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

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

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2010-01-23 22:25:15 +01:00
parent 5af84b8270
commit 0e06b4a891
4 changed files with 50 additions and 7 deletions
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13
Documentation/ABI/testing/sysfs-power
View File

@ -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.

7
drivers/base/power/main.c
View File

@ -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;

6
drivers/base/power/power.h
View File

@ -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)

31
kernel/power/main.c
View File

@ -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,
};