diff options
| author | Melissa Wen <mwen@igalia.com> | 2026-01-22 12:20:29 -0300 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2026-02-03 17:21:43 -0500 |
| commit | 8f959d37c1f2efec6dac55915ee82302e98101fb (patch) | |
| tree | 6ad934c07c68c34a2d69ad8d8ad856e288266451 /drivers | |
| parent | 243b467dea1735fed904c2e54d248a46fa417a2d (diff) | |
drm/amd/display: fix wrong color value mapping on MCM shaper LUT
Some shimmer/colorful points appears when using the steamOS color
pipeline for HDR on gaming with DCN32. These points look like black
values being wrongly mapped to red/blue/green values. It was caused
because the number of hw points in regular LUTs and in a shaper LUT was
treated as the same.
DCN3+ regular LUTs have 257 bases and implicit deltas (i.e. HW
calculates them), but shaper LUT is a special case: it has 256 bases and
256 deltas, as in DCN1-2 regular LUTs, and outputs 14-bit values.
Fix that by setting by decreasing in 1 the number of HW points computed
in the LUT segmentation so that shaper LUT (i.e. fixpoint == true) keeps
the same DCN10 CM logic and regular LUTs go with `hw_points + 1`.
CC: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Fixes: 4d5fd3d08ea9 ("drm/amd/display: PQ tail accuracy")
Signed-off-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5006505b19a2119e71c008044d59f6d753c858b9)
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/dcn30/dcn30_cm_common.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_cm_common.c b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_cm_common.c index 0690c346f2c5..a4f14b16564c 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_cm_common.c +++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_cm_common.c @@ -163,6 +163,11 @@ bool cm3_helper_translate_curve_to_hw_format( hw_points += (1 << seg_distr[k]); } + // DCN3+ have 257 pts in lieu of no separate slope registers + // Prior HW had 256 base+slope pairs + // Shaper LUT (i.e. fixpoint == true) is still 256 bases and 256 deltas + hw_points = fixpoint ? (hw_points - 1) : hw_points; + j = 0; for (k = 0; k < (region_end - region_start); k++) { increment = NUMBER_SW_SEGMENTS / (1 << seg_distr[k]); @@ -223,8 +228,6 @@ bool cm3_helper_translate_curve_to_hw_format( corner_points[1].green.slope = dc_fixpt_zero; corner_points[1].blue.slope = dc_fixpt_zero; - // DCN3+ have 257 pts in lieu of no separate slope registers - // Prior HW had 256 base+slope pairs lut_params->hw_points_num = hw_points + 1; k = 0; |