DPCD_LC15_LINK_RATE_SET
ret = nvkm_rdaux(outp->dp.aux, DPCD_LC15_LINK_RATE_SET, &sink[0], sizeof(sink[0]));
ret = nvkm_wraux(outp->dp.aux, DPCD_LC15_LINK_RATE_SET, &sink[0], sizeof(sink[0]));