fix SERIAL_8250_DETECT_IRQ

1059-serial-8250_port-properly-handle-runtime-PM-in-IRQ.patch

@@ -0,0 +1,49 @@
+From 07f1a49b166b7e3d03de191f80a94fdd88a696d4 Mon Sep 17 00:00:00 2001
+From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+Date: Mon, 12 Sep 2016 13:55:22 +0300
+Subject: [PATCH 1059/1676] serial: 8250_port: properly handle runtime PM in
+ IRQ
+
+We can't and basically don't need to call runtime PM in IRQ handler. If IRQ is
+ours, device must be powered on. Otherwise check if the device is powered off
+and return immediately.
+
+Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+---
+ drivers/tty/serial/8250/8250_port.c | 16 +++++++++-------
+ 1 file changed, 9 insertions(+), 7 deletions(-)
+
+diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
+index 59b61d8..545411e 100644
+--- a/drivers/tty/serial/8250/8250_port.c
++++ b/drivers/tty/serial/8250/8250_port.c
+@@ -1889,17 +1889,19 @@ EXPORT_SYMBOL_GPL(serial8250_handle_irq);
+ 
+ static int serial8250_default_handle_irq(struct uart_port *port)
+ {
+-	struct uart_8250_port *up = up_to_u8250p(port);
+ 	unsigned int iir;
+-	int ret;
+ 
+-	serial8250_rpm_get(up);
++	/*
++	 * The IRQ might be shared with other peripherals so we must first
++	 * check that are we RPM suspended or not. If we are we assume that
++	 * the IRQ was not for us (we shouldn't be RPM suspended when the
++	 * interrupt is enabled).
++	 */
++	if (pm_runtime_suspended(port->dev))
++		return 0;
+ 
+ 	iir = serial_port_in(port, UART_IIR);
+-	ret = serial8250_handle_irq(port, iir);
+-
+-	serial8250_rpm_put(up);
+-	return ret;
++	return serial8250_handle_irq(port, iir);
+ }
+ 
+ /*
+-- 
+2.7.4
+