[PATCH] drm/exynos: Don't blend mixer layer 0

[Sean Paul]

This patch disables blending the mixer's layer 0 onto the background
(solid color). It doesn't make sense to blend this layer by default,
and causes color distortion if the layer is used for arbitrary content.

Signed-off-by: Sean Paul <seanpaul at chromium.org>
---
 drivers/gpu/drm/exynos/exynos_mixer.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index f08e251..ec3e376 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -643,12 +643,14 @@ static void mixer_win_reset(struct mixer_context *ctx)
 	/* setting graphical layers */
 	val  = MXR_GRP_CFG_COLOR_KEY_DISABLE; /* no blank key */
 	val |= MXR_GRP_CFG_WIN_BLEND_EN;
-	val |= MXR_GRP_CFG_BLEND_PRE_MUL;
-	val |= MXR_GRP_CFG_PIXEL_BLEND_EN;
 	val |= MXR_GRP_CFG_ALPHA_VAL(0xff); /* non-transparent alpha */
 
-	/* the same configuration for both layers */
+	/* Don't blend layer 0 onto the mixer background */
 	mixer_reg_write(res, MXR_GRAPHIC_CFG(0), val);
+
+	/* Blend layer 1 into layer 0 */
+	val |= MXR_GRP_CFG_BLEND_PRE_MUL;
+	val |= MXR_GRP_CFG_PIXEL_BLEND_EN;
 	mixer_reg_write(res, MXR_GRAPHIC_CFG(1), val);
 
 	/* setting video layers */
-- 
1.7.7.3