[PATCH 5.2 045/137] drm/amd/display: fix issue where 252-255 values are clipped

[Greg Kroah-Hartman]

From: Anthony Koo <Anthony.Koo@xxxxxxx>

[ Upstream commit 1cbcfc975164f397b449efb17f59d81a703090db ]

[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@xxxxxxx>
Reviewed-by: Aric Cyr <Aric.Cyr@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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 7469333a2c8a5..8166fdbacd732 100644
--- 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++)
-- 
2.20.1