[PATCH 08/22] drm/amd/display: fix a dereference of a NULL pointer

[Tom Chung]

From: Wenjing Liu <wenjing.liu at amd.com>

[why&how]
In some platform out_transfer_func may not be popualted. We need to check
for null before dereferencing it.

Fixes: 4b939f625e9b ("drm/amd/display: Generalize new minimal transition path")
Reviewed-by: Alvin Lee <alvin.lee2 at amd.com>
Acked-by: Tom Chung <chiahsuan.chung at amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index dd9fe36646a3..726c82be16fa 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -3057,7 +3057,8 @@ static void backup_planes_and_stream_state(
 		scratch->blend_tf[i] = *status->plane_states[i]->blend_tf;
 	}
 	scratch->stream_state = *stream;
-	scratch->out_transfer_func = *stream->out_transfer_func;
+	if (stream->out_transfer_func)
+		scratch->out_transfer_func = *stream->out_transfer_func;
 }
 
 static void restore_planes_and_stream_state(
@@ -3079,7 +3080,8 @@ static void restore_planes_and_stream_state(
 		*status->plane_states[i]->blend_tf = scratch->blend_tf[i];
 	}
 	*stream = scratch->stream_state;
-	*stream->out_transfer_func = scratch->out_transfer_func;
+	if (stream->out_transfer_func)
+		*stream->out_transfer_func = scratch->out_transfer_func;
 }
 
 /**
-- 
2.34.1