drm/amd/display: PQ regamma end point

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[WHY & HOW]
PQ has a fixed range of 0-10,000 nits.
Using 1=80 nits normalization, PQ should map to 1.0 for X=125.0
HW LUT used for interpolation does not have X=125 so it's interpolated.
However, we cap Y to 1 for all X>=125.

The closest larger HW point is 128.
What we want is Y(128) such that interpolation through 125 gives 1.0.
Such value is ~1.00256.
Another change is to hardcode PQ table, we pretty much always have 1=80
normalization so the table can be static.

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Krunoslav Kovac <krunoslav.kovac@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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Krunoslav Kovac 2023-08-08 16:38:56 -04:00 • committed by Alex Deucher

parent 4d5fd3d08e

commit 959d2fc47f

1 changed files with 109 additions and 6 deletions

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drivers/gpu/drm/amd/display/modules/color/color_gamma.c

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