1 // SPDX-License-Identifier: GPL-2.0-only
3 * kernel/power/main.c - PM subsystem core functionality.
5 * Copyright (c) 2003 Patrick Mochel
6 * Copyright (c) 2003 Open Source Development Lab
9 #include <linux/export.h>
10 #include <linux/kobject.h>
11 #include <linux/string.h>
12 #include <linux/pm-trace.h>
13 #include <linux/workqueue.h>
14 #include <linux/debugfs.h>
15 #include <linux/seq_file.h>
16 #include <linux/suspend.h>
17 #include <linux/syscalls.h>
18 #include <linux/pm_runtime.h>
22 #ifdef CONFIG_PM_SLEEP
24 void lock_system_sleep(void)
26 current->flags |= PF_FREEZER_SKIP;
27 mutex_lock(&system_transition_mutex);
29 EXPORT_SYMBOL_GPL(lock_system_sleep);
31 void unlock_system_sleep(void)
34 * Don't use freezer_count() because we don't want the call to
35 * try_to_freeze() here.
38 * Fundamentally, we just don't need it, because freezing condition
39 * doesn't come into effect until we release the
40 * system_transition_mutex lock, since the freezer always works with
41 * system_transition_mutex held.
43 * More importantly, in the case of hibernation,
44 * unlock_system_sleep() gets called in snapshot_read() and
45 * snapshot_write() when the freezing condition is still in effect.
46 * Which means, if we use try_to_freeze() here, it would make them
47 * enter the refrigerator, thus causing hibernation to lockup.
49 current->flags &= ~PF_FREEZER_SKIP;
50 mutex_unlock(&system_transition_mutex);
52 EXPORT_SYMBOL_GPL(unlock_system_sleep);
54 void ksys_sync_helper(void)
61 elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start));
62 pr_info("Filesystems sync: %ld.%03ld seconds\n",
63 elapsed_msecs / MSEC_PER_SEC, elapsed_msecs % MSEC_PER_SEC);
65 EXPORT_SYMBOL_GPL(ksys_sync_helper);
67 /* Routines for PM-transition notifications */
69 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
71 int register_pm_notifier(struct notifier_block *nb)
73 return blocking_notifier_chain_register(&pm_chain_head, nb);
75 EXPORT_SYMBOL_GPL(register_pm_notifier);
77 int unregister_pm_notifier(struct notifier_block *nb)
79 return blocking_notifier_chain_unregister(&pm_chain_head, nb);
81 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
83 int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down)
87 ret = blocking_notifier_call_chain_robust(&pm_chain_head, val_up, val_down, NULL);
89 return notifier_to_errno(ret);
92 int pm_notifier_call_chain(unsigned long val)
94 return blocking_notifier_call_chain(&pm_chain_head, val, NULL);
97 /* If set, devices may be suspended and resumed asynchronously. */
98 int pm_async_enabled = 1;
100 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
103 return sprintf(buf, "%d\n", pm_async_enabled);
106 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
107 const char *buf, size_t n)
111 if (kstrtoul(buf, 10, &val))
117 pm_async_enabled = val;
121 power_attr(pm_async);
123 #ifdef CONFIG_SUSPEND
124 static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
130 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
131 if (mem_sleep_states[i]) {
132 const char *label = mem_sleep_states[i];
134 if (mem_sleep_current == i)
135 s += sprintf(s, "[%s] ", label);
137 s += sprintf(s, "%s ", label);
140 /* Convert the last space to a newline if needed. */
147 static suspend_state_t decode_suspend_state(const char *buf, size_t n)
149 suspend_state_t state;
153 p = memchr(buf, '\n', n);
154 len = p ? p - buf : n;
156 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
157 const char *label = mem_sleep_states[state];
159 if (label && len == strlen(label) && !strncmp(buf, label, len))
163 return PM_SUSPEND_ON;
166 static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
167 const char *buf, size_t n)
169 suspend_state_t state;
172 error = pm_autosleep_lock();
176 if (pm_autosleep_state() > PM_SUSPEND_ON) {
181 state = decode_suspend_state(buf, n);
182 if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
183 mem_sleep_current = state;
188 pm_autosleep_unlock();
189 return error ? error : n;
192 power_attr(mem_sleep);
195 * sync_on_suspend: invoke ksys_sync_helper() before suspend.
197 * show() returns whether ksys_sync_helper() is invoked before suspend.
198 * store() accepts 0 or 1. 0 disables ksys_sync_helper() and 1 enables it.
