Re: [Intel-gfx] [PATCH v4 17/17] drm/amd/display: Add handling for new "Broadcast RGB" property

Werner Sembach
2021-06-22T09:29:06Z

Am 22.06.21 um 09:29 schrieb Pekka Paalanen:
> On Fri, 18 Jun 2021 11:11:16 +0200
> Werner Sembach <wse@tuxedocomputers.com> wrote:
>
>> This commit implements the "Broadcast RGB" drm property for the AMD GPU
>> driver.
>>
>> Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
>> ---
>> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 22 ++++++++++++++-----
>> .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 4 ++++
>> 2 files changed, 21 insertions(+), 5 deletions(-)
>>
>> 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 9ffd2f9d3d75..c5dbf948a47a 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -5252,7 +5252,8 @@ get_aspect_ratio(const struct drm_display_mode *mode_in)
>> }
>>
>> static enum dc_color_space
>> -get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing)
>> +get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing,
>> + enum drm_mode_color_range preferred_color_range)
>> {
>> enum dc_color_space color_space = COLOR_SPACE_SRGB;
>>
>> @@ -5267,13 +5268,17 @@ get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing)
>> * respectively
>> */
>> if (dc_crtc_timing->pix_clk_100hz > 270300) {
>> - if (dc_crtc_timing->flags.Y_ONLY)
>> + if (dc_crtc_timing->flags.Y_ONLY
>> + || preferred_color_range ==
>> + DRM_MODE_COLOR_RANGE_LIMITED_16_235)
>> color_space =
>> COLOR_SPACE_YCBCR709_LIMITED;
>> else
>> color_space = COLOR_SPACE_YCBCR709;
> Hi,
>
> does this mean that amdgpu would be using a property named "Broadcast
> RGB" to control the range of YCbCr too?

Yes, because I avoided creating a new property, but I'm not really happy with it either.

Possibility 1: Use "Broadcast RGB" for Y'CbCr too and clarify in documentation
- still confusing name
- limited does not mean something a little bit different for Y'CbCr and not strictly 16-235:
https://www.kernel.org/doc/html/v5.12/userspace-api/media/v4l/colorspaces-defs.html#c.V4L.v4l2_quantization , but name
of option is given by preexisting property

Possibility 2: Deprecate "Broadcast RGB" and a a more neutral sounding "preferred color range", with the more neutral
sounding "limited" option instead of "Limited 16:235"
- What's the relation between the 2? pq mentioned on the amdgpu gitlab that there is a posibility for userspace to
have only the new or the old one shown
- Alternatively ignore "Broadcast RGB" when "preferred color range" is set and have them coexist?

>
> That is surprising. If this is truly wanted, then the documentation of
> "Broadcast RGB" must say that it applies to YCbCr too.
>
> Does amdgpu do the same as intel wrt. to the question about whose
> responsibility it is to make the pixels at the connector to match the
> set range?

I guess the kernel driver does the conversion, but i have to check for both.

For Intel I did not change the behavior of Boradcast RGB, but i think it's not clearly specified in the docs where the
conversion happens.

>
>
> Thanks,
> pq
>
>> } else {
>> - if (dc_crtc_timing->flags.Y_ONLY)
>> + if (dc_crtc_timing->flags.Y_ONLY
>> + || preferred_color_range ==
>> + DRM_MODE_COLOR_RANGE_LIMITED_16_235)
>> color_space =
>> COLOR_SPACE_YCBCR601_LIMITED;
>> else
>> @@ -5283,7 +5288,10 @@ get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing)
>> }
>> break;
>> case PIXEL_ENCODING_RGB:
>> - color_space = COLOR_SPACE_SRGB;
>> + if (preferred_color_range == DRM_MODE_COLOR_RANGE_LIMITED_16_235)
>> + color_space = COLOR_SPACE_SRGB_LIMITED;
>> + else
>> + color_space = COLOR_SPACE_SRGB;
>> break;
>>
>> default:
>> @@ -5429,7 +5437,10 @@ static void fill_stream_properties_from_drm_display_mode(
>>
>> timing_out->aspect_ratio = get_aspect_ratio(mode_in);
>>
>> - stream->output_color_space = get_output_color_space(timing_out);
>> + stream->output_color_space = get_output_color_space(timing_out,
>> + connector_state ?
>> + connector_state->preferred_color_range :
>> + DRM_MODE_COLOR_RANGE_UNSET);
>>
>> stream->out_transfer_func->type = TF_TYPE_PREDEFINED;
>> stream->out_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
>> @@ -7780,6 +7791,7 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
>> drm_connector_attach_active_bpc_property(&aconnector->base, 8, 16);
>> drm_connector_attach_preferred_color_format_property(&aconnector->base);
>> drm_connector_attach_active_color_format_property(&aconnector->base);
>> + drm_connector_attach_preferred_color_range_property(&aconnector->base);
>> drm_connector_attach_active_color_range_property(&aconnector->base);
>> }
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
>> index 2563788ba95a..80e1389fd0ec 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
>> @@ -421,6 +421,10 @@ dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
>> if (connector->active_color_format_property)
>> drm_connector_attach_active_color_format_property(&aconnector->base);
>>
>> + connector->preferred_color_range_property = master->base.preferred_color_range_property;
>> + if (connector->preferred_color_range_property)
>> + drm_connector_attach_preferred_color_range_property(&aconnector->base);
>> +
>> connector->active_color_range_property = master->base.active_color_range_property;
>> if (connector->active_color_range_property)
>> drm_connector_attach_active_color_range_property(&aconnector->base);
> _______________________________________________
> amd-gfx mailing list
> amd-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx