[PATCH 2/2] drm/verisilicon: set blend mode for the cursor plane

[Icenowy Zheng]

Blend mode properties are now required to expose pixel formats w/ alpha.

Experiments show that the fixed blending mode for the cursor seems to be
COVERAGE:

- With a cursor plane filled with R=G=0, B=0xff, A=0x40, the cursor is
  visible on a pure-white background, which means the background is
  multiplied.
- With a cursor plane filled with R=G=B=0xff, A=0x40, the cursor isn't
  pure white and non-white patterns can be see through, which means the
  cursor is multiplied.

Add a fixed COVERAGE blend mode property for the cursor plane.

Signed-off-by: Icenowy Zheng <zhengxingda@xxxxxxxxxxx>
---
 drivers/gpu/drm/verisilicon/vs_cursor_plane.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/verisilicon/vs_cursor_plane.c b/drivers/gpu/drm/verisilicon/vs_cursor_plane.c
index fa4f601dd0c87..36e3664373fa1 100644
--- a/drivers/gpu/drm/verisilicon/vs_cursor_plane.c
+++ b/drivers/gpu/drm/verisilicon/vs_cursor_plane.c
@@ -11,6 +11,7 @@
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_blend.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
@@ -268,5 +269,7 @@ struct drm_plane *vs_cursor_plane_init(struct drm_device *drm_dev,
 
 	drm_plane_helper_add(plane, &vs_cursor_plane_helper_funcs);
 
+	drm_plane_create_blend_mode_property(plane,
+					     BIT(DRM_MODE_BLEND_COVERAGE));
 	return plane;
 }
-- 
2.52.0