Commit af8db150 authored Nov 15, 2011 by Peter Chen Committed by Rafael J. Wysocki Nov 15, 2011

PM / driver core: disable device's runtime PM during shutdown



There may be an issue when the user issue "reboot/shutdown" command, then
the device has shut down its hardware, after that, this runtime-pm featured
device's driver will probably be scheduled to do its suspend routine,
and at its suspend routine, it may access hardware, but the device has
already shutdown physically, then the system hang may be occurred.

I ran out this issue using an auto-suspend supported USB devices, like
3G modem, keyboard. The usb runtime suspend routine may be scheduled
after the usb controller has been shut down, and the usb runtime suspend
routine will try to suspend its roothub(controller), it will access
register, then the system hang occurs as the controller is shutdown.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: stable@kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

parent 6c81f905

drivers/base/core.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include <linux/kallsyms.h>
		#include <linux/mutex.h>
		#include <linux/async.h>
		#include <linux/pm_runtime.h>

		#include "base.h"
		#include "power/power.h"
		@@ -1742,6 +1743,8 @@ void device_shutdown(void)
		*/
		list_del_init(&dev->kobj.entry);
		spin_unlock(&devices_kset->list_lock);
		/* Disable all device's runtime power management */
		pm_runtime_disable(dev);

		if (dev->bus && dev->bus->shutdown) {
		dev_dbg(dev, "shutdown\n");

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