[PATCH v2 18/21] drm/amd/display: Fallback to 2020_YCBCR if the pixel encoding is not RGB

[Harry Wentland]

On 1/23/23 15:30, Sebastian Wick wrote:
> A new property to control YCC and subsampling would be the more
> complete path here. If we actually want to fix this in the short-term
> though, we should handle the YCC and RGB Colorspace values as
> equivalent, everywhere. Technically we're breaking the user space API
> here so it should be documented on the KMS property and other drivers
> must be adjusted accordingly as well.
> 

Could someone point me to a userspace that uses this currently?

Harry

> On Fri, Jan 13, 2023 at 5:26 PM Harry Wentland <harry.wentland at amd.com> wrote:
>>
>> From: Joshua Ashton <joshua at froggi.es>
>>
>> Userspace might not aware whether we're sending RGB or YCbCr
>> data to the display. If COLOR_SPACE_2020_RGB_FULLRANGE is
>> requested but the output encoding is YCbCr we should
>> send COLOR_SPACE_2020_YCBCR.
>>
>> Signed-off-by: Joshua Ashton <joshua at froggi.es>
>> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
>> Cc: Pekka Paalanen <ppaalanen at gmail.com>
>> Cc: Sebastian Wick <sebastian.wick at redhat.com>
>> Cc: Vitaly.Prosyak at amd.com
>> Cc: Joshua Ashton <joshua at froggi.es>
>> Cc: dri-devel at lists.freedesktop.org
>> Cc: amd-gfx at lists.freedesktop.org
>> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
>> ---
>>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> index f74b125af31f..16940ea61b59 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -5184,7 +5184,10 @@ get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing,
>>                 color_space = COLOR_SPACE_ADOBERGB;
>>                 break;
>>         case DRM_MODE_COLORIMETRY_BT2020_RGB:
>> -               color_space = COLOR_SPACE_2020_RGB_FULLRANGE;
>> +               if (dc_crtc_timing->pixel_encoding == PIXEL_ENCODING_RGB)
>> +                       color_space = COLOR_SPACE_2020_RGB_FULLRANGE;
>> +               else
>> +                       color_space = COLOR_SPACE_2020_YCBCR;
>>                 break;
>>         case DRM_MODE_COLORIMETRY_BT2020_YCC:
>>                 color_space = COLOR_SPACE_2020_YCBCR;
>> --
>> 2.39.0
>>
>