[PATCH 15/21] drm/amd/display: Limit user regamma to a valid value

[Pavle Kotarac]

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

[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.

Reviewed-by: Krunoslav Kovac <krunoslav.ko...@amd.com>
Reviewed-by: Krunoslav Kovac <krunoslav.ko...@amd.com>
Reviewed-by: Aric Cyr <aric....@amd.com>
Acked-by: Pavle Kotarac <pavle.kota...@amd.com>
Signed-off-by: Yao Wang1 <yao.wa...@amd.com>
---
 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 859ffd8725c5..04f7656906ca 100644
--- a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
+++ b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
@@ -1600,6 +1600,7 @@ 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 */
@@ -1628,6 +1629,9 @@ 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)
-- 
2.34.1