drm_client_modeset_wait_for_vblank
EXPORT_SYMBOL(drm_client_modeset_wait_for_vblank);
drm_client_modeset_wait_for_vblank(&helper->client, 0);
ret = drm_client_modeset_wait_for_vblank(&fb_helper->client, 0);
int drm_client_modeset_wait_for_vblank(struct drm_client_dev *client, unsigned int crtc_index);