VD_OP_GET_DEVID
rv = vdc_do_op(vdc, VD_OP_GET_DEVID, (caddr_t)vd_devid,
rv = vdc_do_sync_op(vdc, VD_OP_GET_DEVID, (caddr_t)vd_devid,
{X(VD_OP_GET_DEVID), vd_get_devid, NULL},
(1 << VD_OP_GET_DEVID) | \