text: /*
   * kernel/power/main.c - PM subsystem core functionality.
   *
   * Copyright (c) 2003 Patrick Mochel
   * Copyright (c) 2003 Open Source Development Lab
   *
   * This file is released under the GPLv2
   *
   */
  
  #include <linux/export.h>
  #include <linux/kobject.h>
  #include <linux/string.h>
  #include <linux/pm-trace.h>
  #include <linux/workqueue.h>
  #include <linux/debugfs.h>
  #include <linux/seq_file.h>
  #include <linux/suspend.h>
  
  #include "power.h"
  
  #ifdef CONFIG_PM_SLEEP
  
  void lock_system_sleep(void)
  {
  	current->flags |= PF_FREEZER_SKIP;
  	mutex_lock(&system_transition_mutex);
  }
  EXPORT_SYMBOL_GPL(lock_system_sleep);
  
  void unlock_system_sleep(void)
  {
  	/*
  	 * Don't use freezer_count() because we don't want the call to
  	 * try_to_freeze() here.
  	 *
  	 * Reason:
  	 * Fundamentally, we just don't need it, because freezing condition
  	 * doesn't come into effect until we release the
  	 * system_transition_mutex lock, since the freezer always works with
  	 * system_transition_mutex held.
  	 *
  	 * More importantly, in the case of hibernation,
  	 * unlock_system_sleep() gets called in snapshot_read() and
  	 * snapshot_write() when the freezing condition is still in effect.
  	 * Which means, if we use try_to_freeze() here, it would make them
  	 * enter the refrigerator, thus causing hibernation to lockup.
  	 */
  	current->flags &= ~PF_FREEZER_SKIP;
  	mutex_unlock(&system_transition_mutex);
  }
  EXPORT_SYMBOL_GPL(unlock_system_sleep);
  
  /* Routines for PM-transition notifications */
  
  static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  
  int register_pm_notifier(struct notifier_block *nb)
  {
  	return blocking_notifier_chain_register(&pm_chain_head, nb);
  }
  EXPORT_SYMBOL_GPL(register_pm_notifier);
  
  int unregister_pm_notifier(struct notifier_block *nb)
  {
  	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
  }
  EXPORT_SYMBOL_GPL(unregister_pm_notifier);
  
  int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
  {
  	int ret;
  
  	ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
  						nr_to_call, nr_calls);
  
  	return notifier_to_errno(ret);
  }
  int pm_notifier_call_chain(unsigned long val)
  {
  	return __pm_notifier_call_chain(val, -1, NULL);
  }
  
  /* 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 (kstrtoul(buf, 10, &val))
  		return -EINVAL;
  
  	if (val > 1)
  		return -EINVAL;
  
  	pm_async_enabled = val;
  	return n;
  }
  
  power_attr(pm_async);
  
  #ifdef CONFIG_SUSPEND
  static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
  			      char *buf)
  {
  	char *s = buf;
  	suspend_state_t i;
  
  	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
  		if (mem_sleep_states[i]) {
  			const char *label = mem_sleep_states[i];
  
  			if (mem_sleep_current == i)
  				s += sprintf(s, "[%s] ", label);
  			else
  				s += sprintf(s, "%s ", label);
  		}
  
  	/* Convert the last space to a newline if needed. */
  	if (s != buf)
  		*(s-1) = '\n';
  
  	return (s - buf);
  }
  
  static suspend_state_t decode_suspend_state(const char *buf, size_t n)
  {
  	suspend_state_t state;
  	char *p;
  	int len;
  
  	p = memchr(buf, '\n', n);
  	len = p ? p - buf : n;
  
  	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
  		const char *label = mem_sleep_states[state];
  
  		if (label && len == strlen(label) && !strncmp(buf, label, len))
  			return state;
  	}
  
  	return PM_SUSPEND_ON;
  }
  
  static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
  			       const char *buf, size_t n)
  {
  	suspend_state_t state;
  	int error;
  
  	error = pm_autosleep_lock();
  	if (error)
  		return error;
  
  	if (pm_autosleep_state() > PM_SUSPEND_ON) {
  		error = -EBUSY;
  		goto out;
  	}
  
  	state = decode_suspend_state(buf, n);
  	if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
  		mem_sleep_current = state;
  	else
  		error = -EINVAL;
  
   out:
  	pm_autosleep_unlock();
  	return error ? error : n;
  }
  
  power_attr(mem_sleep);
  #endif /* CONFIG_SUSPEND */
  
  #ifdef CONFIG_PM_SLEEP_DEBUG
  int pm_test_level = TEST_NONE;
  