200 bool sync_on_suspend_enabled = !IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC);
202 static ssize_t sync_on_suspend_show(struct kobject *kobj,
203 struct kobj_attribute *attr, char *buf)
205 return sprintf(buf, "%d\n", sync_on_suspend_enabled);
208 static ssize_t sync_on_suspend_store(struct kobject *kobj,
209 struct kobj_attribute *attr,
210 const char *buf, size_t n)
214 if (kstrtoul(buf, 10, &val))
220 sync_on_suspend_enabled = !!val;
224 power_attr(sync_on_suspend);
225 #endif /* CONFIG_SUSPEND */
227 #ifdef CONFIG_PM_SLEEP_DEBUG
228 int pm_test_level = TEST_NONE;
230 static const char * const pm_tests[__TEST_AFTER_LAST] = {
231 [TEST_NONE] = "none",
232 [TEST_CORE] = "core",
233 [TEST_CPUS] = "processors",
234 [TEST_PLATFORM] = "platform",
235 [TEST_DEVICES] = "devices",
236 [TEST_FREEZER] = "freezer",
239 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
245 for (level = TEST_FIRST; level <= TEST_MAX; level++)
246 if (pm_tests[level]) {
247 if (level == pm_test_level)
248 s += sprintf(s, "[%s] ", pm_tests[level]);
250 s += sprintf(s, "%s ", pm_tests[level]);
254 /* convert the last space to a newline */
260 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
261 const char *buf, size_t n)
263 const char * const *s;
269 p = memchr(buf, '\n', n);
270 len = p ? p - buf : n;
275 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
276 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
277 pm_test_level = level;
282 unlock_system_sleep();
284 return error ? error : n;
288 #endif /* CONFIG_PM_SLEEP_DEBUG */
290 static char *suspend_step_name(enum suspend_stat_step step)
295 case SUSPEND_PREPARE:
297 case SUSPEND_SUSPEND:
299 case SUSPEND_SUSPEND_NOIRQ:
300 return "suspend_noirq";
301 case SUSPEND_RESUME_NOIRQ:
302 return "resume_noirq";
310 #define suspend_attr(_name) \
311 static ssize_t _name##_show(struct kobject *kobj, \
312 struct kobj_attribute *attr, char *buf) \
314 return sprintf(buf, "%d\n", suspend_stats._name); \
316 static struct kobj_attribute _name = __ATTR_RO(_name)
318 suspend_attr(success);
320 suspend_attr(failed_freeze);
321 suspend_attr(failed_prepare);
322 suspend_attr(failed_suspend);
323 suspend_attr(failed_suspend_late);
324 suspend_attr(failed_suspend_noirq);
325 suspend_attr(failed_resume);
326 suspend_attr(failed_resume_early);
327 suspend_attr(failed_resume_noirq);
329 static ssize_t last_failed_dev_show(struct kobject *kobj,
330 struct kobj_attribute *attr, char *buf)
333 char *last_failed_dev = NULL;
335 index = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
336 index %= REC_FAILED_NUM;
337 last_failed_dev = suspend_stats.failed_devs[index];
339 return sprintf(buf, "%s\n", last_failed_dev);
341 static struct kobj_attribute last_failed_dev = __ATTR_RO(last_failed_dev);
343 static ssize_t last_failed_errno_show(struct kobject *kobj,
344 struct kobj_attribute *attr, char *buf)
347 int last_failed_errno;
349 index = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
350 index %= REC_FAILED_NUM;
351 last_failed_errno = suspend_stats.errno[index];
353 return sprintf(buf, "%d\n", last_failed_errno);
355 static struct kobj_attribute last_failed_errno = __ATTR_RO(last_failed_errno);
357 static ssize_t last_failed_step_show(struct kobject *kobj,
358 struct kobj_attribute *attr, char *buf)
361 enum suspend_stat_step step;
362 char *last_failed_step = NULL;
364 index = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
365 index %= REC_FAILED_NUM;
366 step = suspend_stats.failed_steps[index];
367 last_failed_step = suspend_step_name(step);
369 return sprintf(buf, "%s\n", last_failed_step);
371 static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
373 static struct attribute *suspend_attrs[] = {
377 &failed_prepare.attr,
378 &failed_suspend.attr,
379 &failed_suspend_late.attr,
380 &failed_suspend_noirq.attr,
382 &failed_resume_early.attr,
383 &failed_resume_noirq.attr,
384 &last_failed_dev.attr,
385 &last_failed_errno.attr,
386 &last_failed_step.attr,
390 static const struct attribute_group suspend_attr_group = {
391 .name = "suspend_stats",
