2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
7 * This file is released under the GPLv2.
10 #include <linux/sched/mm.h>
11 #include <linux/ktime.h>
12 #include <linux/hrtimer.h>
13 #include <linux/export.h>
14 #include <linux/pm_runtime.h>
15 #include <linux/pm_wakeirq.h>
16 #include <trace/events/rpm.h>
21 typedef int (*pm_callback_t)(struct device *);
23 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
26 const struct dev_pm_ops *ops;
29 ops = &dev->pm_domain->ops;
30 else if (dev->type && dev->type->pm)
32 else if (dev->class && dev->class->pm)
34 else if (dev->bus && dev->bus->pm)
40 cb = *(pm_callback_t *)((void *)ops + cb_offset);
44 if (!cb && dev->driver && dev->driver->pm)
45 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
50 #define RPM_GET_CALLBACK(dev, callback) \
51 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
53 static int rpm_resume(struct device *dev, int rpmflags);
54 static int rpm_suspend(struct device *dev, int rpmflags);
57 * update_pm_runtime_accounting - Update the time accounting of power states
58 * @dev: Device to update the accounting for
60 * In order to be able to have time accounting of the various power states
61 * (as used by programs such as PowerTOP to show the effectiveness of runtime
62 * PM), we need to track the time spent in each state.
63 * update_pm_runtime_accounting must be called each time before the
64 * runtime_status field is updated, to account the time in the old state
67 void update_pm_runtime_accounting(struct device *dev)
69 unsigned long now = jiffies;
72 delta = now - dev->power.accounting_timestamp;
74 dev->power.accounting_timestamp = now;
76 if (dev->power.disable_depth > 0)
79 if (dev->power.runtime_status == RPM_SUSPENDED)
80 dev->power.suspended_jiffies += delta;
82 dev->power.active_jiffies += delta;
85 static void __update_runtime_status(struct device *dev, enum rpm_status status)
87 update_pm_runtime_accounting(dev);
88 dev->power.runtime_status = status;
92 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
93 * @dev: Device to handle.
95 static void pm_runtime_deactivate_timer(struct device *dev)
97 if (dev->power.timer_expires > 0) {
98 hrtimer_cancel(&dev->power.suspend_timer);
99 dev->power.timer_expires = 0;
104 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
105 * @dev: Device to handle.
107 static void pm_runtime_cancel_pending(struct device *dev)
109 pm_runtime_deactivate_timer(dev);
111 * In case there's a request pending, make sure its work function will
112 * return without doing anything.
114 dev->power.request = RPM_REQ_NONE;
118 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
119 * @dev: Device to handle.
121 * Compute the autosuspend-delay expiration time based on the device's
122 * power.last_busy time. If the delay has already expired or is disabled
123 * (negative) or the power.use_autosuspend flag isn't set, return 0.
124 * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
126 * This function may be called either with or without dev->power.lock held.
127 * Either way it can be racy, since power.last_busy may be updated at any time.
129 u64 pm_runtime_autosuspend_expiration(struct device *dev)
131 int autosuspend_delay;
132 u64 last_busy, expires = 0;
133 u64 now = ktime_get_mono_fast_ns();
135 if (!dev->power.use_autosuspend)
138 autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
139 if (autosuspend_delay < 0)
142 last_busy = READ_ONCE(dev->power.last_busy);
144 expires = last_busy + (u64)autosuspend_delay * NSEC_PER_MSEC;
146 expires = 0; /* Already expired. */
151 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
153 static int dev_memalloc_noio(struct device *dev, void *data)
155 return dev->power.memalloc_noio;
159 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
160 * @dev: Device to handle.
161 * @enable: True for setting the flag and False for clearing the flag.
163 * Set the flag for all devices in the path from the device to the
164 * root device in the device tree if @enable is true, otherwise clear
165 * the flag for devices in the path whose siblings don't set the flag.
167 * The function should only be called by block device, or network
168 * device driver for solving the deadlock problem during runtime
171 * If memory allocation with GFP_KERNEL is called inside runtime
172 * resume/suspend callback of any one of its ancestors(or the
173 * block device itself), the deadlock may be triggered inside the
174 * memory allocation since it might not complete until the block
175 * device becomes active and the involed page I/O finishes. The
176 * situation is pointed out first by Alan Stern. Network device
177 * are involved in iSCSI kind of situation.
179 * The lock of dev_hotplug_mutex is held in the function for handling
180 * hotplug race because pm_runtime_set_memalloc_noio() may be called
183 * The function should be called between device_add() and device_del()
184 * on the affected device(block/network device).
186 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
188 static DEFINE_MUTEX(dev_hotplug_mutex);
190 mutex_lock(&dev_hotplug_mutex);
194 /* hold power lock since bitfield is not SMP-safe. */
195 spin_lock_irq(&dev->power.lock);
196 enabled = dev->power.memalloc_noio;
197 dev->power.memalloc_noio = enable;
198 spin_unlock_irq(&dev->power.lock);
201 * not need to enable ancestors any more if the device
204 if (enabled && enable)
210 * clear flag of the parent device only if all the
211 * children don't set the flag because ancestor's
212 * flag was set by any one of the descendants.
214 if (!dev || (!enable &&
215 device_for_each_child(dev, NULL,
219 mutex_unlock(&dev_hotplug_mutex);
221 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
224 * rpm_check_suspend_allowed - Test whether a device may be suspended.
225 * @dev: Device to test.
