[PATCH] drm/atomic: Set plane-state pixel_blend_mode to default

[Thomas Zimmermann <tzimmermann@suse.de>]

Initialize the plane state's pixel_blend_mode value to the plane
property's default value. Resolves an inconsistency on planes that
do not support PREMULTI.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 860e748bddcc ("drm: ensure blend mode supported if pixel format with alpha exposed")
Cc: Leandro Ribeiro <leandro.ribeiro@collabora.com>
Cc: Pekka Paalanen <pekka.paalanen@collabora.com>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
---
It's not clear what Fixes should point to, so I picked the commit that
introduced the stricter validation of the blend-mode property.
---
 drivers/gpu/drm/drm_atomic_state_helper.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index d90d1d7c9cf9..0325caee528a 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -278,7 +278,13 @@ void __drm_atomic_helper_plane_state_init(struct drm_plane_state *plane_state,
 	plane_state->rotation = DRM_MODE_ROTATE_0;
 
 	plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE;
-	plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
+
+	if (plane->blend_mode_property) {
+		if (!drm_object_property_get_default_value(&plane->base,
+							   plane->blend_mode_property,
+							   &val))
+			plane_state->pixel_blend_mode = val;
+	}
 
 	if (plane->color_encoding_property) {
 		if (!drm_object_property_get_default_value(&plane->base,
-- 
2.55.0