From: Vitaly Prosyak <vitaly.prosyak@amd.com>
Date: Tue, 13 Dec 2016 14:23:16 -0600
Subject: drm/amd/display: re gamma programming
Git-commit: 1e3d346f4fbb48f0a89134f4b834d3be2df3cc25
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Fix gamma update logic to avoid crash

Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1445,7 +1445,8 @@ void dc_update_surfaces_for_target(struc
 				}
 			}
 
-			if (updates[i].gamma) {
+			if (updates[i].gamma && updates[i].gamma !=
+				surface->public.gamma_correction) {
 				if (surface->public.gamma_correction != NULL)
 					dc_gamma_release(surface->public.
 							gamma_correction);