1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index ce948b66bbd4..27f34a9f9cb7 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1874,7 +1874,9 @@ static int serial8250_startup(struct uart_port *port)
                  * the interrupt is enabled.  Delays are necessary to
                  * allow register changes to become visible.
                  */
-                spin_lock_irqsave(&up->port.lock, flags);
+                spin_lock(&up->port.lock);
+                if (up->port.flags & UPF_SHARE_IRQ)
+                        disable_irq_nosync(up->port.irq);
 
                 wait_for_xmitr(up, UART_LSR_THRE);
                 serial_out_sync(up, UART_IER, UART_IER_THRI);
@@ -1886,7 +1888,9 @@ static int serial8250_startup(struct uart_port *port)
                 iir = serial_in(up, UART_IIR);
                 serial_out(up, UART_IER, 0);
 
-                spin_unlock_irqrestore(&up->port.lock, flags);
+                if (up->port.flags & UPF_SHARE_IRQ)
+                        enable_irq(up->port.irq);
+                spin_unlock(&up->port.lock);
 
                 /*
                  * If the interrupt is not reasserted, setup a timer to