227 static int rpm_check_suspend_allowed(struct device *dev)
231 if (dev->power.runtime_error)
233 else if (dev->power.disable_depth > 0)
235 else if (atomic_read(&dev->power.usage_count) > 0)
237 else if (!dev->power.ignore_children &&
238 atomic_read(&dev->power.child_count))
241 /* Pending resume requests take precedence over suspends. */
242 else if ((dev->power.deferred_resume
243 && dev->power.runtime_status == RPM_SUSPENDING)
244 || (dev->power.request_pending
245 && dev->power.request == RPM_REQ_RESUME))
247 else if (__dev_pm_qos_read_value(dev) == 0)
249 else if (dev->power.runtime_status == RPM_SUSPENDED)
255 static int rpm_get_suppliers(struct device *dev)
257 struct device_link *link;
259 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
262 if (!(link->flags & DL_FLAG_PM_RUNTIME))
265 if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND ||
269 retval = pm_runtime_get_sync(link->supplier);
270 /* Ignore suppliers with disabled runtime PM. */
271 if (retval < 0 && retval != -EACCES) {
272 pm_runtime_put_noidle(link->supplier);
275 link->rpm_active = true;
280 static void rpm_put_suppliers(struct device *dev)
282 struct device_link *link;
284 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
285 if (link->rpm_active &&
286 READ_ONCE(link->status) != DL_STATE_SUPPLIER_UNBIND) {
287 pm_runtime_put(link->supplier);
288 link->rpm_active = false;
293 * __rpm_callback - Run a given runtime PM callback for a given device.
294 * @cb: Runtime PM callback to run.
295 * @dev: Device to run the callback for.
297 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
298 __releases(&dev->power.lock) __acquires(&dev->power.lock)
301 bool use_links = dev->power.links_count > 0;
303 if (dev->power.irq_safe) {
304 spin_unlock(&dev->power.lock);
306 spin_unlock_irq(&dev->power.lock);
309 * Resume suppliers if necessary.
311 * The device's runtime PM status cannot change until this
312 * routine returns, so it is safe to read the status outside of
315 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
316 idx = device_links_read_lock();
318 retval = rpm_get_suppliers(dev);
322 device_links_read_unlock(idx);
328 if (dev->power.irq_safe) {
329 spin_lock(&dev->power.lock);
332 * If the device is suspending and the callback has returned
333 * success, drop the usage counters of the suppliers that have
334 * been reference counted on its resume.
336 * Do that if resume fails too.
339 && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
340 || (dev->power.runtime_status == RPM_RESUMING && retval))) {
341 idx = device_links_read_lock();
344 rpm_put_suppliers(dev);
346 device_links_read_unlock(idx);
349 spin_lock_irq(&dev->power.lock);
356 * rpm_idle - Notify device bus type if the device can be suspended.
357 * @dev: Device to notify the bus type about.
358 * @rpmflags: Flag bits.
360 * Check if the device's runtime PM status allows it to be suspended. If
361 * another idle notification has been started earlier, return immediately. If
362 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
363 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
364 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
366 * This function must be called under dev->power.lock with interrupts disabled.
368 static int rpm_idle(struct device *dev, int rpmflags)
370 int (*callback)(struct device *);
373 trace_rpm_idle_rcuidle(dev, rpmflags);
374 retval = rpm_check_suspend_allowed(dev);
376 ; /* Conditions are wrong. */
378 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
379 else if (dev->power.runtime_status != RPM_ACTIVE)
383 * Any pending request other than an idle notification takes
384 * precedence over us, except that the timer may be running.
386 else if (dev->power.request_pending &&
387 dev->power.request > RPM_REQ_IDLE)
390 /* Act as though RPM_NOWAIT is always set. */
391 else if (dev->power.idle_notification)
392 retval = -EINPROGRESS;
396 /* Pending requests need to be canceled. */
397 dev->power.request = RPM_REQ_NONE;
399 if (dev->power.no_callbacks)
402 /* Carry out an asynchronous or a synchronous idle notification. */
403 if (rpmflags & RPM_ASYNC) {
404 dev->power.request = RPM_REQ_IDLE;
405 if (!dev->power.request_pending) {
406 dev->power.request_pending = true;
407 queue_work(pm_wq, &dev->power.work);
409 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
413 dev->power.idle_notification = true;
415 callback = RPM_GET_CALLBACK(dev, runtime_idle);
418 retval = __rpm_callback(callback, dev);
420 dev->power.idle_notification = false;
421 wake_up_all(&dev->power.wait_queue);
424 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
425 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
429 * rpm_callback - Run a given runtime PM callback for a given device.
430 * @cb: Runtime PM callback to run.
431 * @dev: Device to run the callback for.
433 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
440 if (dev->power.memalloc_noio) {
441 unsigned int noio_flag;
444 * Deadlock might be caused if memory allocation with
445 * GFP_KERNEL happens inside runtime_suspend and
446 * runtime_resume callbacks of one block device's
447 * ancestor or the block device itself. Network
448 * device might be thought as part of iSCSI block
449 * device, so network device and its ancestor should
450 * be marked as memalloc_noio too.
452 noio_flag = memalloc_noio_save();
453 retval = __rpm_callback(cb, dev);
454 memalloc_noio_restore(noio_flag);
456 retval = __rpm_callback(cb, dev);
459 dev->power.runtime_error = retval;
460 return retval != -EACCES ? retval : -EIO;
464 * rpm_suspend - Carry out runtime suspend of given device.
