[PATCH v4 2/5] drm/mediatek: Support "None" blending in Mixer

[Hsiao Chien Sung via B4 Relay <devnull+shawn.sung.mediatek.com@kernel.org>]

From: Hsiao Chien Sung <shawn.sung@mediatek.com>

Support "None" alpha blending mode on MediaTek's chips.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_ethdr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index 9dfd13d32dfa..80ccdad3741b 100644
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2021 MediaTek Inc.
  */
 
+#include <drm/drm_blend.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
 #include <linux/clk.h>
@@ -175,7 +176,8 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
 		alpha_con |= state->base.alpha & MIXER_ALPHA;
 	}
 
-	if (state->base.fb && !state->base.fb->format->has_alpha) {
+	if ((state->base.fb && !state->base.fb->format->has_alpha) ||
+	    state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
 		/*
 		 * Mixer doesn't support CONST_BLD mode,
 		 * use a trick to make the output equivalent

-- 
2.43.0