[PATCH] drm/virtio: add overlay plane format support

From: Baorui . Liu

Date: Thu Sep 24 2026 - 10:42:33 EST


From: Sophia Gong <lili.gong@xxxxxxx>

Advertise additional pixel formats for virtio-gpu overlay planes so a
userspace compositor can use KMS overlay composition instead of
falling back to GPU composition.

Handle DRM_PLANE_TYPE_OVERLAY in virtio_gpu_plane_init() with a
dedicated format list, and reuse the primary plane update path for
overlay scanout.

Signed-off-by: Sophia Gong <lili.gong@xxxxxxx>
Signed-off-by: Baorui.Liu <baorliu@xxxxxxx>
---
drivers/gpu/drm/virtio/virtgpu_plane.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index 29e4b458ae57..23ca880692f1 100644
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -41,6 +41,21 @@ static const uint32_t virtio_gpu_cursor_formats[] = {
DRM_FORMAT_HOST_ARGB8888,
};

+static const uint32_t virtio_gpu_overlay_formats[] = {
+ DRM_FORMAT_XRGB8888,
+ DRM_FORMAT_ARGB8888,
+ DRM_FORMAT_BGRX8888,
+ DRM_FORMAT_BGRA8888,
+ DRM_FORMAT_RGBX8888,
+ DRM_FORMAT_RGBA8888,
+ DRM_FORMAT_XBGR8888,
+ DRM_FORMAT_ABGR8888,
+ DRM_FORMAT_XRGB2101010,
+ DRM_FORMAT_BGRX1010102,
+ DRM_FORMAT_NV12,
+ DRM_FORMAT_P010,
+};
+
uint32_t virtio_gpu_translate_format(uint32_t drm_fourcc)
{
uint32_t format;
@@ -572,6 +587,13 @@ static const struct drm_plane_helper_funcs virtio_gpu_cursor_helper_funcs = {
.atomic_update = virtio_gpu_cursor_plane_update,
};

+static const struct drm_plane_helper_funcs virtio_gpu_overlay_helper_funcs = {
+ .prepare_fb = virtio_gpu_plane_prepare_fb,
+ .cleanup_fb = virtio_gpu_plane_cleanup_fb,
+ .atomic_check = virtio_gpu_plane_atomic_check,
+ .atomic_update = virtio_gpu_primary_plane_update,
+};
+
struct drm_plane *virtio_gpu_plane_init(struct virtio_gpu_device *vgdev,
enum drm_plane_type type,
int index)
@@ -586,6 +608,10 @@ struct drm_plane *virtio_gpu_plane_init(struct virtio_gpu_device *vgdev,
formats = virtio_gpu_cursor_formats;
nformats = ARRAY_SIZE(virtio_gpu_cursor_formats);
funcs = &virtio_gpu_cursor_helper_funcs;
+ } else if (type == DRM_PLANE_TYPE_OVERLAY) {
+ formats = virtio_gpu_overlay_formats;
+ nformats = ARRAY_SIZE(virtio_gpu_overlay_formats);
+ funcs = &virtio_gpu_overlay_helper_funcs;
} else {
formats = virtio_gpu_formats;
nformats = ARRAY_SIZE(virtio_gpu_formats);
--
2.25.1