465 * @dev: Device to suspend.
466 * @rpmflags: Flag bits.
468 * Check if the device's runtime PM status allows it to be suspended.
469 * Cancel a pending idle notification, autosuspend or suspend. If
470 * another suspend has been started earlier, either return immediately
471 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
472 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
473 * otherwise run the ->runtime_suspend() callback directly. When
474 * ->runtime_suspend succeeded, if a deferred resume was requested while
475 * the callback was running then carry it out, otherwise send an idle
476 * notification for its parent (if the suspend succeeded and both
477 * ignore_children of parent->power and irq_safe of dev->power are not set).
478 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
479 * flag is set and the next autosuspend-delay expiration time is in the
480 * future, schedule another autosuspend attempt.
482 * This function must be called under dev->power.lock with interrupts disabled.
484 static int rpm_suspend(struct device *dev, int rpmflags)
485 __releases(&dev->power.lock) __acquires(&dev->power.lock)
487 int (*callback)(struct device *);
488 struct device *parent = NULL;
491 trace_rpm_suspend_rcuidle(dev, rpmflags);
494 retval = rpm_check_suspend_allowed(dev);
497 ; /* Conditions are wrong. */
499 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
500 else if (dev->power.runtime_status == RPM_RESUMING &&
501 !(rpmflags & RPM_ASYNC))
506 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
507 if ((rpmflags & RPM_AUTO)
508 && dev->power.runtime_status != RPM_SUSPENDING) {
509 u64 expires = pm_runtime_autosuspend_expiration(dev);
512 /* Pending requests need to be canceled. */
513 dev->power.request = RPM_REQ_NONE;
516 * Optimization: If the timer is already running and is
517 * set to expire at or before the autosuspend delay,
518 * avoid the overhead of resetting it. Just let it
519 * expire; pm_suspend_timer_fn() will take care of the
522 if (!(dev->power.timer_expires &&
523 dev->power.timer_expires <= expires)) {
525 * We add a slack of 25% to gather wakeups
526 * without sacrificing the granularity.
528 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
529 (NSEC_PER_MSEC >> 2);
531 dev->power.timer_expires = expires;
532 hrtimer_start_range_ns(&dev->power.suspend_timer,
533 ns_to_ktime(expires),
537 dev->power.timer_autosuspends = 1;
542 /* Other scheduled or pending requests need to be canceled. */
543 pm_runtime_cancel_pending(dev);
545 if (dev->power.runtime_status == RPM_SUSPENDING) {
548 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
549 retval = -EINPROGRESS;
553 if (dev->power.irq_safe) {
554 spin_unlock(&dev->power.lock);
558 spin_lock(&dev->power.lock);
562 /* Wait for the other suspend running in parallel with us. */
564 prepare_to_wait(&dev->power.wait_queue, &wait,
565 TASK_UNINTERRUPTIBLE);
566 if (dev->power.runtime_status != RPM_SUSPENDING)
569 spin_unlock_irq(&dev->power.lock);
573 spin_lock_irq(&dev->power.lock);
575 finish_wait(&dev->power.wait_queue, &wait);
579 if (dev->power.no_callbacks)
580 goto no_callback; /* Assume success. */
582 /* Carry out an asynchronous or a synchronous suspend. */
583 if (rpmflags & RPM_ASYNC) {
584 dev->power.request = (rpmflags & RPM_AUTO) ?
585 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
586 if (!dev->power.request_pending) {
587 dev->power.request_pending = true;
588 queue_work(pm_wq, &dev->power.work);
593 __update_runtime_status(dev, RPM_SUSPENDING);
595 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
597 dev_pm_enable_wake_irq_check(dev, true);
598 retval = rpm_callback(callback, dev);
603 __update_runtime_status(dev, RPM_SUSPENDED);
604 pm_runtime_deactivate_timer(dev);
607 parent = dev->parent;
608 atomic_add_unless(&parent->power.child_count, -1, 0);
610 wake_up_all(&dev->power.wait_queue);
612 if (dev->power.deferred_resume) {
613 dev->power.deferred_resume = false;
619 /* Maybe the parent is now able to suspend. */
620 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
621 spin_unlock(&dev->power.lock);
623 spin_lock(&parent->power.lock);
624 rpm_idle(parent, RPM_ASYNC);
625 spin_unlock(&parent->power.lock);
627 spin_lock(&dev->power.lock);
631 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
636 dev_pm_disable_wake_irq_check(dev);
637 __update_runtime_status(dev, RPM_ACTIVE);
638 dev->power.deferred_resume = false;
639 wake_up_all(&dev->power.wait_queue);
641 if (retval == -EAGAIN || retval == -EBUSY) {
642 dev->power.runtime_error = 0;
645 * If the callback routine failed an autosuspend, and
646 * if the last_busy time has been updated so that there
647 * is a new autosuspend expiration time, automatically
648 * reschedule another autosuspend.
650 if ((rpmflags & RPM_AUTO) &&
651 pm_runtime_autosuspend_expiration(dev) != 0)
654 pm_runtime_cancel_pending(dev);
660 * rpm_resume - Carry out runtime resume of given device.
661 * @dev: Device to resume.
662 * @rpmflags: Flag bits.
664 * Check if the device's runtime PM status allows it to be resumed. Cancel
665 * any scheduled or pending requests. If another resume has been started
666 * earlier, either return immediately or wait for it to finish, depending on the
667 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
668 * parallel with this function, either tell the other process to resume after
669 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
670 * flag is set then queue a resume request; otherwise run the
671 * ->runtime_resume() callback directly. Queue an idle notification for the
672 * device if the resume succeeded.
