diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index a6ed98f86297..5cdaa10728d6 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1467,6 +1467,7 @@ tty_signal_sessleader(struct tty *tp, int sig)
 
 	/* Make signals start output again. */
 	tp->t_flags &= ~TF_STOPPED;
+	tp->t_termios.c_lflag &= ~FLUSHO;
 
 	if (tp->t_session != NULL && tp->t_session->s_leader != NULL) {
 		p = tp->t_session->s_leader;
@@ -1486,6 +1487,7 @@ tty_signal_pgrp(struct tty *tp, int sig)
 
 	/* Make signals start output again. */
 	tp->t_flags &= ~TF_STOPPED;
+	tp->t_termios.c_lflag &= ~FLUSHO;
 
 	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
 		tty_info(tp);
@@ -1930,6 +1932,7 @@ tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
 		return (0);
 	case TIOCSTART:
 		tp->t_flags &= ~TF_STOPPED;
+		tp->t_termios.c_lflag &= ~FLUSHO;
 		ttydevsw_outwakeup(tp);
 		ttydevsw_pktnotify(tp, TIOCPKT_START);
 		return (0);
diff --git a/sys/kern/tty_ttydisc.c b/sys/kern/tty_ttydisc.c
index 0e3c785545a1..546b610010a3 100644
--- a/sys/kern/tty_ttydisc.c
+++ b/sys/kern/tty_ttydisc.c
@@ -95,6 +95,7 @@ ttydisc_close(struct tty *tp)
 
 	/* Clean up our flags when leaving the discipline. */
 	tp->t_flags &= ~(TF_STOPPED|TF_HIWAT|TF_ZOMBIE);
+	tp->t_termios.c_lflag &= ~FLUSHO;
 
 	/*
 	 * POSIX states that we must drain output and flush input on
@@ -474,6 +475,12 @@ ttydisc_write(struct tty *tp, struct uio *uio, int ioflag)
 
 		MPASS(oblen == 0);
 
+		if (CMP_FLAG(l, FLUSHO)) {
+			uio->uio_offset += uio->uio_resid;
+			uio->uio_resid = 0;
+			return (0);
+		}
+
 		/* Step 1: read data. */
 		obstart = ob;
 		nlen = MIN(uio->uio_resid, sizeof ob);
@@ -495,6 +502,12 @@ ttydisc_write(struct tty *tp, struct uio *uio, int ioflag)
 		do {
 			unsigned int plen, wlen;
 
+			if (CMP_FLAG(l, FLUSHO)) {
+				uio->uio_offset += uio->uio_resid;
+				uio->uio_resid = 0;
+				return (0);
+			}
+
 			/* Search for special characters for post processing. */
 			if (CMP_FLAG(o, OPOST)) {
 				plen = ttydisc_findchar(obstart, oblen);
@@ -629,6 +642,9 @@ static int
 ttydisc_echo_force(struct tty *tp, char c, int quote)
 {
 
+	if (CMP_FLAG(l, FLUSHO))
+		return 0;
+
 	if (CMP_FLAG(o, OPOST) && CTL_ECHO(c, quote)) {
 		/*
 		 * Only perform postprocessing when OPOST is turned on
@@ -879,8 +895,10 @@ ttydisc_rint(struct tty *tp, char c, int flags)
 	}
 
 	/* Allow any character to perform a wakeup. */
-	if (CMP_FLAG(i, IXANY))
+	if (CMP_FLAG(i, IXANY)) {
 		tp->t_flags &= ~TF_STOPPED;
+		tp->t_termios.c_lflag &= ~FLUSHO;
+	}
 
 	/* Remove the top bit. */
 	if (CMP_FLAG(i, ISTRIP))
@@ -906,6 +924,18 @@ ttydisc_rint(struct tty *tp, char c, int flags)
 			tp->t_flags |= TF_LITERAL;
 			return (0);
 		}
+		/* Discard processing */
+		if (CMP_CC(VDISCARD, c)) {
+			if (CMP_FLAG(l, FLUSHO)) {
+				tp->t_termios.c_lflag &= ~FLUSHO;
+			} else {
+				tty_flush(tp, FWRITE);
+				ttydisc_echo(tp, c, 0);
+				if (tp->t_inq.ti_end > 0)
+					ttydisc_reprint(tp);
+				tp->t_termios.c_lflag |= FLUSHO;
+			}
+		}
 	}
 
 	/*