,
 		DSS_DSI_CONTENT_GENERIC);
 	if (r < 0)
 		goto err;
@@ -2944,7 +2943,7 @@  static int dsi_vc_generic_read(struct omap_dss_device *dssdev, int vc,
 
 	return 0;
 err:
-	DSSERR("%s(ch %d, reqlen %d) failed\n", __func__,  msg->channel, msg->tx_len);
+	DSSERR("%s(ch %d, reqlen %d) failed\n", __func__,  vc, msg->tx_len);
 	return r;
 }
 
@@ -4893,7 +4892,7 @@  static ssize_t _omap_dsi_host_transfer(struct dsi_data *dsi, int vc,
 	int r;
 
 	if (!!(msg->flags & MIPI_DSI_MSG_USE_LPM) != dsi->in_lp_mode)
-		dsi_vc_enable_hs(dssdev, msg->channel,
+		dsi_vc_enable_hs(dssdev, vc,
 				 !(msg->flags & MIPI_DSI_MSG_USE_LPM));
 
 	switch (msg->type) {