[PATCH v3, 08/15] drm/mediatek: check if fb is null

[Yongqiang Niu]

It's possible that state->base.fb is null. Add a check before access its
format.

Fixes: b6b1bb980ec4 ( drm/mediatek: Turn off Alpha bit when plane format has no alpha)
Signed-off-by: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index 4934bee..8e7f494 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -279,7 +279,7 @@ static void mtk_ovl_layer_config(struct mtk_ddp_comp *comp, unsigned int idx,
 	}
 
 	con = ovl_fmt_convert(ovl, fmt);
-	if (state->base.fb->format->has_alpha)
+	if (state->base.fb && state->base.fb->format->has_alpha)
 		con |= OVL_CON_AEN | OVL_CON_ALPHA;
 
 	if (pending->rotation & DRM_MODE_REFLECT_Y) {
-- 
1.8.1.1.dirty