674 * This function must be called under dev->power.lock with interrupts disabled.
676 static int rpm_resume(struct device *dev, int rpmflags)
677 __releases(&dev->power.lock) __acquires(&dev->power.lock)
679 int (*callback)(struct device *);
680 struct device *parent = NULL;
683 trace_rpm_resume_rcuidle(dev, rpmflags);
686 if (dev->power.runtime_error)
688 else if (dev->power.disable_depth == 1 && dev->power.is_suspended
689 && dev->power.runtime_status == RPM_ACTIVE)
691 else if (dev->power.disable_depth > 0)
697 * Other scheduled or pending requests need to be canceled. Small
698 * optimization: If an autosuspend timer is running, leave it running
699 * rather than cancelling it now only to restart it again in the near
702 dev->power.request = RPM_REQ_NONE;
703 if (!dev->power.timer_autosuspends)
704 pm_runtime_deactivate_timer(dev);
706 if (dev->power.runtime_status == RPM_ACTIVE) {
711 if (dev->power.runtime_status == RPM_RESUMING
712 || dev->power.runtime_status == RPM_SUSPENDING) {
715 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
716 if (dev->power.runtime_status == RPM_SUSPENDING)
717 dev->power.deferred_resume = true;
719 retval = -EINPROGRESS;
723 if (dev->power.irq_safe) {
724 spin_unlock(&dev->power.lock);
728 spin_lock(&dev->power.lock);
732 /* Wait for the operation carried out in parallel with us. */
734 prepare_to_wait(&dev->power.wait_queue, &wait,
735 TASK_UNINTERRUPTIBLE);
736 if (dev->power.runtime_status != RPM_RESUMING
737 && dev->power.runtime_status != RPM_SUSPENDING)
740 spin_unlock_irq(&dev->power.lock);
744 spin_lock_irq(&dev->power.lock);
746 finish_wait(&dev->power.wait_queue, &wait);
751 * See if we can skip waking up the parent. This is safe only if
752 * power.no_callbacks is set, because otherwise we don't know whether
753 * the resume will actually succeed.
755 if (dev->power.no_callbacks && !parent && dev->parent) {
756 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
757 if (dev->parent->power.disable_depth > 0
758 || dev->parent->power.ignore_children
759 || dev->parent->power.runtime_status == RPM_ACTIVE) {
760 atomic_inc(&dev->parent->power.child_count);
761 spin_unlock(&dev->parent->power.lock);
763 goto no_callback; /* Assume success. */
765 spin_unlock(&dev->parent->power.lock);
768 /* Carry out an asynchronous or a synchronous resume. */
769 if (rpmflags & RPM_ASYNC) {
770 dev->power.request = RPM_REQ_RESUME;
771 if (!dev->power.request_pending) {
772 dev->power.request_pending = true;
773 queue_work(pm_wq, &dev->power.work);
779 if (!parent && dev->parent) {
781 * Increment the parent's usage counter and resume it if
782 * necessary. Not needed if dev is irq-safe; then the
783 * parent is permanently resumed.
785 parent = dev->parent;
786 if (dev->power.irq_safe)
788 spin_unlock(&dev->power.lock);
790 pm_runtime_get_noresume(parent);
792 spin_lock(&parent->power.lock);
794 * Resume the parent if it has runtime PM enabled and not been
795 * set to ignore its children.
797 if (!parent->power.disable_depth
798 && !parent->power.ignore_children) {
799 rpm_resume(parent, 0);
800 if (parent->power.runtime_status != RPM_ACTIVE)
803 spin_unlock(&parent->power.lock);
805 spin_lock(&dev->power.lock);
812 if (dev->power.no_callbacks)
813 goto no_callback; /* Assume success. */
815 __update_runtime_status(dev, RPM_RESUMING);
817 callback = RPM_GET_CALLBACK(dev, runtime_resume);
819 dev_pm_disable_wake_irq_check(dev);
820 retval = rpm_callback(callback, dev);
822 __update_runtime_status(dev, RPM_SUSPENDED);
823 pm_runtime_cancel_pending(dev);
824 dev_pm_enable_wake_irq_check(dev, false);
827 __update_runtime_status(dev, RPM_ACTIVE);
828 pm_runtime_mark_last_busy(dev);
830 atomic_inc(&parent->power.child_count);
832 wake_up_all(&dev->power.wait_queue);
835 rpm_idle(dev, RPM_ASYNC);
838 if (parent && !dev->power.irq_safe) {
839 spin_unlock_irq(&dev->power.lock);
841 pm_runtime_put(parent);
843 spin_lock_irq(&dev->power.lock);
846 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
852 * pm_runtime_work - Universal runtime PM work function.
853 * @work: Work structure used for scheduling the execution of this function.
855 * Use @work to get the device object the work is to be done for, determine what
856 * is to be done and execute the appropriate runtime PM function.
858 static void pm_runtime_work(struct work_struct *work)
860 struct device *dev = container_of(work, struct device, power.work);
861 enum rpm_request req;
863 spin_lock_irq(&dev->power.lock);
865 if (!dev->power.request_pending)
868 req = dev->power.request;
869 dev->power.request = RPM_REQ_NONE;
870 dev->power.request_pending = false;
876 rpm_idle(dev, RPM_NOWAIT);
878 case RPM_REQ_SUSPEND:
879 rpm_suspend(dev, RPM_NOWAIT);
881 case RPM_REQ_AUTOSUSPEND:
882 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
885 rpm_resume(dev, RPM_NOWAIT);
890 spin_unlock_irq(&dev->power.lock);
894 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
895 * @data: Device pointer passed by pm_schedule_suspend().
