diff mbox series

[v14,5/9] drm/bridge: dw-hdmi: repair interworking with hdmi-connector for jz4780

Message ID 8703a3e48574c09e8756b79e8f69be7d84926fe9.1644675566.git.hns@goldelico.com (mailing list archive)
State New, archived
Headers show
Series MIPS: JZ4780 and CI20 HDMI | expand

Commit Message

H. Nikolaus Schaller Feb. 12, 2022, 2:19 p.m. UTC
Commit 7cd70656d1285b ("drm/bridge: display-connector: implement bus fmts callbacks")

introduced a new mechanism to negotiate bus formats between hdmi connector
and the synopsys hdmi driver inside the jz4780.

By this, the dw-hdmi is no longer the only bridge and sets up a list
of formats in dw_hdmi_bridge_atomic_get_output_bus_fmts().

This includes MEDIA_BUS_FMT_UYVY8_1X16 which is chosen for the jz4780 but only
produces a black screen.

This fix is based on the observation that max_bpc = 0 when running this
function while info->bpc = 8. Since the formats checks before this always test
for max_bpc >= info->pbc indirectly my assumption is that we must check it
here as well.

Adding the proposed patch makes the CI20/jz4780 panel work again in
MEDIA_BUS_FMT_RGB888_1X24 mode.

Fixes: 7cd70656d1285b ("drm/bridge: display-connector: implement bus fmts callbacks")
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Paul Cercueil Feb. 12, 2022, 3:06 p.m. UTC | #1
Hi Nikolaus,


Le sam., févr. 12 2022 at 15:19:23 +0100, H. Nikolaus Schaller 
<hns@goldelico.com> a écrit :
> Commit 7cd70656d1285b ("drm/bridge: display-connector: implement bus 
> fmts callbacks")
> 
> introduced a new mechanism to negotiate bus formats between hdmi 
> connector
> and the synopsys hdmi driver inside the jz4780.
> 
> By this, the dw-hdmi is no longer the only bridge and sets up a list
> of formats in dw_hdmi_bridge_atomic_get_output_bus_fmts().
> 
> This includes MEDIA_BUS_FMT_UYVY8_1X16 which is chosen for the jz4780 
> but only
> produces a black screen.

Neil pushed a fix yesterday that looks like it could fix your issue.
The fix is: 1528038385c0 ("drm/bridge: dw-hdmi: use safe format when 
first in bridge chain")

Could you try if it does indeed fix your issue?

Cheers,
-Paul

> This fix is based on the observation that max_bpc = 0 when running 
> this
> function while info->bpc = 8. Since the formats checks before this 
> always test
> for max_bpc >= info->pbc indirectly my assumption is that we must 
> check it
> here as well.
> 
> Adding the proposed patch makes the CI20/jz4780 panel work again in
> MEDIA_BUS_FMT_RGB888_1X24 mode.
> 
> Fixes: 7cd70656d1285b ("drm/bridge: display-connector: implement bus 
> fmts callbacks")
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c 
> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index b0d8110dd412c..826a055a7a273 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2620,10 +2620,10 @@ static u32 
> *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
>  		output_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
>  	}
> 
> -	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR422)
> +	if (max_bpc >= info->bpc && info->color_formats & 
> DRM_COLOR_FORMAT_YCBCR422)
>  		output_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
> 
> -	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR444)
> +	if (max_bpc >= info->bpc && info->color_formats & 
> DRM_COLOR_FORMAT_YCBCR444)
>  		output_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
> 
>  	/* Default 8bit RGB fallback */
> --
> 2.33.0
>
H. Nikolaus Schaller Feb. 12, 2022, 3:50 p.m. UTC | #2
> Am 12.02.2022 um 16:06 schrieb Paul Cercueil <paul@crapouillou.net>:
> 
> Hi Nikolaus,
> 
> 
> Le sam., févr. 12 2022 at 15:19:23 +0100, H. Nikolaus Schaller <hns@goldelico.com> a écrit :
>> Commit 7cd70656d1285b ("drm/bridge: display-connector: implement bus fmts callbacks")
>> introduced a new mechanism to negotiate bus formats between hdmi connector
>> and the synopsys hdmi driver inside the jz4780.
>> By this, the dw-hdmi is no longer the only bridge and sets up a list
>> of formats in dw_hdmi_bridge_atomic_get_output_bus_fmts().
>> This includes MEDIA_BUS_FMT_UYVY8_1X16 which is chosen for the jz4780 but only
>> produces a black screen.
> 
> Neil pushed a fix yesterday that looks like it could fix your issue.
> The fix is: 1528038385c0 ("drm/bridge: dw-hdmi: use safe format when first in bridge chain")
> 
> Could you try if it does indeed fix your issue?

Sure.

Would have been nice and is a fix addressing same base commit, but is not a replacement for my attempt :(

Fortunately we can have both.

> 
> Cheers,
> -Paul
> 
>> This fix is based on the observation that max_bpc = 0 when running this
>> function while info->bpc = 8. Since the formats checks before this always test
>> for max_bpc >= info->pbc indirectly my assumption is that we must check it
>> here as well.
>> Adding the proposed patch makes the CI20/jz4780 panel work again in
>> MEDIA_BUS_FMT_RGB888_1X24 mode.
>> Fixes: 7cd70656d1285b ("drm/bridge: display-connector: implement bus fmts callbacks")
>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
>> ---
>> drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> index b0d8110dd412c..826a055a7a273 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -2620,10 +2620,10 @@ static u32 *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
>> 		output_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
>> 	}
>> -	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR422)
>> +	if (max_bpc >= info->bpc && info->color_formats & DRM_COLOR_FORMAT_YCBCR422)
>> 		output_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
>> -	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR444)
>> +	if (max_bpc >= info->bpc && info->color_formats & DRM_COLOR_FORMAT_YCBCR444)
>> 		output_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
>> 	/* Default 8bit RGB fallback */
>> --
>> 2.33.0
> 
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index b0d8110dd412c..826a055a7a273 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -2620,10 +2620,10 @@  static u32 *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
 		output_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
 	}
 
-	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR422)
+	if (max_bpc >= info->bpc && info->color_formats & DRM_COLOR_FORMAT_YCBCR422)
 		output_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
 
-	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR444)
+	if (max_bpc >= info->bpc && info->color_formats & DRM_COLOR_FORMAT_YCBCR444)
 		output_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
 
 	/* Default 8bit RGB fallback */