  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 kobject *kobj, struct kobj_attribute *attr,
  				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 kobject *kobj, struct kobj_attribute *attr,
  				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;
  
  	lock_system_sleep();
  
  	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;
  		}
  
  	unlock_system_sleep();
  
  	return error ? error : n;
  }
  
  power_attr(pm_test);
  #endif /* CONFIG_PM_SLEEP_DEBUG */
  
  #ifdef CONFIG_DEBUG_FS
  static char *suspend_step_name(enum suspend_stat_step step)
  {
  	switch (step) {
  	case SUSPEND_FREEZE:
  		return "freeze";
  	case SUSPEND_PREPARE:
  		return "prepare";
  	case SUSPEND_SUSPEND:
  		return "suspend";
  	case SUSPEND_SUSPEND_NOIRQ:
  		return "suspend_noirq";
  	case SUSPEND_RESUME_NOIRQ:
  		return "resume_noirq";
  	case SUSPEND_RESUME:
  		return "resume";
  	default:
  		return "";
  	}
  }
  
  static int suspend_stats_show(struct seq_file *s, void *unused)
  {
  	int i, index, last_dev, last_errno, last_step;
  
  	last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
  	last_dev %= REC_FAILED_NUM;
  	last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
  	last_errno %= REC_FAILED_NUM;
  	last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
  	last_step %= REC_FAILED_NUM;
  	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
  			"%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
  			"success", suspend_stats.success,
  			"fail", suspend_stats.fail,
  			"failed_freeze", suspend_stats.failed_freeze,
  			"failed_prepare", suspend_stats.failed_prepare,
  			"failed_suspend", suspend_stats.failed_suspend,
  			"failed_suspend_late",
  				suspend_stats.failed_suspend_late,
  			"failed_suspend_noirq",
  				suspend_stats.failed_suspend_noirq,
  			"failed_resume", suspend_stats.failed_resume,
  			"failed_resume_early",
  				suspend_stats.failed_resume_early,
  			"failed_resume_noirq",
  				suspend_stats.failed_resume_noirq);
  	seq_printf(s,	"failures:\n  last_failed_dev:\t%-s\n",
  			suspend_stats.failed_devs[last_dev]);
  	for (i = 1; i < REC_FAILED_NUM; i++) {
  		index = last_dev + REC_FAILED_NUM - i;
  		index %= REC_FAILED_NUM;
  		seq_printf(s, "\t\t\t%-s\n",
  			suspend_stats.failed_devs[index]);
  	}
  	seq_printf(s,	"  last_failed_errno:\t%-d\n",
  			suspend_stats.errno[last_errno]);
  	for (i = 1; i < REC_FAILED_NUM; i++) {
  		index = last_errno + REC_FAILED_NUM - i;
  		index %= REC_FAILED_NUM;
  		seq_printf(s, "\t\t\t%-d\n",
  			suspend_stats.errno[index]);
  	}
  	seq_printf(s,	"  last_failed_step:\t%-s\n",
  			suspend_step_name(
  				suspend_stats.failed_steps[last_step]));
  	for (i = 1; i < REC_FAILED_NUM; i++) {
  		index = last_step + REC_FAILED_NUM - i;
  		index %= REC_FAILED_NUM;
  		seq_printf(s, "\t\t\t%-s\n",
  			suspend_step_name(
  				suspend_stats.failed_steps[index]));
  	}
  
  	return 0;
  }
  
  static int suspend_stats_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, suspend_stats_show, NULL);
  }
  
  static const struct file_operations suspend_stats_operations = {
  	.open           = suspend_stats_open,
  	.read           = seq_read,
  	.llseek         = seq_lseek,
  	.release        = single_release,
  };
  
  static int __init pm_debugfs_init(void)
  {
  	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
  			NULL, NULL, &suspend_stats_operations);
  	return 0;
  }
  
  late_initcall(pm_debugfs_init);
  #endif /* CONFIG_DEBUG_FS */
  
  #endif /* CONFIG_PM_SLEEP */
  
  #ifdef CONFIG_PM_SLEEP_DEBUG
  /*
   * pm_print_times: print time taken by devices to suspend and resume.
   *
   * show() returns whether printing of suspend and resume times is enabled.
   * store() accepts 0 or 1.  0 disables printing and 1 enables it.
   */
  bool pm_print_times_enabled;
  
