On 10/1/26 21:00, Marek Szyprowski wrote: > On 20.09.2026 20:21, Dmitry Osipenko wrote: >> On 8/28/26 12:01, [email protected] wrote: >>> From: Shixiong Ou <[email protected]> >>> >>> The cursor plane exposes a format with an alpha channel >>> (DRM_FORMAT_ARGB8888) without a pixel blend mode property. Since >>> commit 860e748bddcc ("drm: ensure blend mode supported if pixel >>> format with alpha exposed") this triggers a warning during >>> drm_mode_config_validate(): >>> >>> [ 0.649020] ------------[ cut here ]------------ >>> [ 0.649040] [PLANE:36:plane-1] pixel format with alpha exposed but blend >>> mode not setup >>> [ 0.649081] WARNING: drivers/gpu/drm/drm_mode_config.c:872 at >>> drm_mode_config_validate >>> ...... >>> [ 0.649761] Call trace: >>> [ 0.649764] drm_mode_config_validate+0x398/0x558 [drm] (P) >>> [ 0.649912] drm_dev_register+0x1cc/0x2a0 [drm] >>> [ 0.650058] virtio_gpu_probe+0xd4/0x1c0 [virtio_gpu] >>> [ 0.650088] virtio_dev_probe+0x1c8/0x310 >>> ...... >>> [ 0.650261] ---[ end trace 0000000000000000 ]--- >>> >>> >>> Create the property with the only supported blend mode, >>> DRM_MODE_BLEND_PREMULTI, which is also the property's default and >>> matches what userspace had to assume before the property existed. >>> >>> Reported-by: Ye Liu <[email protected]> >>> Signed-off-by: Shixiong Ou <[email protected]> >>> --- >>> drivers/gpu/drm/virtio/virtgpu_plane.c | 14 ++++++++++++++ >>> 1 file changed, 14 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c >>> b/drivers/gpu/drm/virtio/virtgpu_plane.c >>> index 1d1b27ece62a..11771c943ea6 100644 >>> --- a/drivers/gpu/drm/virtio/virtgpu_plane.c >>> +++ b/drivers/gpu/drm/virtio/virtgpu_plane.c >>> @@ -24,6 +24,7 @@ >>> */ >>> >>> #include <drm/drm_atomic_helper.h> >>> +#include <drm/drm_blend.h> >>> #include <drm/drm_damage_helper.h> >>> #include <drm/drm_fourcc.h> >>> #include <drm/drm_gem_atomic_helper.h> >>> @@ -588,6 +589,7 @@ struct drm_plane *virtio_gpu_plane_init(struct >>> virtio_gpu_device *vgdev, >>> struct drm_plane *plane; >>> const uint32_t *formats; >>> int nformats; >>> + int ret; >>> >>> if (type == DRM_PLANE_TYPE_CURSOR) { >>> formats = virtio_gpu_cursor_formats; >>> @@ -610,5 +612,17 @@ struct drm_plane *virtio_gpu_plane_init(struct >>> virtio_gpu_device *vgdev, >>> if (type == DRM_PLANE_TYPE_PRIMARY) >>> drm_plane_enable_fb_damage_clips(plane); >>> >>> + if (type == DRM_PLANE_TYPE_CURSOR) { >>> + /* >>> + * The cursor plane exposes a format with an alpha channel, >>> + * which requires a blend mode property. The host blends >>> + * premultiplied alpha, matching the property's default. >>> + */ >>> + ret = drm_plane_create_blend_mode_property(plane, >>> + >>> BIT(DRM_MODE_BLEND_PREMULTI)); >>> + if (ret) >>> + return ERR_PTR(ret); >>> + } >>> + >>> return plane; >>> } >> Applied to misc-fixes, thanks! > > > This duplicates commit f2e64f450c16 ("drm/virtio: create blend mode property > on cursor > plane") merged a bit earlier, what in turn results in double call to > drm_plane_create_blend_mode_property() what confuses userspace (modetest tool > crashes). Good catch, will revert this patch. Thanks!
-- Best regards, Dmitry
