drm/amd/display: fix issue where 252-255 values are clipped

[Why]
When endpoint is at the boundary of a region, such as at 2^0=1
we find that the last segment has a sharp slope and some points
are clipped at the top.

[How]
If end point is 1, which is exactly at the 2^0 region boundary, we
need to program an additional region beyond this point.

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
index 7469333..8166fdb 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
@@ -357,9 +357,10 @@ bool cm_helper_translate_curve_to_hw_format(
                seg_distr[7] = 4;
                seg_distr[8] = 4;
                seg_distr[9] = 4;
+               seg_distr[10] = 1;
 
                region_start = -10;
-               region_end = 0;
+               region_end = 1;
        }
 
        for (i = region_end - region_start; i < MAX_REGIONS_NUMBER ; i++)