  static ssize_t pm_print_times_show(struct kobject *kobj,
  				   struct kobj_attribute *attr, char *buf)
  {
  	return sprintf(buf, "%d\n", pm_print_times_enabled);
  }
  
  static ssize_t pm_print_times_store(struct kobject *kobj,
  				    struct kobj_attribute *attr,
  				    const char *buf, size_t n)
  {
  	unsigned long val;
  
  	if (kstrtoul(buf, 10, &val))
  		return -EINVAL;
  
  	if (val > 1)
  		return -EINVAL;
  
  	pm_print_times_enabled = !!val;
  	return n;
  }
  
  power_attr(pm_print_times);
  
  static inline void pm_print_times_init(void)
  {
  	pm_print_times_enabled = !!initcall_debug;
  }
  
  static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
  					struct kobj_attribute *attr,
  					char *buf)
  {
  	return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
  }
  
  power_attr_ro(pm_wakeup_irq);
  
  bool pm_debug_messages_on __read_mostly;
  
  static ssize_t pm_debug_messages_show(struct kobject *kobj,
  				      struct kobj_attribute *attr, char *buf)
  {
  	return sprintf(buf, "%d\n", pm_debug_messages_on);
  }
  
  static ssize_t pm_debug_messages_store(struct kobject *kobj,
  				       struct kobj_attribute *attr,
  				       const char *buf, size_t n)
  {
  	unsigned long val;
  
  	if (kstrtoul(buf, 10, &val))
  		return -EINVAL;
  
  	if (val > 1)
  		return -EINVAL;
  
  	pm_debug_messages_on = !!val;
  	return n;
  }
  
  power_attr(pm_debug_messages);
  
  /**
   * __pm_pr_dbg - Print a suspend debug message to the kernel log.
   * @defer: Whether or not to use printk_deferred() to print the message.
   * @fmt: Message format.
   *
   * The message will be emitted if enabled through the pm_debug_messages
   * sysfs attribute.
   */
  void __pm_pr_dbg(bool defer, const char *fmt, ...)
  {
  	struct va_format vaf;
  	va_list args;
  
  	if (!pm_debug_messages_on)
  		return;
  
  	va_start(args, fmt);
  
  	vaf.fmt = fmt;
  	vaf.va = &args;
  
  	if (defer)
  		printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
  	else
  		printk(KERN_DEBUG "PM: %pV", &vaf);
  
  	va_end(args);
  }
  
  #else /* !CONFIG_PM_SLEEP_DEBUG */
  static inline void pm_print_times_init(void) {}
  #endif /* CONFIG_PM_SLEEP_DEBUG */
  
  struct kobject *power_kobj;
  
  /**
   * state - control system sleep states.
   *
   * show() returns available sleep state labels, which may be "mem", "standby",
   * "freeze" and "disk" (hibernation).
   * See Documentation/admin-guide/pm/sleep-states.rst for a description of
   * what they mean.
   *
   * store() accepts one of those strings, translates it into the proper
   * enumerated value, and initiates a suspend transition.
   */
  static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
  			  char *buf)
  {
  	char *s = buf;
  #ifdef CONFIG_SUSPEND
  	suspend_state_t i;
  
  	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
  		if (pm_states[i])
  			s += sprintf(s,"%s ", pm_states[i]);
  
  #endif
  	if (hibernation_available())
  		s += sprintf(s, "disk ");
  	if (s != buf)
  		/* convert the last space to a newline */
  		*(s-1) = '\n';
  	return (s - buf);
  }
  
  static suspend_state_t decode_state(const char *buf, size_t n)
  {
  #ifdef CONFIG_SUSPEND
  	suspend_state_t state;
  #endif
  	char *p;
  	int len;
  
  	p = memchr(buf, '\n', n);
  	len = p ? p - buf : n;
  
  	/* Check hibernation first. */
  	if (len == 4 && !strncmp(buf, "disk", len))
  		return PM_SUSPEND_MAX;
  
  #ifdef CONFIG_SUSPEND
  	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
  		const char *label = pm_states[state];
  
  		if (label && len == strlen(label) && !strncmp(buf, label, len))
  			return state;
  	}
  #endif
  
  	return PM_SUSPEND_ON;
  }
  
  static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
  			   const char *buf, size_t n)
  {
  	suspend_state_t state;
  	int error;
  
  	error = pm_autosleep_lock();
  	if (error)
  		return error;
  
  	if (pm_autosleep_state() > PM_SUSPEND_ON) {
  		error = -EBUSY;
  		goto out;
  	}
  
  	state = decode_state(buf, n);
  	if (state < PM_SUSPEND_MAX) {
  		if (state == PM_SUSPEND_MEM)
  			state = mem_sleep_current;
  
  		error = pm_suspend(state);
  	} else if (state == PM_SUSPEND_MAX) {
  		error = hibernate();
  	} else {
  		error = -EINVAL;
  	}
  
   out:
  	pm_autosleep_unlock();
  	return error ? error : n;
  }
  
  power_attr(state);
  
