Lines Matching +full:wakeup +full:- +full:delay
5 (C) 2009-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
18 put their PM-related work items. It is strongly recommended that pm_wq be
20 them to be synchronized with system-wide power transitions (suspend to RAM,
53 The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks
57 1. PM domain of the device, if the device's PM domain object, dev->pm_domain,
60 2. Device type of the device, if both dev->type and dev->type->pm are present.
62 3. Device class of the device, if both dev->class and dev->class->pm are
65 4. Bus type of the device, if both dev->bus and dev->bus->pm are present.
69 dev->driver->pm directly (if present).
73 and bus type. Moreover, the high-priority one will always take precedence over
74 a low-priority one. The PM domain, bus type, device type and class callbacks
75 are referred to as subsystem-level callbacks in what follows.
79 the PM core that it is safe to run the ->runtime_suspend(), ->runtime_resume()
80 and ->runtime_idle() callbacks for the given device in atomic context with
86 The subsystem-level suspend callback, if present, is _entirely_ _responsible_
88 include executing the device driver's own ->runtime_suspend() callback (from the
89 PM core's point of view it is not necessary to implement a ->runtime_suspend()
90 callback in a device driver as long as the subsystem-level suspend callback
93 * Once the subsystem-level suspend callback (or the driver suspend callback,
102 * If the suspend callback returns -EBUSY or -EAGAIN, the device's runtime PM
106 * If the suspend callback returns an error code different from -EBUSY and
107 -EAGAIN, the PM core regards this as a fatal error and will refuse to run
112 In particular, if the driver requires remote wakeup capability (i.e. hardware
115 device, then ->runtime_suspend() should return -EBUSY. On the other hand, if
117 low-power state during the execution of the suspend callback, it is expected
118 that remote wakeup will be enabled for the device. Generally, remote wakeup
119 should be enabled for all input devices put into low-power states at run time.
121 The subsystem-level resume callback, if present, is **entirely responsible** for
123 include executing the device driver's own ->runtime_resume() callback (from the
124 PM core's point of view it is not necessary to implement a ->runtime_resume()
125 callback in a device driver as long as the subsystem-level resume callback knows
128 * Once the subsystem-level resume callback (or the driver resume callback, if
140 The idle callback (a subsystem-level one, if present, or the driver one) is
158 device last busy mark, pm_runtime_mark_last_busy(), to control the delay under
160 started a delayed suspend), the routine must return a non-zero value. Negative
168 ->runtime_suspend() in parallel with ->runtime_resume() or with another
169 instance of ->runtime_suspend() for the same device) with the exception that
170 ->runtime_suspend() or ->runtime_resume() can be executed in parallel with
171 ->runtime_idle() (although ->runtime_idle() will not be started while any
174 (2) ->runtime_idle() and ->runtime_suspend() can only be executed for 'active'
175 devices (i.e. the PM core will only execute ->runtime_idle() or
176 ->runtime_suspend() for the devices the runtime PM status of which is
179 (3) ->runtime_idle() and ->runtime_suspend() can only be executed for a device
184 (4) ->runtime_resume() can only be executed for 'suspended' devices (i.e. the
185 PM core will only execute ->runtime_resume() for the devices the runtime
191 * If ->runtime_suspend() is about to be executed or there's a pending request
192 to execute it, ->runtime_idle() will not be executed for the same device.
