Commit 0e7d56e3 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Len Brown
Browse files

Suspend: Testing facility (rev. 2) 



Introduce sysfs attribute /sys/power/pm_test allowing one to test the suspend
core code.  Namely, writing one of the strings:

freezer
devices
platform
processors
core

to this file causes the suspend code to work in one of the test modes defined as
follows:

freezer
- test the freezing of processes

devices
- test the freezing of processes and suspending of devices

platform
- test the freezing of processes, suspending of devices and platform global
  control methods(*)

processors
- test the freezing of processes, suspending of devices, platform global
  control methods and the disabling of nonboot CPUs

core
- test the freezing of processes, suspending of devices, platform global
  control methods, the disabling of nonboot CPUs and suspending of
  platform/system devices

(*) These are ACPI global control methods on ACPI systems

Then, if a suspend is started by normal means, the suspend core will perform
its normal operations up to the point indicated by given test level.  Next, it
will wait for 5 seconds and carry out the resume operations needed to transition
the system back to the fully functional state.

Writing "none" to /sys/power/pm_test turns the testing off.

When open for reading, /sys/power/pm_test contains a space-separated list of all
available tests (including "none" that represents the normal functionality) in
which the current test level is indicated by square brackets.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent c3e94d89

kernel/power/main.c

+99 −9
Original line number Diff line number Diff line
@@ -31,6 +31,79 @@ DEFINE_MUTEX(pm_mutex); 
unsigned int pm_flags;

EXPORT_SYMBOL(pm_flags);



#ifdef CONFIG_PM_DEBUG

int pm_test_level = TEST_NONE;



static int suspend_test(int level)

{

	if (pm_test_level == level) {

		printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");

		mdelay(5000);

		return 1;

	}

	return 0;

}



static const char * const pm_tests[__TEST_AFTER_LAST] = {

	[TEST_NONE] = "none",

	[TEST_CORE] = "core",

	[TEST_CPUS] = "processors",

	[TEST_PLATFORM] = "platform",

	[TEST_DEVICES] = "devices",

	[TEST_FREEZER] = "freezer",

};



static ssize_t pm_test_show(struct kset *kset, char *buf)

{

	char *s = buf;

	int level;



	for (level = TEST_FIRST; level <= TEST_MAX; level++)

		if (pm_tests[level]) {

			if (level == pm_test_level)

				s += sprintf(s, "[%s] ", pm_tests[level]);

			else

				s += sprintf(s, "%s ", pm_tests[level]);

		}



	if (s != buf)

		/* convert the last space to a newline */

		*(s-1) = '\n';



	return (s - buf);

}



static ssize_t pm_test_store(struct kset *kset, const char *buf, size_t n)

{

	const char * const *s;

	int level;

	char *p;

	int len;

	int error = -EINVAL;



	p = memchr(buf, '\n', n);

	len = p ? p - buf : n;



	mutex_lock(&pm_mutex);



	level = TEST_FIRST;

	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)

		if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {

			pm_test_level = level;

			error = 0;

			break;

		}



	mutex_unlock(&pm_mutex);



	return error ? error : n;

}



power_attr(pm_test);

#else /* !CONFIG_PM_DEBUG */

static inline int suspend_test(int level) { return 0; }

#endif /* !CONFIG_PM_DEBUG */



#ifdef CONFIG_SUSPEND



/* This is just an arbitrary number */
@@ -136,7 +209,10 @@ static int suspend_enter(suspend_state_t state) 
		printk(KERN_ERR "Some devices failed to power down\n");

		goto Done;

	}



	if (!suspend_test(TEST_CORE))

		error = suspend_ops->enter(state);



	device_power_up();

 Done:

	arch_suspend_enable_irqs();
@@ -167,16 +243,25 @@ int suspend_devices_and_enter(suspend_state_t state) 
		printk(KERN_ERR "Some devices failed to suspend\n");

		goto Resume_console;

	}



	if (suspend_test(TEST_DEVICES))

		goto Resume_devices;



	if (suspend_ops->prepare) {

		error = suspend_ops->prepare();

		if (error)

			goto Resume_devices;

	}



	if (suspend_test(TEST_PLATFORM))

		goto Finish;



	error = disable_nonboot_cpus();

	if (!error)

	if (!error && !suspend_test(TEST_CPUS))

		suspend_enter(state);



	enable_nonboot_cpus();

 Finish:

	if (suspend_ops->finish)

		suspend_ops->finish();

 Resume_devices:
@@ -243,12 +328,17 @@ static int enter_state(suspend_state_t state) 
	printk("done.\n");



	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);

	if ((error = suspend_prepare()))

	error = suspend_prepare();

	if (error)

		goto Unlock;



	if (suspend_test(TEST_FREEZER))

		goto Finish;



	pr_debug("PM: Entering %s sleep\n", pm_states[state]);

	error = suspend_devices_and_enter(state);



 Finish:

	pr_debug("PM: Finishing wakeup.\n");

	suspend_finish();

 Unlock:
@@ -369,18 +459,18 @@ pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, 
}



power_attr(pm_trace);

#endif /* CONFIG_PM_TRACE */



static struct attribute * g[] = {

	&state_attr.attr,

#ifdef CONFIG_PM_TRACE

	&pm_trace_attr.attr,

#endif

#ifdef CONFIG_PM_DEBUG

	&pm_test_attr.attr,

#endif

	NULL,

};

#else

static struct attribute * g[] = {

	&state_attr.attr,

	NULL,

};

#endif /* CONFIG_PM_TRACE */



static struct attribute_group attr_group = {

	.attrs = g,

kernel/power/power.h

+18 −0
Original line number Diff line number Diff line
@@ -188,3 +188,21 @@ int restore_highmem(void); 
static inline unsigned int count_highmem_pages(void) { return 0; }

static inline int restore_highmem(void) { return 0; }

#endif



/*

 * Suspend test levels

 */

enum {

	/* keep first */

	TEST_NONE,

	TEST_CORE,

	TEST_CPUS,

	TEST_PLATFORM,

	TEST_DEVICES,

	TEST_FREEZER,

	/* keep last */

	__TEST_AFTER_LAST

};



#define TEST_FIRST	TEST_NONE

#define TEST_MAX	(__TEST_AFTER_LAST - 1)

CRA Git | Maintained and supported by SUSTech CRA and CCSE