diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 271efa7ae793..56a3466acfc6 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -425,6 +425,27 @@ static int gsm_read_ea(unsigned int *val, u8 c)
 	return c & EA;
 }
 
+/**
+ *	gsm_read_ea_val	-	read a value until EA
+ *	@val: variable holding value
+ *	@data: buffer of data
+ *	@dlen: length of data
+ *
+ *	Processes an EA value. Updates the passed variable and
+ *	returns the processed data length.
+ */
+static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
+{
+	unsigned int len = 0;
+
+	for (; dlen > 0; dlen--) {
+		len++;
+		if (gsm_read_ea(val, *data++))
+			break;
+	}
+	return len;
+}
+
 /**
  *	gsm_encode_modem	-	encode modem data bits
  *	@dlci: DLCI to encode from
@@ -746,6 +767,37 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
 	return m;
 }
 
+/**
+ *	gsm_is_flow_ctrl_msg	-	checks if flow control message
+ *	@msg: message to check
+ *
+ *	Returns true if the given message is a flow control command of the
+ *	control channel. False is returned in any other case.
+ */
+static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
+{
+	unsigned int cmd;
+
+	if (msg->addr > 0)
+		return false;
+
+	switch (msg->ctrl & ~PF) {
+	case UI:
+	case UIH:
+		cmd = 0;
+		if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
+			break;
+		switch (cmd & ~PF) {
+		case CMD_FCOFF:
+		case CMD_FCON:
+			return true;
+		}
+		break;
+	}
+
+	return false;
+}
+
 /**
  *	gsm_data_kick		-	poke the queue
  *	@gsm: GSM Mux
@@ -765,7 +817,7 @@ static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
 	int len;
 
 	list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
-		if (gsm->constipated && msg->addr)
+		if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
 			continue;
 		if (gsm->encoding != 0) {
 			gsm->txframe[0] = GSM1_SOF;