897 * Check if the time is right and queue a suspend request.
899 static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer)
901 struct device *dev = container_of(timer, struct device, power.suspend_timer);
905 spin_lock_irqsave(&dev->power.lock, flags);
907 expires = dev->power.timer_expires;
909 * If 'expires' is after the current time, we've been called
912 if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
913 dev->power.timer_expires = 0;
914 rpm_suspend(dev, dev->power.timer_autosuspends ?
915 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
918 spin_unlock_irqrestore(&dev->power.lock, flags);
920 return HRTIMER_NORESTART;
924 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
925 * @dev: Device to suspend.
926 * @delay: Time to wait before submitting a suspend request, in milliseconds.
928 int pm_schedule_suspend(struct device *dev, unsigned int delay)
934 spin_lock_irqsave(&dev->power.lock, flags);
937 retval = rpm_suspend(dev, RPM_ASYNC);
941 retval = rpm_check_suspend_allowed(dev);
945 /* Other scheduled or pending requests need to be canceled. */
946 pm_runtime_cancel_pending(dev);
948 expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
949 dev->power.timer_expires = expires;
950 dev->power.timer_autosuspends = 0;
951 hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
954 spin_unlock_irqrestore(&dev->power.lock, flags);
958 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
961 * __pm_runtime_idle - Entry point for runtime idle operations.
962 * @dev: Device to send idle notification for.
963 * @rpmflags: Flag bits.
965 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
966 * return immediately if it is larger than zero. Then carry out an idle
967 * notification, either synchronous or asynchronous.
969 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
970 * or if pm_runtime_irq_safe() has been called.
972 int __pm_runtime_idle(struct device *dev, int rpmflags)
977 if (rpmflags & RPM_GET_PUT) {
978 if (!atomic_dec_and_test(&dev->power.usage_count))
982 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
984 spin_lock_irqsave(&dev->power.lock, flags);
985 retval = rpm_idle(dev, rpmflags);
986 spin_unlock_irqrestore(&dev->power.lock, flags);
990 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
993 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
994 * @dev: Device to suspend.
995 * @rpmflags: Flag bits.
997 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
998 * return immediately if it is larger than zero. Then carry out a suspend,
999 * either synchronous or asynchronous.
1001 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1002 * or if pm_runtime_irq_safe() has been called.
1004 int __pm_runtime_suspend(struct device *dev, int rpmflags)
1006 unsigned long flags;
1009 if (rpmflags & RPM_GET_PUT) {
1010 if (!atomic_dec_and_test(&dev->power.usage_count))
1014 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1016 spin_lock_irqsave(&dev->power.lock, flags);
1017 retval = rpm_suspend(dev, rpmflags);
1018 spin_unlock_irqrestore(&dev->power.lock, flags);
1022 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1025 * __pm_runtime_resume - Entry point for runtime resume operations.
1026 * @dev: Device to resume.
1027 * @rpmflags: Flag bits.
1029 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
1030 * carry out a resume, either synchronous or asynchronous.
1032 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1033 * or if pm_runtime_irq_safe() has been called.
1035 int __pm_runtime_resume(struct device *dev, int rpmflags)
1037 unsigned long flags;
1040 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1041 dev->power.runtime_status != RPM_ACTIVE);
1043 if (rpmflags & RPM_GET_PUT)
1044 atomic_inc(&dev->power.usage_count);
1046 spin_lock_irqsave(&dev->power.lock, flags);
1047 retval = rpm_resume(dev, rpmflags);
1048 spin_unlock_irqrestore(&dev->power.lock, flags);
1052 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1055 * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
1056 * @dev: Device to handle.
1058 * Return -EINVAL if runtime PM is disabled for the device.
1060 * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
1061 * and the runtime PM usage counter is nonzero, increment the counter and
1062 * return 1. Otherwise return 0 without changing the counter.
1064 int pm_runtime_get_if_in_use(struct device *dev)
1066 unsigned long flags;
1069 spin_lock_irqsave(&dev->power.lock, flags);
1070 retval = dev->power.disable_depth > 0 ? -EINVAL :
1071 dev->power.runtime_status == RPM_ACTIVE
1072 && atomic_inc_not_zero(&dev->power.usage_count);
1073 spin_unlock_irqrestore(&dev->power.lock, flags);
1076 EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
1079 * __pm_runtime_set_status - Set runtime PM status of a device.
1080 * @dev: Device to handle.
1081 * @status: New runtime PM status of the device.
1083 * If runtime PM of the device is disabled or its power.runtime_error field is
1084 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1085 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1086 * However, if the device has a parent and the parent is not active, and the
1087 * parent's power.ignore_children flag is unset, the device's status cannot be
1088 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1090 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1091 * and the device parent's counter of unsuspended children is modified to
1092 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
1093 * notification request for the parent is submitted.
