On 3/25/25 23:10, Vivek Kasireddy wrote:
> We need to save the reservation object pointer associated with the
> imported dmabuf in the newly created GEM object to allow
> drm_gem_plane_helper_prepare_fb() to extract the exclusive fence
> from it and attach it to the plane state during prepare phase.
> This is needed to ensure that drm_atomic_helper_wait_for_fences()
> correctly waits for the relevant fences (move, etc) associated with
> the reservation object, thereby implementing proper synchronization.
>
> Otherwise, artifacts or slight flickering can be seen when apps
> are dragged across the screen when running Gnome (Wayland). This
> problem is mostly seen with dGPUs in the case where the FBs are
> allocated in VRAM but need to be migrated to System RAM as they
> are shared with virtio-gpu.
>
> Fixes: ca77f27a2665 ("drm/virtio: Import prime buffers from other devices as
> guest blobs")
> Cc: Gerd Hoffmann <kra...@redhat.com>
> Cc: Dmitry Osipenko <dmitry.osipe...@collabora.com>
> Cc: Gurchetan Singh <gurchetansi...@chromium.org>
> Cc: Chia-I Wu <olva...@gmail.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasire...@intel.com>
> ---
> drivers/gpu/drm/virtio/virtgpu_prime.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c
> b/drivers/gpu/drm/virtio/virtgpu_prime.c
> index fe6a0b018571..ceb0401a000b 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_prime.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
> @@ -332,6 +332,7 @@ struct drm_gem_object *virtgpu_gem_prime_import(struct
> drm_device *dev,
> }
>
> obj->import_attach = attach;
> + obj->resv = buf->resv;
> get_dma_buf(buf);
>
> ret = virtgpu_dma_buf_init_obj(dev, bo, attach);
Will be better to set obj->resv before drm_gem_private_object_init()
since it checks whether obj->resv was pre-inited. I'll change it while
applying, thanks.
Reviewed-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
--
Best regards,
Dmitry