392 .attrs = suspend_attrs,
395 #ifdef CONFIG_DEBUG_FS
396 static int suspend_stats_show(struct seq_file *s, void *unused)
398 int i, index, last_dev, last_errno, last_step;
400 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
401 last_dev %= REC_FAILED_NUM;
402 last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
403 last_errno %= REC_FAILED_NUM;
404 last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
405 last_step %= REC_FAILED_NUM;
406 seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
407 "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
408 "success", suspend_stats.success,
409 "fail", suspend_stats.fail,
410 "failed_freeze", suspend_stats.failed_freeze,
411 "failed_prepare", suspend_stats.failed_prepare,
412 "failed_suspend", suspend_stats.failed_suspend,
413 "failed_suspend_late",
414 suspend_stats.failed_suspend_late,
415 "failed_suspend_noirq",
416 suspend_stats.failed_suspend_noirq,
417 "failed_resume", suspend_stats.failed_resume,
418 "failed_resume_early",
419 suspend_stats.failed_resume_early,
420 "failed_resume_noirq",
421 suspend_stats.failed_resume_noirq);
422 seq_printf(s, "failures:\n last_failed_dev:\t%-s\n",
423 suspend_stats.failed_devs[last_dev]);
424 for (i = 1; i < REC_FAILED_NUM; i++) {
425 index = last_dev + REC_FAILED_NUM - i;
426 index %= REC_FAILED_NUM;
427 seq_printf(s, "\t\t\t%-s\n",
428 suspend_stats.failed_devs[index]);
430 seq_printf(s, " last_failed_errno:\t%-d\n",
431 suspend_stats.errno[last_errno]);
432 for (i = 1; i < REC_FAILED_NUM; i++) {
433 index = last_errno + REC_FAILED_NUM - i;
434 index %= REC_FAILED_NUM;
435 seq_printf(s, "\t\t\t%-d\n",
436 suspend_stats.errno[index]);
438 seq_printf(s, " last_failed_step:\t%-s\n",
440 suspend_stats.failed_steps[last_step]));
441 for (i = 1; i < REC_FAILED_NUM; i++) {
442 index = last_step + REC_FAILED_NUM - i;
443 index %= REC_FAILED_NUM;
444 seq_printf(s, "\t\t\t%-s\n",
446 suspend_stats.failed_steps[index]));
451 DEFINE_SHOW_ATTRIBUTE(suspend_stats);
453 static int __init pm_debugfs_init(void)
455 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
456 NULL, NULL, &suspend_stats_fops);
460 late_initcall(pm_debugfs_init);
461 #endif /* CONFIG_DEBUG_FS */
463 #endif /* CONFIG_PM_SLEEP */
465 #ifdef CONFIG_PM_SLEEP_DEBUG
467 * pm_print_times: print time taken by devices to suspend and resume.
469 * show() returns whether printing of suspend and resume times is enabled.
470 * store() accepts 0 or 1. 0 disables printing and 1 enables it.
472 bool pm_print_times_enabled;
474 static ssize_t pm_print_times_show(struct kobject *kobj,
475 struct kobj_attribute *attr, char *buf)
477 return sprintf(buf, "%d\n", pm_print_times_enabled);
480 static ssize_t pm_print_times_store(struct kobject *kobj,
481 struct kobj_attribute *attr,
482 const char *buf, size_t n)
486 if (kstrtoul(buf, 10, &val))
492 pm_print_times_enabled = !!val;
496 power_attr(pm_print_times);
498 static inline void pm_print_times_init(void)
500 pm_print_times_enabled = !!initcall_debug;
503 static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
504 struct kobj_attribute *attr,
507 return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
510 power_attr_ro(pm_wakeup_irq);
512 bool pm_debug_messages_on __read_mostly;
514 static ssize_t pm_debug_messages_show(struct kobject *kobj,
515 struct kobj_attribute *attr, char *buf)
517 return sprintf(buf, "%d\n", pm_debug_messages_on);
520 static ssize_t pm_debug_messages_store(struct kobject *kobj,
521 struct kobj_attribute *attr,
522 const char *buf, size_t n)
526 if (kstrtoul(buf, 10, &val))
532 pm_debug_messages_on = !!val;
536 power_attr(pm_debug_messages);
538 static int __init pm_debug_messages_setup(char *str)
540 pm_debug_messages_on = true;
543 __setup("pm_debug_messages", pm_debug_messages_setup);
546 * __pm_pr_dbg - Print a suspend debug message to the kernel log.
547 * @defer: Whether or not to use printk_deferred() to print the message.
548 * @fmt: Message format.
550 * The message will be emitted if enabled through the pm_debug_messages
553 void __pm_pr_dbg(bool defer, const char *fmt, ...)
