drm/amd/display: Check ramp != NULL before applying lut1d for degamma

[Why]
A NULL ramp is a valid configuration for passing into
mod_color_calculate_degamma_params but we'll hit a NULL pointer if we do
so.

We need this in order to get the right transfer function to do degamma
on NV12 formats where we aren't supplied with a custom user degamma.

[How]
Add the NULL check.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Zhan Liu <Zhan.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 cac09d500fda938daa5899f44f0bdc87a2725ea5..d47253cdcc4e125d39225b412c83ef68dd1d94db 100644 (file)
--- a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
+++ b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c
@@ -1902,7 +1902,7 @@ bool mod_color_calculate_degamma_params(struct dc_transfer_func *input_tf,
 
 
 
-       if (ramp->type == GAMMA_CUSTOM)
+       if (ramp && ramp->type == GAMMA_CUSTOM)
                apply_lut_1d(ramp, MAX_HW_POINTS, tf_pts);
 
        ret = true;