[PATCH] [PATCH] drm/vkms: Advertise PREMULTI blend mode

[Michail Tatas]

Since we only support pre-multiplied alpha blend mode,
advertise that, otherwise validate_blend_mode_for_alpha_formats()
will throw a WARN.

Reported-by: syzbot+6245cb95ae707991bffa@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Michail Tatas <michail.tatas@xxxxxxxxx>
---

syzbot link: https://syzkaller.appspot.com/bug?extid=6245cb95ae707991bffa

 drivers/gpu/drm/vkms/vkms_plane.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 68cb2a3335e6..a2e5ebee729a 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -246,6 +246,12 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 					  DRM_COLOR_YCBCR_BT601,
 					  DRM_COLOR_YCBCR_FULL_RANGE);
 
+	/* Since our composer only supports pre-multiplied alpha,
+	 * advertise only the PREMULTI blend mode.
+	 */
+	drm_plane_create_blend_mode_property(&plane->base,
+					BIT(DRM_MODE_BLEND_PREMULTI));
+
 	if (vkms_config_plane_get_default_pipeline(plane_cfg))
 		vkms_initialize_colorops(&plane->base);
 
-- 
2.43.0