194 * A request to execute or to schedule the execution of ->runtime_suspend()
195 will cancel any pending requests to execute ->runtime_idle() for the same
198 * If ->runtime_resume() is about to be executed or there's a pending request
201 * A request to execute ->runtime_resume() will cancel any pending or
212 - timer used for scheduling (delayed) suspend and autosuspend requests
215 - timer expiration time, in jiffies (if this is different from zero, the
220 - work structure used for queuing up requests (i.e. work items in pm_wq)
223 - wait queue used if any of the helper functions needs to wait for another
227 - lock used for synchronization
230 - the usage counter of the device
233 - the count of 'active' children of the device
236 - if set, the value of child_count is ignored (but still updated)
239 - used for disabling the helper functions (they work normally if this is
244 - if set, there was a fatal error (one of the callbacks returned error code
250 - if set, ->runtime_idle() is being executed
253 - if set, there's a pending request (i.e. a work item queued up into pm_wq)
256 - type of request that's pending (valid if request_pending is set)
259 - set if ->runtime_resume() is about to be run while ->runtime_suspend() is
264 - the runtime PM status of the device; this field's initial value is
269 - if set, indicates that the user space has allowed the device driver to
275 - indicates that the device does not use the runtime PM callbacks (see
280 - indicates that the ->runtime_suspend() and ->runtime_resume() callbacks
284 - indicates that the device's driver supports delayed autosuspend (see
289 - indicates that the PM core should attempt to carry out an autosuspend
293 - the delay time (in milliseconds) to be used for autosuspend
296 - the time (in jiffies) when the pm_runtime_mark_last_busy() helper
309 - initialize the device runtime PM fields in 'struct dev_pm_info'
312 - make sure that the runtime PM of the device will be disabled after
316 - execute the subsystem-level idle callback for the device; returns an
317 error code on failure, where -EINPROGRESS means that ->runtime_idle() is
322 - execute the subsystem-level suspend callback for the device; returns 0 on
324 error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt
325 to suspend the device again in future and -EACCES means that
329 - same as pm_runtime_suspend() except that the autosuspend delay is taken
330 `into account;` if pm_runtime_autosuspend_expiration() says the delay has
335 - execute the subsystem-level resume callback for the device; returns 0 on
337 error code on failure, where -EAGAIN means it may be safe to attempt to
339 checked additionally, and -EACCES means that 'power.disable_depth' is
343 - submit a request to execute the subsystem-level idle callback for the
348 - schedule the execution of the subsystem-level suspend callback for the
349 device when the autosuspend delay has expired; if the delay has already
352 `int pm_schedule_suspend(struct device *dev, unsigned int delay);`
353 - schedule the execution of the subsystem-level suspend callback for the
354 device in future, where 'delay' is the time to wait before queuing up a
355 suspend work item in pm_wq, in milliseconds (if 'delay' is zero, the work
358 hasn't been scheduled (or queued up if 'delay' is 0); if the execution of
359 ->runtime_suspend() is already scheduled and not yet expired, the new
360 value of 'delay' will be used as the time to wait
363 - submit a request to execute the subsystem-level resume callback for the
369 - increment the device's usage counter
372 - increment the device's usage counter, run pm_request_resume(dev) and
376 - increment the device's usage counter, run pm_runtime_resume(dev) and
380 - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
386 - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
388 or the device's usage_count is non-zero, increment the counter and
392 - decrement the device's usage counter
395 - decrement the device's usage counter; if the result is 0 then run
399 - decrement the device's usage counter; if the result is 0 then run
403 - decrement the device's usage counter; if the result is 0 then run
407 - decrement the device's usage counter; if the result is 0 then run
