drm_dp_dpcd_access
ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, DP_DPCD_REV, buffer,
ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, offset, buffer,
ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_WRITE, offset, buffer,