diff --git a/drivers/tty/serial/sa1100.c b/drivers/tty/serial/sa1100.c
index fc23ea19073a..ba25722a7131 100644
--- a/drivers/tty/serial/sa1100.c
+++ b/drivers/tty/serial/sa1100.c
@@ -232,7 +232,10 @@ sa1100_rx_chars(struct sa1100_port *sport)
 		status = UTSR1_TO_SM(UART_GET_UTSR1(sport)) |
 			 UTSR0_TO_SM(UART_GET_UTSR0(sport));
 	}
+
+	spin_unlock(&sport->port.lock);
 	tty_flip_buffer_push(&sport->port.state->port);
+	spin_lock(&sport->port.lock);
 }
 
 static void sa1100_tx_chars(struct sa1100_port *sport)