  #ifdef CONFIG_PM_SLEEP
  /*
   * The 'wakeup_count' attribute, along with the functions defined in
   * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
   * handled in a non-racy way.
   *
   * If a wakeup event occurs when the system is in a sleep state, it simply is
   * woken up.  In turn, if an event that would wake the system up from a sleep
   * state occurs when it is undergoing a transition to that sleep state, the
   * transition should be aborted.  Moreover, if such an event occurs when the
   * system is in the working state, an attempt to start a transition to the
   * given sleep state should fail during certain period after the detection of
   * the event.  Using the 'state' attribute alone is not sufficient to satisfy
   * these requirements, because a wakeup event may occur exactly when 'state'
   * is being written to and may be delivered to user space right before it is
   * frozen, so the event will remain only partially processed until the system is
   * woken up by another event.  In particular, it won't cause the transition to
   * a sleep state to be aborted.
   *
   * This difficulty may be overcome if user space uses 'wakeup_count' before
   * writing to 'state'.  It first should read from 'wakeup_count' and store
   * the read value.  Then, after carrying out its own preparations for the system
   * transition to a sleep state, it should write the stored value to
   * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
   * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
   * is allowed to write to 'state', but the transition will be aborted if there
   * are any wakeup events detected after 'wakeup_count' was written to.
   */
  
  static ssize_t wakeup_count_show(struct kobject *kobj,
  				struct kobj_attribute *attr,
  				char *buf)
  {
  	unsigned int val;
  
  	return pm_get_wakeup_count(&val, true) ?
  		sprintf(buf, "%u\n", val) : -EINTR;
  }
  
  static ssize_t wakeup_count_store(struct kobject *kobj,
  				struct kobj_attribute *attr,
  				const char *buf, size_t n)
  {
  	unsigned int val;
  	int error;
  
  	error = pm_autosleep_lock();
  	if (error)
  		return error;
  
  	if (pm_autosleep_state() > PM_SUSPEND_ON) {
  		error = -EBUSY;
  		goto out;
  	}
  
  	error = -EINVAL;
  	if (sscanf(buf, "%u", &val) == 1) {
  		if (pm_save_wakeup_count(val))
  			error = n;
  		else
  			pm_print_active_wakeup_sources();
  	}
  
   out:
  	pm_autosleep_unlock();
  	return error;
  }
  
  power_attr(wakeup_count);
  
  #ifdef CONFIG_PM_AUTOSLEEP
  static ssize_t autosleep_show(struct kobject *kobj,
  			      struct kobj_attribute *attr,
  			      char *buf)
  {
  	suspend_state_t state = pm_autosleep_state();
  
  	if (state == PM_SUSPEND_ON)
  		return sprintf(buf, "off\n");
  
  #ifdef CONFIG_SUSPEND
  	if (state < PM_SUSPEND_MAX)
  		return sprintf(buf, "%s\n", pm_states[state] ?
  					pm_states[state] : "error");
  #endif
  #ifdef CONFIG_HIBERNATION
  	return sprintf(buf, "disk\n");
  #else
  	return sprintf(buf, "error");
  #endif
  }
  
  static ssize_t autosleep_store(struct kobject *kobj,
  			       struct kobj_attribute *attr,
  			       const char *buf, size_t n)
  {
  	suspend_state_t state = decode_state(buf, n);
  	int error;
  
  	if (state == PM_SUSPEND_ON
  	    && strcmp(buf, "off") && strcmp(buf, "off\n"))
  		return -EINVAL;
  
  	if (state == PM_SUSPEND_MEM)
  		state = mem_sleep_current;
  
  	error = pm_autosleep_set_state(state);
  	return error ? error : n;
  }
  
  power_attr(autosleep);
  #endif /* CONFIG_PM_AUTOSLEEP */
  
  #ifdef CONFIG_PM_WAKELOCKS
  static ssize_t wake_lock_show(struct kobject *kobj,
  			      struct kobj_attribute *attr,
  			      char *buf)
  {
  	return pm_show_wakelocks(buf, true);
  }
  
