[PATCH 5.15 129/148] drm/amd/display: Limit user regamma to a valid value

Greg Kroah-Hartman
2022-09-26T11:28:30Z

From: Yao Wang1 <Yao.Wang1@amd.com>

[ 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@amd.com>
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Signed-off-by: Yao Wang1 <Yao.Wang1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/modules/color/color_gamma.c | 4 ++++
1 file changed, 4 insertions(+)

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 ef742d95ef05..c707c9bfed43 100644
--- a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
+++ b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
@@ -1597,6 +1597,7 @@ 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 */
@@ -1625,6 +1626,9 @@ 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)
--
2.35.1