[RFC PATCH 3/3] drm/virtio: drm_gem_plane_helper_prepare_fb for obj synchronization

[Dongwon Kim <dongwon.kim@intel.com>]

This helper is needed for framebuffer synchronization. Old framebuffer data
is often displayed on the guest display without this helper.

Cc: Gurchetan Singh <gurchetansingh@chromium.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
 drivers/gpu/drm/virtio/virtgpu_plane.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index 51b14ee4ece9..968afd0029fa 100644
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -26,6 +26,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_damage_helper.h>
 #include <drm/drm_fourcc.h>
+#include <drm/drm_gem_atomic_helper.h>
 
 #include "virtgpu_drv.h"
 
@@ -270,6 +271,9 @@ static int virtio_gpu_plane_prepare_fb(struct drm_plane *plane,
 	vgfb = to_virtio_gpu_framebuffer(new_state->fb);
 	vgplane_st = to_virtio_gpu_plane_state(new_state);
 	bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]);
+
+	drm_gem_plane_helper_prepare_fb(plane, new_state);
+
 	if (!bo || (plane->type == DRM_PLANE_TYPE_PRIMARY && !bo->guest_blob))
 		return 0;
 
-- 
2.20.1