Commit 0e06b4a8 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM: Add a switch for disabling/enabling asynchronous suspend/resume 



Add sysfs attribute /sys/power/pm_async allowing the user space to
disable/enable asynchronous suspend/resume of devices.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 5af84b82

Documentation/ABI/testing/sysfs-power

+13 −0
Original line number Diff line number Diff line
@@ -101,3 +101,16 @@ Description: 


		CAUTION: Using it will cause your machine's real-time (CMOS)

		clock to be set to a random invalid time after a resume.



What:		/sys/power/pm_async

Date:		January 2009

Contact:	Rafael J. Wysocki <rjw@sisk.pl>

Description:

		The /sys/power/pm_async file controls the switch allowing the

		user space to enable or disable asynchronous suspend and resume

		of devices.  If enabled, this feature will cause some device

		drivers' suspend and resume callbacks to be executed in parallel

		with each other and with the main suspend thread.  It is enabled

		if this file contains "1", which is the default.  It may be

		disabled by writing "0" to this file, in which case all devices

		will be suspended and resumed synchronously.

drivers/base/power/main.c

+4 −3
Original line number Diff line number Diff line
@@ -201,7 +201,7 @@ static void dpm_wait(struct device *dev, bool async) 
	if (!dev)

		return;



	if (async || dev->power.async_suspend)

	if (async || (pm_async_enabled && dev->power.async_suspend))

		wait_for_completion(&dev->power.completion);

}
@@ -563,7 +563,8 @@ static int device_resume(struct device *dev) 
{

	INIT_COMPLETION(dev->power.completion);



	if (dev->power.async_suspend && !pm_trace_is_enabled()) {

	if (pm_async_enabled && dev->power.async_suspend

	    && !pm_trace_is_enabled()) {

		get_device(dev);

		async_schedule(async_resume, dev);

		return 0;
@@ -867,7 +868,7 @@ static int device_suspend(struct device *dev) 
{

	INIT_COMPLETION(dev->power.completion);



	if (dev->power.async_suspend) {

	if (pm_async_enabled && dev->power.async_suspend) {

		get_device(dev);

		async_schedule(async_suspend, dev);

		return 0;

drivers/base/power/power.h

+3 −3
Original line number Diff line number Diff line
@@ -12,10 +12,10 @@ static inline void pm_runtime_remove(struct device *dev) {} 


#ifdef CONFIG_PM_SLEEP



/*

 * main.c

 */

/* kernel/power/main.c */

extern int pm_async_enabled;



/* drivers/base/power/main.c */

extern struct list_head dpm_list;	/* The active device list */



static inline struct device *to_device(struct list_head *entry)

kernel/power/main.c

+30 −1
Original line number Diff line number Diff line
@@ -44,6 +44,32 @@ int pm_notifier_call_chain(unsigned long val) 
			== NOTIFY_BAD) ? -EINVAL : 0;

}



/* If set, devices may be suspended and resumed asynchronously. */

int pm_async_enabled = 1;



static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,

			     char *buf)

{

	return sprintf(buf, "%d\n", pm_async_enabled);

}



static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,

			      const char *buf, size_t n)

{

	unsigned long val;



	if (strict_strtoul(buf, 10, &val))

		return -EINVAL;



	if (val > 1)

		return -EINVAL;



	pm_async_enabled = val;

	return n;

}



power_attr(pm_async);



#ifdef CONFIG_PM_DEBUG

int pm_test_level = TEST_NONE;
@@ -208,8 +234,11 @@ static struct attribute * g[] = { 
#ifdef CONFIG_PM_TRACE

	&pm_trace_attr.attr,

#endif

#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG)

#ifdef CONFIG_PM_SLEEP

	&pm_async_attr.attr,

#ifdef CONFIG_PM_DEBUG

	&pm_test_attr.attr,

#endif

#endif

	NULL,

};