1095 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1097 struct device *parent = dev->parent;
1098 unsigned long flags;
1099 bool notify_parent = false;
1102 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1105 spin_lock_irqsave(&dev->power.lock, flags);
1107 if (!dev->power.runtime_error && !dev->power.disable_depth) {
1112 if (dev->power.runtime_status == status || !parent)
1115 if (status == RPM_SUSPENDED) {
1116 atomic_add_unless(&parent->power.child_count, -1, 0);
1117 notify_parent = !parent->power.ignore_children;
1119 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1122 * It is invalid to put an active child under a parent that is
1123 * not active, has runtime PM enabled and the
1124 * 'power.ignore_children' flag unset.
1126 if (!parent->power.disable_depth
1127 && !parent->power.ignore_children
1128 && parent->power.runtime_status != RPM_ACTIVE) {
1129 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1133 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1134 atomic_inc(&parent->power.child_count);
1137 spin_unlock(&parent->power.lock);
1144 __update_runtime_status(dev, status);
1145 dev->power.runtime_error = 0;
1147 spin_unlock_irqrestore(&dev->power.lock, flags);
1150 pm_request_idle(parent);
1154 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1157 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1158 * @dev: Device to handle.
1160 * Flush all pending requests for the device from pm_wq and wait for all
1161 * runtime PM operations involving the device in progress to complete.
1163 * Should be called under dev->power.lock with interrupts disabled.
1165 static void __pm_runtime_barrier(struct device *dev)
1167 pm_runtime_deactivate_timer(dev);
1169 if (dev->power.request_pending) {
1170 dev->power.request = RPM_REQ_NONE;
1171 spin_unlock_irq(&dev->power.lock);
1173 cancel_work_sync(&dev->power.work);
1175 spin_lock_irq(&dev->power.lock);
1176 dev->power.request_pending = false;
1179 if (dev->power.runtime_status == RPM_SUSPENDING
1180 || dev->power.runtime_status == RPM_RESUMING
1181 || dev->power.idle_notification) {
1184 /* Suspend, wake-up or idle notification in progress. */
1186 prepare_to_wait(&dev->power.wait_queue, &wait,
1187 TASK_UNINTERRUPTIBLE);
1188 if (dev->power.runtime_status != RPM_SUSPENDING
1189 && dev->power.runtime_status != RPM_RESUMING
1190 && !dev->power.idle_notification)
1192 spin_unlock_irq(&dev->power.lock);
1196 spin_lock_irq(&dev->power.lock);
1198 finish_wait(&dev->power.wait_queue, &wait);
1203 * pm_runtime_barrier - Flush pending requests and wait for completions.
1204 * @dev: Device to handle.
1206 * Prevent the device from being suspended by incrementing its usage counter and
1207 * if there's a pending resume request for the device, wake the device up.
1208 * Next, make sure that all pending requests for the device have been flushed
1209 * from pm_wq and wait for all runtime PM operations involving the device in
1210 * progress to complete.
1213 * 1, if there was a resume request pending and the device had to be woken up,
1216 int pm_runtime_barrier(struct device *dev)
1220 pm_runtime_get_noresume(dev);
1221 spin_lock_irq(&dev->power.lock);
1223 if (dev->power.request_pending
1224 && dev->power.request == RPM_REQ_RESUME) {
1229 __pm_runtime_barrier(dev);
1231 spin_unlock_irq(&dev->power.lock);
1232 pm_runtime_put_noidle(dev);
1236 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1239 * __pm_runtime_disable - Disable runtime PM of a device.
1240 * @dev: Device to handle.
1241 * @check_resume: If set, check if there's a resume request for the device.
1243 * Increment power.disable_depth for the device and if it was zero previously,
1244 * cancel all pending runtime PM requests for the device and wait for all
1245 * operations in progress to complete. The device can be either active or
1246 * suspended after its runtime PM has been disabled.
1248 * If @check_resume is set and there's a resume request pending when
1249 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1250 * function will wake up the device before disabling its runtime PM.
1252 void __pm_runtime_disable(struct device *dev, bool check_resume)
1254 spin_lock_irq(&dev->power.lock);
1256 if (dev->power.disable_depth > 0) {
1257 dev->power.disable_depth++;
1262 * Wake up the device if there's a resume request pending, because that
1263 * means there probably is some I/O to process and disabling runtime PM
1264 * shouldn't prevent the device from processing the I/O.
1266 if (check_resume && dev->power.request_pending
1267 && dev->power.request == RPM_REQ_RESUME) {
1269 * Prevent suspends and idle notifications from being carried
1270 * out after we have woken up the device.
1272 pm_runtime_get_noresume(dev);
1276 pm_runtime_put_noidle(dev);
1279 if (!dev->power.disable_depth++)
1280 __pm_runtime_barrier(dev);
1283 spin_unlock_irq(&dev->power.lock);
1285 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1288 * pm_runtime_enable - Enable runtime PM of a device.
1289 * @dev: Device to handle.
1291 void pm_runtime_enable(struct device *dev)
1293 unsigned long flags;
1295 spin_lock_irqsave(&dev->power.lock, flags);
1297 if (dev->power.disable_depth > 0)
1298 dev->power.disable_depth--;
1300 dev_warn(dev, "Unbalanced %s!\n", __func__);
1302 WARN(!dev->power.disable_depth &&
1303 dev->power.runtime_status == RPM_SUSPENDED &&
1304 !dev->power.ignore_children &&
1305 atomic_read(&dev->power.child_count) > 0,
1306 "Enabling runtime PM for inactive device (%s) with active children\n",
1309 spin_unlock_irqrestore(&dev->power.lock, flags);
1311 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1314 * pm_runtime_forbid - Block runtime PM of a device.
1315 * @dev: Device to handle.
