UCOM_OPEN
sc->sc_state = UCOM_OPEN;
KASSERTMSG(sc->sc_state == UCOM_ATTACHED || sc->sc_state == UCOM_OPEN,
if (sc->sc_state != UCOM_OPEN && !ucom_polling(sc)) {
KASSERTMSG(state == UCOM_OPEN || state == UCOM_ATTACHED,