tty_getlock
callout_init_mtx(&cfe_timer, tty_getlock(tp), 0);
callout_init_mtx(&ofw_timer, tty_getlock(tp), 0);
error = cv_wait_sig(&ss->snp_outwait, tty_getlock(tp));
return (tty_getlock(sc->sc_u.u_tty.tp));
callout_init_mtx(&cons->callout, tty_getlock(tp), 0);
callout_init_mtx(&conscallout, tty_getlock(tp), 0);