[PATCH 10/24] drm/amd/display: Rework CRTC color management

Michel Dänzer michel at daenzer.net
Fri Jun 7 07:58:33 UTC 2019

On 2019-06-06 10:54 p.m., Bhawanpreet Lakha wrote:
> From: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> [Why]
> To prepare for the upcoming DRM plane color management properties
> we need to correct a lot of wrong behavior and assumptions made for
> CRTC color management.
> The documentation added by this commit in amdgpu_dm_color explains
> how the HW color pipeline works and its limitations with the DRM
> interface.
> The current implementation does the following wrong:
> - Implicit sRGB DGM when no CRTC DGM is set
> - Implicit sRGB RGM when no CRTC RGM is set
> - No way to specify a non-linear DGM matrix that produces correct output
> - No way to specify a correct RGM when a linear DGM is used
> We had workarounds for passing kms_color tests but not all of the
> behavior we had wrong was covered by these tests (especially when
> it comes to non-linear DGM). Testing both DGM and RGM at the same time
> isn't something kms_color tests well either.
> [How]
> The specifics for how color management works in AMDGPU and the new
> behavior can be found by reading the documentation added to
> amdgpu_dm_color.c from this patch.
> All of the incorrect cases from the old implementation have been
> addressed for the atomic interface, but there still a few TODOs for
> the legacy one.
> Note: this does cause regressions for kms_color at pipe-a-ctm-* over HDMI.
> The result looks correct from visual inspection but the CRC no longer
> matches. For reference, the test was previously doing the following:
> linear degamma -> CTM -> sRGB regamma -> RGB to YUV (709) -> ...
> Now the test is doing:
> linear degamma -> CTM -> linear regamma -> RGB to YUV (709) -> ...
> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> Reviewed-by: Sun peng Li <Sunpeng.Li at amd.com>
> Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>

Does this address https://bugs.freedesktop.org/110677 ? If so, can you
add a reference to the commit log?

Earthling Michel Dänzer               |              https://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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