1317 * Increase the device's usage count and clear its power.runtime_auto flag,
1318 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1321 void pm_runtime_forbid(struct device *dev)
1323 spin_lock_irq(&dev->power.lock);
1324 if (!dev->power.runtime_auto)
1327 dev->power.runtime_auto = false;
1328 atomic_inc(&dev->power.usage_count);
1332 spin_unlock_irq(&dev->power.lock);
1334 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1337 * pm_runtime_allow - Unblock runtime PM of a device.
1338 * @dev: Device to handle.
1340 * Decrease the device's usage count and set its power.runtime_auto flag.
1342 void pm_runtime_allow(struct device *dev)
1344 spin_lock_irq(&dev->power.lock);
1345 if (dev->power.runtime_auto)
1348 dev->power.runtime_auto = true;
1349 if (atomic_dec_and_test(&dev->power.usage_count))
1350 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1353 spin_unlock_irq(&dev->power.lock);
1355 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1358 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1359 * @dev: Device to handle.
1361 * Set the power.no_callbacks flag, which tells the PM core that this
1362 * device is power-managed through its parent and has no runtime PM
1363 * callbacks of its own. The runtime sysfs attributes will be removed.
1365 void pm_runtime_no_callbacks(struct device *dev)
1367 spin_lock_irq(&dev->power.lock);
1368 dev->power.no_callbacks = 1;
1369 spin_unlock_irq(&dev->power.lock);
1370 if (device_is_registered(dev))
1371 rpm_sysfs_remove(dev);
1373 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1376 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1377 * @dev: Device to handle
1379 * Set the power.irq_safe flag, which tells the PM core that the
1380 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1381 * always be invoked with the spinlock held and interrupts disabled. It also
1382 * causes the parent's usage counter to be permanently incremented, preventing
1383 * the parent from runtime suspending -- otherwise an irq-safe child might have
1384 * to wait for a non-irq-safe parent.
1386 void pm_runtime_irq_safe(struct device *dev)
1389 pm_runtime_get_sync(dev->parent);
1390 spin_lock_irq(&dev->power.lock);
1391 dev->power.irq_safe = 1;
1392 spin_unlock_irq(&dev->power.lock);
1394 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1397 * update_autosuspend - Handle a change to a device's autosuspend settings.
1398 * @dev: Device to handle.
1399 * @old_delay: The former autosuspend_delay value.
1400 * @old_use: The former use_autosuspend value.
1402 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1403 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1405 * This function must be called under dev->power.lock with interrupts disabled.
1407 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1409 int delay = dev->power.autosuspend_delay;
1411 /* Should runtime suspend be prevented now? */
1412 if (dev->power.use_autosuspend && delay < 0) {
1414 /* If it used to be allowed then prevent it. */
1415 if (!old_use || old_delay >= 0) {
1416 atomic_inc(&dev->power.usage_count);
1421 /* Runtime suspend should be allowed now. */
1424 /* If it used to be prevented then allow it. */
1425 if (old_use && old_delay < 0)
1426 atomic_dec(&dev->power.usage_count);
1428 /* Maybe we can autosuspend now. */
1429 rpm_idle(dev, RPM_AUTO);
1434 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1435 * @dev: Device to handle.
1436 * @delay: Value of the new delay in milliseconds.
1438 * Set the device's power.autosuspend_delay value. If it changes to negative
1439 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1440 * changes the other way, allow runtime suspends.
1442 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1444 int old_delay, old_use;
1446 spin_lock_irq(&dev->power.lock);
1447 old_delay = dev->power.autosuspend_delay;
1448 old_use = dev->power.use_autosuspend;
1449 dev->power.autosuspend_delay = delay;
1450 update_autosuspend(dev, old_delay, old_use);
1451 spin_unlock_irq(&dev->power.lock);
1453 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1456 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1457 * @dev: Device to handle.
1458 * @use: New value for use_autosuspend.
1460 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1461 * suspends as needed.
1463 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1465 int old_delay, old_use;
1467 spin_lock_irq(&dev->power.lock);
1468 old_delay = dev->power.autosuspend_delay;
1469 old_use = dev->power.use_autosuspend;
1470 dev->power.use_autosuspend = use;
1471 update_autosuspend(dev, old_delay, old_use);
1472 spin_unlock_irq(&dev->power.lock);
1474 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1477 * pm_runtime_init - Initialize runtime PM fields in given device object.
1478 * @dev: Device object to initialize.
1480 void pm_runtime_init(struct device *dev)
1482 dev->power.runtime_status = RPM_SUSPENDED;
1483 dev->power.idle_notification = false;
1485 dev->power.disable_depth = 1;
1486 atomic_set(&dev->power.usage_count, 0);
1488 dev->power.runtime_error = 0;
1490 atomic_set(&dev->power.child_count, 0);
1491 pm_suspend_ignore_children(dev, false);
1492 dev->power.runtime_auto = true;
1494 dev->power.request_pending = false;
1495 dev->power.request = RPM_REQ_NONE;
1496 dev->power.deferred_resume = false;
1497 dev->power.accounting_timestamp = jiffies;
1498 INIT_WORK(&dev->power.work, pm_runtime_work);
1500 dev->power.timer_expires = 0;
1501 hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1502 dev->power.suspend_timer.function = pm_suspend_timer_fn;
1504 init_waitqueue_head(&dev->power.wait_queue);
1508 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1509 * @dev: Device object to re-initialize.