  static ssize_t wake_lock_store(struct kobject *kobj,
  			       struct kobj_attribute *attr,
  			       const char *buf, size_t n)
  {
  	int error = pm_wake_lock(buf);
  	return error ? error : n;
  }
  
  power_attr(wake_lock);
  
  static ssize_t wake_unlock_show(struct kobject *kobj,
  				struct kobj_attribute *attr,
  				char *buf)
  {
  	return pm_show_wakelocks(buf, false);
  }
  
  static ssize_t wake_unlock_store(struct kobject *kobj,
  				 struct kobj_attribute *attr,
  				 const char *buf, size_t n)
  {
  	int error = pm_wake_unlock(buf);
  	return error ? error : n;
  }
  
  power_attr(wake_unlock);
  
  #endif /* CONFIG_PM_WAKELOCKS */
  #endif /* CONFIG_PM_SLEEP */
  
  #ifdef CONFIG_PM_TRACE
  int pm_trace_enabled;
  
  static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
  			     char *buf)
  {
  	return sprintf(buf, "%d\n", pm_trace_enabled);
  }
  
  static ssize_t
  pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
  	       const char *buf, size_t n)
  {
  	int val;
  
  	if (sscanf(buf, "%d", &val) == 1) {
  		pm_trace_enabled = !!val;
  		if (pm_trace_enabled) {
  			pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
  				"PM: Correct system time has to be restored manually after resume.\n");
  		}
  		return n;
  	}
  	return -EINVAL;
  }
  
  power_attr(pm_trace);
  
  static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
  				       struct kobj_attribute *attr,
  				       char *buf)
  {
  	return show_trace_dev_match(buf, PAGE_SIZE);
  }
  
  power_attr_ro(pm_trace_dev_match);
  
  #endif /* CONFIG_PM_TRACE */
  
  #ifdef CONFIG_FREEZER
  static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
  				      struct kobj_attribute *attr, char *buf)
  {
  	return sprintf(buf, "%u\n", freeze_timeout_msecs);
  }
  
  static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
  				       struct kobj_attribute *attr,
  				       const char *buf, size_t n)
  {
  	unsigned long val;
  
  	if (kstrtoul(buf, 10, &val))
  		return -EINVAL;
  
  	freeze_timeout_msecs = val;
  	return n;
  }
  
  power_attr(pm_freeze_timeout);
  
  #endif	/* CONFIG_FREEZER*/
  
  static struct attribute * g[] = {
  	&state_attr.attr,
  #ifdef CONFIG_PM_TRACE
  	&pm_trace_attr.attr,
  	&pm_trace_dev_match_attr.attr,
  #endif
  #ifdef CONFIG_PM_SLEEP
  	&pm_async_attr.attr,
  	&wakeup_count_attr.attr,
  #ifdef CONFIG_SUSPEND
  	&mem_sleep_attr.attr,
  #endif
  #ifdef CONFIG_PM_AUTOSLEEP
  	&autosleep_attr.attr,
  #endif
  #ifdef CONFIG_PM_WAKELOCKS
  	&wake_lock_attr.attr,
  	&wake_unlock_attr.attr,
  #endif
  #ifdef CONFIG_PM_SLEEP_DEBUG
  	&pm_test_attr.attr,
  	&pm_print_times_attr.attr,
  	&pm_wakeup_irq_attr.attr,
  	&pm_debug_messages_attr.attr,
  #endif
  #endif
  #ifdef CONFIG_FREEZER
  	&pm_freeze_timeout_attr.attr,
  #endif
  	NULL,
  };
  
  static const struct attribute_group attr_group = {
  	.attrs = g,
  };
  
  struct workqueue_struct *pm_wq;
  EXPORT_SYMBOL_GPL(pm_wq);
  
  static int __init pm_start_workqueue(void)
  {
  	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
  
  	return pm_wq ? 0 : -ENOMEM;
  }
  
  static int __init pm_init(void)
  {
  	int error = pm_start_workqueue();
  	if (error)
  		return error;
  	hibernate_image_size_init();
  	hibernate_reserved_size_init();
  	pm_states_init();
  	power_kobj = kobject_create_and_add("power", NULL);
  	if (!power_kobj)
  		return -ENOMEM;
  	error = sysfs_create_group(power_kobj, &attr_group);
  	if (error)
  		return error;
  	pm_print_times_init();
  	return pm_autosleep_init();
  }
  
  core_initcall(pm_init);
  