1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index fbf6c5ad222f..a0e2f9d63b9d 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1050,6 +1050,15 @@ static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
         return ret;
 }
 
+static void uart_enable_ms(struct uart_port *uport)
+{
+        /*
+         * Force modem status interrupts on
+         */
+        if (uport->ops->enable_ms)
+                uport->ops->enable_ms(uport);
+}
+
 /*
  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
  * - mask passed in arg for lines of interest
@@ -1073,11 +1082,7 @@ uart_wait_modem_status(struct uart_state *state, unsigned long arg)
          */
         spin_lock_irq(&uport->lock);
         memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
-
-        /*
-         * Force modem status interrupts on
-         */
-        uport->ops->enable_ms(uport);
+        uart_enable_ms(uport);
         spin_unlock_irq(&uport->lock);
 
         add_wait_queue(&port->delta_msr_wait, &wait);
@@ -1508,7 +1513,7 @@ static int uart_carrier_raised(struct tty_port *port)
         struct uart_port *uport = state->uart_port;
         int mctrl;
         spin_lock_irq(&uport->lock);
-        uport->ops->enable_ms(uport);
+        uart_enable_ms(uport);
         mctrl = uport->ops->get_mctrl(uport);
         spin_unlock_irq(&uport->lock);
         if (mctrl & TIOCM_CAR)