555 struct va_format vaf;
558 if (!pm_debug_messages_on)
567 printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
569 printk(KERN_DEBUG "PM: %pV", &vaf);
574 #else /* !CONFIG_PM_SLEEP_DEBUG */
575 static inline void pm_print_times_init(void) {}
576 #endif /* CONFIG_PM_SLEEP_DEBUG */
578 struct kobject *power_kobj;
581 * state - control system sleep states.
583 * show() returns available sleep state labels, which may be "mem", "standby",
584 * "freeze" and "disk" (hibernation).
585 * See Documentation/admin-guide/pm/sleep-states.rst for a description of
588 * store() accepts one of those strings, translates it into the proper
589 * enumerated value, and initiates a suspend transition.
591 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
595 #ifdef CONFIG_SUSPEND
598 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
600 s += sprintf(s,"%s ", pm_states[i]);
603 if (hibernation_available())
604 s += sprintf(s, "disk ");
606 /* convert the last space to a newline */
611 static suspend_state_t decode_state(const char *buf, size_t n)
613 #ifdef CONFIG_SUSPEND
614 suspend_state_t state;
619 p = memchr(buf, '\n', n);
620 len = p ? p - buf : n;
622 /* Check hibernation first. */
623 if (len == 4 && str_has_prefix(buf, "disk"))
624 return PM_SUSPEND_MAX;
626 #ifdef CONFIG_SUSPEND
627 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
628 const char *label = pm_states[state];
630 if (label && len == strlen(label) && !strncmp(buf, label, len))
635 return PM_SUSPEND_ON;
638 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
639 const char *buf, size_t n)
641 suspend_state_t state;
644 error = pm_autosleep_lock();
648 if (pm_autosleep_state() > PM_SUSPEND_ON) {
653 state = decode_state(buf, n);
654 if (state < PM_SUSPEND_MAX) {
655 if (state == PM_SUSPEND_MEM)
656 state = mem_sleep_current;
658 error = pm_suspend(state);
659 } else if (state == PM_SUSPEND_MAX) {
666 pm_autosleep_unlock();
667 return error ? error : n;
672 #ifdef CONFIG_PM_SLEEP
674 * The 'wakeup_count' attribute, along with the functions defined in
675 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
676 * handled in a non-racy way.
678 * If a wakeup event occurs when the system is in a sleep state, it simply is
679 * woken up. In turn, if an event that would wake the system up from a sleep
680 * state occurs when it is undergoing a transition to that sleep state, the
681 * transition should be aborted. Moreover, if such an event occurs when the
682 * system is in the working state, an attempt to start a transition to the
683 * given sleep state should fail during certain period after the detection of
684 * the event. Using the 'state' attribute alone is not sufficient to satisfy
685 * these requirements, because a wakeup event may occur exactly when 'state'
686 * is being written to and may be delivered to user space right before it is
687 * frozen, so the event will remain only partially processed until the system is
688 * woken up by another event. In particular, it won't cause the transition to
689 * a sleep state to be aborted.
691 * This difficulty may be overcome if user space uses 'wakeup_count' before
692 * writing to 'state'. It first should read from 'wakeup_count' and store
693 * the read value. Then, after carrying out its own preparations for the system
694 * transition to a sleep state, it should write the stored value to
695 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since
696 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
697 * is allowed to write to 'state', but the transition will be aborted if there
698 * are any wakeup events detected after 'wakeup_count' was written to.
701 static ssize_t wakeup_count_show(struct kobject *kobj,
702 struct kobj_attribute *attr,
707 return pm_get_wakeup_count(&val, true) ?
708 sprintf(buf, "%u\n", val) : -EINTR;
711 static ssize_t wakeup_count_store(struct kobject *kobj,
712 struct kobj_attribute *attr,
713 const char *buf, size_t n)
718 error = pm_autosleep_lock();
722 if (pm_autosleep_state() > PM_SUSPEND_ON) {
728 if (sscanf(buf, "%u", &val) == 1) {
729 if (pm_save_wakeup_count(val))
732 pm_print_active_wakeup_sources();
736 pm_autosleep_unlock();
740 power_attr(wakeup_count);
742 #ifdef CONFIG_PM_AUTOSLEEP
743 static ssize_t autosleep_show(struct kobject *kobj,
744 struct kobj_attribute *attr,
747 suspend_state_t state = pm_autosleep_state();
749 if (state == PM_SUSPEND_ON)
750 return sprintf(buf, "off\n");
752 #ifdef CONFIG_SUSPEND
753 if (state < PM_SUSPEND_MAX)
754 return sprintf(buf, "%s\n", pm_states[state] ?
