SCN_SW_SOFTCAR
if ((sc->sc_swflags & SCN_SW_SOFTCAR) || /* check ttyflags */
if ((tp->t_cflag & HUPCL) && (sc->sc_swflags & SCN_SW_SOFTCAR) == 0) {
if (sc->sc_swflags & SCN_SW_SOFTCAR)
if (sc->sc_swflags & SCN_SW_SOFTCAR)
driverbits |= SCN_SW_SOFTCAR;
sc->sc_swflags |= SCN_SW_SOFTCAR; /* ignore carrier */