This is a note to let you know that I've just added the patch titled
drm/amd/display: Limit user regamma to a valid value
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-limit-user-regamma-to-a-valid-value.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 692d5c83e8db0d714083d508a62a92648ed8c1d5
Author: Yao Wang1 <Yao.Wang1@xxxxxxx>
Date: Mon Aug 22 18:30:31 2022 +0800
drm/amd/display: Limit user regamma to a valid value
[ Upstream commit 3601d620f22e37740cf73f8278eabf9f2aa19eb7 ]
[Why]
For HDR mode, we get total 512 tf_point and after switching to SDR mode
we actually get 400 tf_point and the rest of points(401~512) still use
dirty value from HDR mode. We should limit the rest of the points to max
value.
[How]
Limit the value when coordinates_x.x > 1, just like what we do in
translate_from_linear_space for other re-gamma build paths.
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@xxxxxxx>
Reviewed-by: Aric Cyr <Aric.Cyr@xxxxxxx>
Acked-by: Pavle Kotarac <Pavle.Kotarac@xxxxxxx>
Signed-off-by: Yao Wang1 <Yao.Wang1@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
index 11ea1a0e629b..4e866317ec25 100644
--- a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
+++ b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
@@ -1206,6 +1206,7 @@ static void interpolate_user_regamma(uint32_t hw_points_num,
struct fixed31_32 lut2;
struct fixed31_32 delta_lut;
struct fixed31_32 delta_index;
+ const struct fixed31_32 one = dc_fixpt_from_int(1);
i = 0;
/* fixed_pt library has problems handling too small values */
@@ -1234,6 +1235,9 @@ static void interpolate_user_regamma(uint32_t hw_points_num,
} else
hw_x = coordinates_x[i].x;
+ if (dc_fixpt_le(one, hw_x))
+ hw_x = one;
+
norm_x = dc_fixpt_mul(norm_factor, hw_x);
index = dc_fixpt_floor(norm_x);
if (index < 0 || index > 255)
