Reviewed-by: Alex Hung <alex.hung@amd.com>
On 8/29/26 21:51, Satyajit Roy wrote:
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> From: Satyajit Roy <sroy14@alum.utk.edu>
>
> The Broadcast RGB implementation currently has three gaps in the AMD
> Display path:
>
> 1. DM does not propagate the sink's RGB quantization-range
> selectability into DC, so the HDMI AVI InfoFrame Q field remains at
> its default value.
> 2. BT.2020 RGB output is always selected as full range, so an explicit
> Limited setting has no effect in HDR modes using BT.2020 RGB.
> 3. A property-only range transition updates the output CSC but does not
> rebuild and program the InfoFrame, leaving the sink with stale range
> signaling.
>
> Together these can make the transmitted pixel range and the range inferred
> by a television's automatic black-level setting disagree.
>
> Patch 1 propagates the EDID QS capability. Patch 2 honors Limited for
> BT.2020 RGB and adds KUnit coverage for both BT.2020 connector colorspace
> values. Patch 3 rebuilds InfoFrames whenever output_color_space changes.
>
> Validation performed on amd-staging-drm-next at the base commit below:
>
> - scripts/checkpatch.pl --strict: no errors, warnings, or checks
> - x86_64 AMD Display KUnit configuration built with CONFIG_WERROR=y
> - new EDID-capability and BT.2020 quantization KUnit cases compiled
>
> Equivalent changes were also tested on an HDMI 2.1 television with a
> Valve Linux 7.2 kernel. The television's automatic black-level selection
> followed Full-to-Limited and Limited-to-Full transitions in SDR, HDR, and
> HDR with VRR active. No modeset or visible link blank was observed.
>
> Satyajit Roy (3):
> drm/amd/display: Propagate HDMI RGB quantization selectability
> drm/amd/display: Honor Broadcast RGB for BT.2020 RGB output
> drm/amd/display: Rebuild InfoFrames on output color space changes
>
> .../display/amdgpu_dm/amdgpu_dm_connector.c | 10 +++--
> .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 1 +
> .../tests/amdgpu_dm_connector_test.c | 37 +++++++++++++++++++
> .../amdgpu_dm/tests/amdgpu_dm_helpers_test.c | 2 +
> drivers/gpu/drm/amd/display/dc/core/dc.c | 3 ++
> 5 files changed, 50 insertions(+), 3 deletions(-)
>
>
> base-commit: 75a5e1b6b3661c3f946885d01eebeb6b031035ef
> --
> 2.51.1