[PATCH] CHROMIUM: drm/rockchip: Disable blending for win0

[Kristian H. Kristensen]

Blending win0 with the background color doesn't seem to work
correctly. We only get the background color, no matter the contents of
the win0 framebuffer.  However, blending pre-multiplied color with the
default opaque black default background color is a no-op, so we can
just disable blending to get the correct result.

Signed-off-by: Kristian H. Kristensen <hoegsberg at chromium.org>
Cc: Sandy Huang <hjc at rock-chips.com>
Cc: Sean Paul <seanpaul at chromium.org>
---
As per Eric's suggestion, we can just disable blending. This replaces
the previous "Filter out alpha formats for primary plane" patch.

 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index fae37b1cd691..1c1dd11d489a 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -961,7 +961,14 @@ static void vop_plane_atomic_update(struct drm_plane *plane,
 	rb_swap = has_rb_swapped(fb->format->format);
 	VOP_WIN_SET(vop, win, rb_swap, rb_swap);
 
-	if (is_alpha_support(fb->format->format)) {
+	/*
+	 * Blending win0 with the background color doesn't seem to work
+	 * correctly. We only get the background color, no matter the contents
+	 * of the win0 framebuffer.  However, blending pre-multiplied color
+	 * with the default opaque black default background color is a no-op,
+	 * so we can just disable blending to get the correct result.
+	 */
+	if (is_alpha_support(fb->format->format) && win_index > 0) {
 		VOP_WIN_SET(vop, win, dst_alpha_ctl,
 			    DST_FACTOR_M0(ALPHA_SRC_INVERSE));
 		val = SRC_ALPHA_EN(1) | SRC_COLOR_M0(ALPHA_SRC_PRE_MUL) |
-- 
2.17.0.484.g0c8726318c-goog