411 - decrement the device's usage counter; if the result is 0 then run
415 - decrement the device's 'power.disable_depth' field; if that field is equal
416 to zero, the runtime PM helper functions can execute subsystem-level
420 - increment the device's 'power.disable_depth' field (if the value of that
421 field was previously zero, this prevents subsystem-level runtime PM
425 necessary to execute the subsystem-level resume callback for the device
429 - check if there's a resume request pending for the device and resume it
433 necessary to execute the subsystem-level resume callback for the device to
437 - set/unset the power.ignore_children flag of the device
440 - clear the device's 'power.runtime_error' flag, set the device's runtime
448 - clear the device's 'power.runtime_error' flag, set the device's runtime
455 - return true if the device's runtime PM status is 'active' or its
459 - return true if the device's runtime PM status is 'suspended' and its
463 - return true if the device's runtime PM status is 'suspended'
466 - set the power.runtime_auto flag for the device and decrease its usage
471 - unset the power.runtime_auto flag for the device and increase its usage
476 - set the power.no_callbacks flag for the device and remove the runtime
481 - set the power.irq_safe flag for the device, causing the runtime-PM
485 - return true if power.irq_safe flag was set for the device, causing
486 the runtime-PM callbacks to be invoked with interrupts off
489 - set the power.last_busy field to the current time
492 - set the power.use_autosuspend flag, enabling autosuspend delays; call
497 - clear the power.use_autosuspend flag, disabling autosuspend delays;
501 `void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);`
502 - set the power.autosuspend_delay value to 'delay' (expressed in
503 milliseconds); if 'delay' is negative then runtime suspends are
511 - calculate the time when the current autosuspend delay period will expire,
512 based on power.last_busy and power.autosuspend_delay; if the delay time
514 nearest second; returns 0 if the delay period has already expired or
520 - pm_request_idle()
521 - pm_request_autosuspend()
522 - pm_schedule_suspend()
523 - pm_request_resume()
524 - pm_runtime_get_noresume()
525 - pm_runtime_get()
526 - pm_runtime_put_noidle()
527 - pm_runtime_put()
528 - pm_runtime_put_autosuspend()
529 - pm_runtime_enable()
530 - pm_suspend_ignore_children()
531 - pm_runtime_set_active()
532 - pm_runtime_set_suspended()
533 - pm_runtime_suspended()
534 - pm_runtime_mark_last_busy()
535 - pm_runtime_autosuspend_expiration()
540 - pm_runtime_idle()
541 - pm_runtime_suspend()
542 - pm_runtime_autosuspend()
543 - pm_runtime_resume()
544 - pm_runtime_get_sync()
545 - pm_runtime_put_sync()
546 - pm_runtime_put_sync_suspend()
547 - pm_runtime_put_sync_autosuspend()
554 -EAGAIN until pm_runtime_enable() is called for the device.
576 ->probe() callback will likely need to wake it up using one of the PM core's
587 It may be desirable to suspend the device once ->probe() has finished.
589 request to execute the subsystem-level idle callback for the device at that
591 update the last busy mark before returning from ->probe().
602 calling pm_runtime_suspend() from their ->remove() routines, the driver core
605 drivers to make their ->remove() callbacks avoid races with runtime PM directly,
609 Drivers in ->remove() callback should undo the runtime PM changes done
610 in ->probe(). Usually this means calling pm_runtime_disable(),
629 as suspend-to-RAM and suspend-to-disk) interact with each other in a couple of
633 The device may have different wake-up settings for runtime PM and system sleep.
634 For example, remote wake-up may be enabled for runtime suspend but disallowed
636 the subsystem-level system suspend callback is responsible for changing the
637 device's wake-up setting (it may leave that to the device driver's system
646 * The device might need to switch power levels, wake-up settings, etc.
648 * Remote wake-up events might have been lost by the firmware.
663 to be updated to reflect the actual post-system sleep status. The way to do
666 - pm_runtime_disable(dev);
667 - pm_runtime_set_active(dev);
668 - pm_runtime_enable(dev);
671 ->suspend() callback and decrements it after calling the ->resume() callback.
