1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 6d0ce64163e5..ea41f2626458 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1868,6 +1868,7 @@ static int serial8250_startup(struct uart_port *port)
         }
 
         if (is_real_interrupt(up->port.irq)) {
+                unsigned char iir1;
                 /*
                  * Test for UARTs that do not reassert THRE when the
                  * transmitter is idle and the interrupt has already
@@ -1881,7 +1882,7 @@ static int serial8250_startup(struct uart_port *port)
                 wait_for_xmitr(up, UART_LSR_THRE);
                 serial_out_sync(up, UART_IER, UART_IER_THRI);
                 udelay(1); /* allow THRE to set */
-                serial_in(up, UART_IIR);
+                iir1 = serial_in(up, UART_IIR);
                 serial_out(up, UART_IER, 0);
                 serial_out_sync(up, UART_IER, UART_IER_THRI);
                 udelay(1); /* allow a working UART time to re-assert THRE */
@@ -1894,7 +1895,7 @@ static int serial8250_startup(struct uart_port *port)
                  * If the interrupt is not reasserted, setup a timer to
                  * kick the UART on a regular basis.
                  */
-                if (iir & UART_IIR_NO_INT) {
+                if (!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) {
                         pr_debug("ttyS%d - using backup timer\n", port->line);
                         up->timer.function = serial8250_backup_timeout;
                         up->timer.data = (unsigned long)up;