On Wed, Aug 20, 2014 at 11:23:21AM +0200, Frans Klaver wrote:

Hi,

On Fri, Aug 15, 2014 at 07:42:31PM +0200, Sebastian Andrzej Siewior wrote:

quoted

--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c

@@ -1899,12 +1984,22 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
 
 static int serial8250_get_poll_char(struct uart_port *port)
 {
-	unsigned char lsr = serial_port_in(port, UART_LSR);
+	unsigned char lsr;
+	int status;
+
+	serial8250_rpm_get(up);

or up won't be defined below. You probably need 

Obviously I meant to say that 'up' won't be defined here.

+	struct uart_8250_port *up = up_to_u8250p(port);
somewhere in there.

quoted

-	if (!(lsr & UART_LSR_DR))
-		return NO_POLL_CHAR;
+	lsr = serial_port_in(port, UART_LSR);
 
-	return serial_port_in(port, UART_RX);
+	if (!(lsr & UART_LSR_DR)) {
+		status = NO_POLL_CHAR;
+		goto out;
+	}
+
+	status = serial_port_in(port, UART_RX);
+out:
+	serial8250_rpm_put(up);
+	return status;
 }

Cheers,
Frans