674 following the return of the ->resume() callback, the ->runtime_idle() callback
678 or hardware operation. Instead, all hardware components are put into low-power
692 that the device appears to be runtime-suspended and its state is fine, so it
698 related to hibernation (see Documentation/driver-api/pm/devices.rst for more
706 right before executing the subsystem-level .prepare() callback for it and
708 subsystem-level .suspend() callback for it. In addition to that the PM core
710 device right before executing the subsystem-level .suspend_late() callback
714 every device right after executing the subsystem-level .resume_early()
715 callback and right after executing the subsystem-level .complete() callback
725 - invoke the ->runtime_suspend() callback provided by the driver of this
729 - invoke the ->runtime_resume() callback provided by the driver of this
733 - if the device has not been suspended at run time, invoke the ->suspend()
738 - if pm_runtime_suspended(dev) returns "false", invoke the ->suspend_noirq()
743 - invoke the ->resume() callback provided by the driver of this device and,
747 - invoke the ->resume_noirq() callback provided by the driver of this device
750 - if the device has not been suspended at run time, invoke the ->freeze()
755 - if pm_runtime_suspended(dev) returns "false", invoke the ->freeze_noirq()
760 - if the device has not been suspended at run time, invoke the ->thaw()
765 - if pm_runtime_suspended(dev) returns "false", invoke the ->thaw_noirq()
770 - if the device has not been suspended at run time, invoke the ->poweroff()
775 - if pm_runtime_suspended(dev) returns "false", run the ->poweroff_noirq()
780 - invoke the ->restore() callback provided by the driver of this device and,
784 - invoke the ->restore_noirq() callback provided by the device's driver
787 provide its own callbacks for ->runtime_idle(), ->runtime_suspend(),
788 ->runtime_resume(), ->suspend(), ->suspend_noirq(), ->resume(),
789 ->resume_noirq(), ->freeze(), ->freeze_noirq(), ->thaw(), ->thaw_noirq(),
790 ->poweroff(), ->poweroff_noirq(), ->restore(), ->restore_noirq() in the
791 subsystem-level dev_pm_ops structure.
799 8. "No-Callback" Devices
802 Some "devices" are only logical sub-devices of their parent and cannot be
803 power-managed on their own. (The prototype example is a USB interface. Entire
804 USB devices can go into low-power mode or send wake-up requests, but neither is
806 need of runtime PM callbacks; if the callbacks did exist, ->runtime_suspend()
807 and ->runtime_resume() would always return 0 without doing anything else and
808 ->runtime_idle() would always call pm_runtime_suspend().
814 prevent the non-debugging runtime PM sysfs attributes from being created.
817 ->runtime_idle(), ->runtime_suspend(), or ->runtime_resume() callbacks.
826 9. Autosuspend, or automatically-delayed suspends
830 A device should be put in a low-power state only when there's some reason to
835 the heuristic ends up being non-optimal, it will still prevent devices from
836 "bouncing" too rapidly between low-power and full-power states.
854 instead of the non-autosuspend counterparts::
861 Drivers may also continue to use the non-autosuspend helper functions; they
862 will behave normally, which means sometimes taking the autosuspend delay into
867 autosuspend delay time has expired. If the ->runtime_suspend() callback
868 returns -EAGAIN or -EBUSY, and if the next autosuspend delay expiration time is
871 autosuspend. The ->runtime_suspend() callback can't do this rescheduling
877 synchronize ->runtime_suspend() callbacks with the arrival of I/O requests.
879 Here is a schematic pseudo-code example::
883 lock(&foo->private_lock);
885 if (foo->num_pending_requests++ == 0)
886 pm_runtime_get(&foo->dev);
887 if (!foo->is_suspended)
889 unlock(&foo->private_lock);
894 lock(&foo->private_lock);
895 if (--foo->num_pending_requests == 0) {
896 pm_runtime_mark_last_busy(&foo->dev);
897 pm_runtime_put_autosuspend(&foo->dev);
901 unlock(&foo->private_lock);
910 lock(&foo->private_lock);
911 if (foo->num_pending_requests > 0) {
912 ret = -EBUSY;
915 foo->is_suspended = 1;
917 unlock(&foo->private_lock);
925 lock(&foo->private_lock);
927 foo->is_suspended = 0;
928 pm_runtime_mark_last_busy(&foo->dev);
929 if (foo->num_pending_requests > 0)
931 unlock(&foo->private_lock);
943 pm_runtime_autosuspend_expiration() from within the ->runtime_suspend()
945 value then the delay has not yet expired and the callback should return
946 -EAGAIN.