serial: fix enable_irq_wake/disable_irq_wake imbalance in serial_core.c

From: Arjan van de Ven <[email protected]>
Subject: [PATCH] serial: fix enable_irq_wake/disable_irq_wake imbalance in serial_core.c

enable_irq_wake() and disable_irq_wake() need to be balanced. However, serial_core.c calls these for different conditions during the suspend and resume functions...

This is causing a regular WARN_ON() as found at
http://www.kerneloops.org/search.php?search=set_irq_wake

This patch makes the conditions for triggering the _wake enable/disable sequence identical.

Signed-off-by Arjan van de Ven <[email protected]>

---
 drivers/serial/serial_core.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

drivers/serial/serial_core.c +2 -0

index eab0327..4df9ee1 100644
@@ -2054,6 +2054,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
 int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
 {
 	struct uart_state *state = drv->state + port->line;
+	struct device *tty_dev;
+	struct uart_match match = {port, drv};
 
 	mutex_lock(&state->mutex);
 

drivers/serial/serial_core.c int uart_resume_port(struct uart_driver *drv, struct uart_port *port) · line 2072

Quoted 8 lines

drivers/serial/serial_core.c +2 -1

 	}
 
-	if (!port->suspended) {
+	tty_dev = device_find_child(port->dev, &match, serial_match_port);
+	if (!port->suspended && device_may_wakeup(tty_dev)) {
 		disable_irq_wake(port->irq);
 		mutex_unlock(&state->mutex);
 		return 0;

erp, is that the easiest way of going from a uart_driver* to a device*? Doing a lookup each time is a bit unusual.