diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index 943db4f1bd6b4230c7eb1d5102fccf429a7112a3..4b370bc0746d8fc60273919946202cd2ee2973cc 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -458,8 +458,10 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
 	}
 
 	con = ovl_fmt_convert(ovl, fmt);
-	if (state->base.fb && state->base.fb->format->has_alpha)
-		con |= OVL_CON_AEN | OVL_CON_ALPHA;
+	if (state->base.fb) {
+		con |= OVL_CON_AEN;
+		con |= state->base.alpha & OVL_CON_ALPHA;
+	}
 
 	/* CONST_BLD must be enabled for XRGB formats although the alpha channel
 	 * can be ignored, or OVL will still read the value from memory.