diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 71ef0d4e5423a..2294d5b633b5b 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -233,6 +233,7 @@ struct gsm_mux {
 	int initiator;			/* Did we initiate connection */
 	bool dead;			/* Has the mux been shut down */
 	struct gsm_dlci *dlci[NUM_DLCI];
+	int old_c_iflag;		/* termios c_iflag value before attach */
 	bool constipated;		/* Asked by remote to shut up */
 
 	spinlock_t tx_lock;
@@ -1959,6 +1960,16 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
 
 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
 {
+	/* handle XON/XOFF */
+	if ((c & ISO_IEC_646_MASK) == XON) {
+		gsm->constipated = true;
+		return;
+	} else if ((c & ISO_IEC_646_MASK) == XOFF) {
+		gsm->constipated = false;
+		/* Kick the link in case it is idling */
+		gsm_data_kick(gsm, NULL);
+		return;
+	}
 	if (c == GSM1_SOF) {
 		/* EOF is only valid in frame if we have got to the data state
 		   and received at least one byte (the FCS) */
@@ -2377,6 +2388,9 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
 	int ret, i;
 
 	gsm->tty = tty_kref_get(tty);
+	/* Turn off tty XON/XOFF handling to handle it explicitly. */
+	gsm->old_c_iflag = tty->termios.c_iflag;
+	tty->termios.c_iflag &= (IXON | IXOFF);
 	ret =  gsm_activate_mux(gsm);
 	if (ret != 0)
 		tty_kref_put(gsm->tty);
@@ -2417,6 +2431,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
 	WARN_ON(tty != gsm->tty);
 	for (i = 1; i < NUM_DLCI; i++)
 		tty_unregister_device(gsm_tty_driver, base + i);
+	/* Restore tty XON/XOFF handling. */
+	gsm->tty->termios.c_iflag = gsm->old_c_iflag;
 	tty_kref_put(gsm->tty);
 	gsm->tty = NULL;
 }