[PATCH 2/2] drm: rcar-du: Enable alpha property on primary planes

[Kieran Bingham]

If the alpha property is not added to a plane, a default value will be
used, which can result in a non-visible layer if the alpha is
initialised as 0.

Provide an alpha blend property on all planes.

Fixes: 161ad653d6c9 ("drm: rcar-du: Use __drm_atomic_helper_plane_reset
instead of copying the logic")

Signed-off-by: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_plane.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_plane.c b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
index 9e07758a755c..72399a19d8a6 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_plane.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
@@ -783,13 +783,18 @@ int rcar_du_planes_init(struct rcar_du_group *rgrp)
 		drm_plane_helper_add(&plane->plane,
 				     &rcar_du_plane_helper_funcs);
 
+		/*
+		 * The alpha property needs to be initialised on all planes
+		 * to ensure the correct setting at the output.
+		 */
+		drm_plane_create_alpha_property(&plane->plane);
+
 		if (type == DRM_PLANE_TYPE_PRIMARY)
 			continue;
 
 		drm_object_attach_property(&plane->plane.base,
 					   rcdu->props.colorkey,
 					   RCAR_DU_COLORKEY_NONE);
-		drm_plane_create_alpha_property(&plane->plane);
 		drm_plane_create_zpos_property(&plane->plane, 1, 1, 7);
 	}
 
-- 
2.17.1