755 pm_states[state] : "error");
757 #ifdef CONFIG_HIBERNATION
758 return sprintf(buf, "disk\n");
760 return sprintf(buf, "error");
764 static ssize_t autosleep_store(struct kobject *kobj,
765 struct kobj_attribute *attr,
766 const char *buf, size_t n)
768 suspend_state_t state = decode_state(buf, n);
771 if (state == PM_SUSPEND_ON
772 && strcmp(buf, "off") && strcmp(buf, "off\n"))
775 if (state == PM_SUSPEND_MEM)
776 state = mem_sleep_current;
778 error = pm_autosleep_set_state(state);
779 return error ? error : n;
782 power_attr(autosleep);
783 #endif /* CONFIG_PM_AUTOSLEEP */
785 #ifdef CONFIG_PM_WAKELOCKS
786 static ssize_t wake_lock_show(struct kobject *kobj,
787 struct kobj_attribute *attr,
790 return pm_show_wakelocks(buf, true);
793 static ssize_t wake_lock_store(struct kobject *kobj,
794 struct kobj_attribute *attr,
795 const char *buf, size_t n)
797 int error = pm_wake_lock(buf);
798 return error ? error : n;
801 power_attr(wake_lock);
803 static ssize_t wake_unlock_show(struct kobject *kobj,
804 struct kobj_attribute *attr,
807 return pm_show_wakelocks(buf, false);
810 static ssize_t wake_unlock_store(struct kobject *kobj,
811 struct kobj_attribute *attr,
812 const char *buf, size_t n)
814 int error = pm_wake_unlock(buf);
815 return error ? error : n;
818 power_attr(wake_unlock);
820 #endif /* CONFIG_PM_WAKELOCKS */
821 #endif /* CONFIG_PM_SLEEP */
823 #ifdef CONFIG_PM_TRACE
824 int pm_trace_enabled;
826 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
829 return sprintf(buf, "%d\n", pm_trace_enabled);
833 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
834 const char *buf, size_t n)
838 if (sscanf(buf, "%d", &val) == 1) {
839 pm_trace_enabled = !!val;
840 if (pm_trace_enabled) {
841 pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
842 "PM: Correct system time has to be restored manually after resume.\n");
849 power_attr(pm_trace);
851 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
852 struct kobj_attribute *attr,
855 return show_trace_dev_match(buf, PAGE_SIZE);
858 power_attr_ro(pm_trace_dev_match);
860 #endif /* CONFIG_PM_TRACE */
862 #ifdef CONFIG_FREEZER
863 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
864 struct kobj_attribute *attr, char *buf)
866 return sprintf(buf, "%u\n", freeze_timeout_msecs);
869 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
870 struct kobj_attribute *attr,
871 const char *buf, size_t n)
875 if (kstrtoul(buf, 10, &val))
878 freeze_timeout_msecs = val;
882 power_attr(pm_freeze_timeout);
884 #endif /* CONFIG_FREEZER*/
886 static struct attribute * g[] = {
888 #ifdef CONFIG_PM_TRACE
890 &pm_trace_dev_match_attr.attr,
892 #ifdef CONFIG_PM_SLEEP
894 &wakeup_count_attr.attr,
895 #ifdef CONFIG_SUSPEND
896 &mem_sleep_attr.attr,
897 &sync_on_suspend_attr.attr,
899 #ifdef CONFIG_PM_AUTOSLEEP
900 &autosleep_attr.attr,
902 #ifdef CONFIG_PM_WAKELOCKS
903 &wake_lock_attr.attr,
904 &wake_unlock_attr.attr,
906 #ifdef CONFIG_PM_SLEEP_DEBUG
908 &pm_print_times_attr.attr,
909 &pm_wakeup_irq_attr.attr,
910 &pm_debug_messages_attr.attr,
913 #ifdef CONFIG_FREEZER
914 &pm_freeze_timeout_attr.attr,
919 static const struct attribute_group attr_group = {
923 static const struct attribute_group *attr_groups[] = {
925 #ifdef CONFIG_PM_SLEEP
931 struct workqueue_struct *pm_wq;
932 EXPORT_SYMBOL_GPL(pm_wq);
934 static int __init pm_start_workqueue(void)
936 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
938 return pm_wq ? 0 : -ENOMEM;
941 static int __init pm_init(void)
943 int error = pm_start_workqueue();
946 hibernate_image_size_init();
947 hibernate_reserved_size_init();
949 power_kobj = kobject_create_and_add("power", NULL);
952 error = sysfs_create_groups(power_kobj, attr_groups);
955 pm_print_times_init();
956 return pm_autosleep_init();
959 core_initcall(pm_init);