1511 void pm_runtime_reinit(struct device *dev)
1513 if (!pm_runtime_enabled(dev)) {
1514 if (dev->power.runtime_status == RPM_ACTIVE)
1515 pm_runtime_set_suspended(dev);
1516 if (dev->power.irq_safe) {
1517 spin_lock_irq(&dev->power.lock);
1518 dev->power.irq_safe = 0;
1519 spin_unlock_irq(&dev->power.lock);
1521 pm_runtime_put(dev->parent);
1527 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1528 * @dev: Device object being removed from device hierarchy.
1530 void pm_runtime_remove(struct device *dev)
1532 __pm_runtime_disable(dev, false);
1533 pm_runtime_reinit(dev);
1537 * pm_runtime_clean_up_links - Prepare links to consumers for driver removal.
1538 * @dev: Device whose driver is going to be removed.
1540 * Check links from this device to any consumers and if any of them have active
1541 * runtime PM references to the device, drop the usage counter of the device
1544 * Links with the DL_FLAG_STATELESS flag set are ignored.
1546 * Since the device is guaranteed to be runtime-active at the point this is
1547 * called, nothing else needs to be done here.
1549 * Moreover, this is called after device_links_busy() has returned 'false', so
1550 * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and
1551 * therefore rpm_active can't be manipulated concurrently.
1553 void pm_runtime_clean_up_links(struct device *dev)
1555 struct device_link *link;
1558 idx = device_links_read_lock();
1560 list_for_each_entry_rcu(link, &dev->links.consumers, s_node) {
1561 if (link->flags & DL_FLAG_STATELESS)
1564 if (link->rpm_active) {
1565 pm_runtime_put_noidle(dev);
1566 link->rpm_active = false;
1570 device_links_read_unlock(idx);
1574 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1575 * @dev: Consumer device.
1577 void pm_runtime_get_suppliers(struct device *dev)
1579 struct device_link *link;
1582 idx = device_links_read_lock();
1584 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1585 if (link->flags & DL_FLAG_PM_RUNTIME)
1586 pm_runtime_get_sync(link->supplier);
1588 device_links_read_unlock(idx);
1592 * pm_runtime_put_suppliers - Drop references to supplier devices.
1593 * @dev: Consumer device.
1595 void pm_runtime_put_suppliers(struct device *dev)
1597 struct device_link *link;
1600 idx = device_links_read_lock();
1602 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1603 if (link->flags & DL_FLAG_PM_RUNTIME)
1604 pm_runtime_put(link->supplier);
1606 device_links_read_unlock(idx);
1609 void pm_runtime_new_link(struct device *dev)
1611 spin_lock_irq(&dev->power.lock);
1612 dev->power.links_count++;
1613 spin_unlock_irq(&dev->power.lock);
1616 void pm_runtime_drop_link(struct device *dev)
1618 rpm_put_suppliers(dev);
1620 spin_lock_irq(&dev->power.lock);
1621 WARN_ON(dev->power.links_count == 0);
1622 dev->power.links_count--;
1623 spin_unlock_irq(&dev->power.lock);
1626 static bool pm_runtime_need_not_resume(struct device *dev)
1628 return atomic_read(&dev->power.usage_count) <= 1 &&
1629 (atomic_read(&dev->power.child_count) == 0 ||
1630 dev->power.ignore_children);
1634 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1635 * @dev: Device to suspend.
1637 * Disable runtime PM so we safely can check the device's runtime PM status and
1638 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1639 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
1640 * usage and children counters don't indicate that the device was in use before
1641 * the system-wide transition under way, decrement its parent's children counter
1642 * (if there is a parent). Keep runtime PM disabled to preserve the state
1643 * unless we encounter errors.
1645 * Typically this function may be invoked from a system suspend callback to make
1646 * sure the device is put into low power state and it should only be used during
1647 * system-wide PM transitions to sleep states. It assumes that the analogous
1648 * pm_runtime_force_resume() will be used to resume the device.
1650 int pm_runtime_force_suspend(struct device *dev)
1652 int (*callback)(struct device *);
1655 pm_runtime_disable(dev);
1656 if (pm_runtime_status_suspended(dev))
1659 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1661 ret = callback ? callback(dev) : 0;
1666 * If the device can stay in suspend after the system-wide transition
1667 * to the working state that will follow, drop the children counter of
1668 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1669 * function will be called again for it in the meantime.
1671 if (pm_runtime_need_not_resume(dev))
1672 pm_runtime_set_suspended(dev);
1674 __update_runtime_status(dev, RPM_SUSPENDED);
1679 pm_runtime_enable(dev);
1682 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1685 * pm_runtime_force_resume - Force a device into resume state if needed.
1686 * @dev: Device to resume.
1688 * Prior invoking this function we expect the user to have brought the device
1689 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1690 * those actions and bring the device into full power, if it is expected to be
1691 * used on system resume. In the other case, we defer the resume to be managed
1694 * Typically this function may be invoked from a system resume callback.
1696 int pm_runtime_force_resume(struct device *dev)
1698 int (*callback)(struct device *);
1701 if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev))
1705 * The value of the parent's children counter is correct already, so
1706 * just update the status of the device.
1708 __update_runtime_status(dev, RPM_ACTIVE);
1710 callback = RPM_GET_CALLBACK(dev, runtime_resume);
1712 ret = callback ? callback(dev) : 0;
1714 pm_runtime_set_suspended(dev);
1718 pm_runtime_mark_last_busy(dev);
1720 pm_runtime_enable(dev);
1723 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);