drm_client_framebuffer_flush
drm_client_framebuffer_flush(scanout->buffer, &r);
drm_client_framebuffer_flush(scanout->buffer, &r);
EXPORT_SYMBOL(drm_client_framebuffer_flush);
int drm_client_framebuffer_flush(struct drm_client_buffer *buffer, struct drm_rect *rect);