DP_PSR_ESI
r = drm_dp_dpcd_readb(&intel_dp->aux, DP_PSR_ESI, &val);
drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_ESI, val);
drm_dp_dpcd_read(link->aux, DP_PSR_ESI, &status, 1);