[PATCH v2 02/14] drm/mediatek: Disable 9-bit alpha in ETHDR

[Hsiao Chien Sung via B4 Relay]

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

When 9-bit alpha is enabled, its value will be converted from 0-255 to
0-256 (255 = not defined). This is designed for special HDR related
calculation, which should be disabled by default, otherwise, alpha
blending will not work correctly.

Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
Reviewed-by: CK Hu <ck.hu at mediatek.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung at mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_ethdr.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index 156c6ff547e8..d7d16482c947 100644
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -50,7 +50,6 @@
 
 #define MIXER_INX_MODE_BYPASS			0
 #define MIXER_INX_MODE_EVEN_EXTEND		1
-#define DEFAULT_9BIT_ALPHA			0x100
 #define	MIXER_ALPHA_AEN				BIT(8)
 #define	MIXER_ALPHA				0xff
 #define ETHDR_CLK_NUM				13
@@ -169,7 +168,7 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
 		alpha_con = MIXER_ALPHA_AEN | MIXER_ALPHA;
 
 	mtk_mmsys_mixer_in_config(priv->mmsys_dev, idx + 1, alpha_con ? false : true,
-				  DEFAULT_9BIT_ALPHA,
+				  MIXER_ALPHA,
 				  pending->x & 1 ? MIXER_INX_MODE_EVEN_EXTEND :
 				  MIXER_INX_MODE_BYPASS, align_width / 2 - 1, cmdq_pkt);
 

-- 
Git-146)