Lines Matching +full:run +full:- +full:time
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
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
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
135 fatal error and will refuse to run the helper functions described in Section
140 The idle callback (a subsystem-level one, if present, or the driver one) is
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
216 timer is running and will expire at that time, otherwise the timer is not
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 - the last runtime PM status of the device captured before disabling runtime
273 - if set, indicates that the user space has allowed the device driver to
274 power manage the device at run time via the /sys/devices/.../power/control
279 - indicates that the device does not use the runtime PM callbacks (see
284 - indicates that the ->runtime_suspend() and ->runtime_resume() callbacks
288 - indicates that the device's driver supports delayed autosuspend (see
293 - indicates that the PM core should attempt to carry out an autosuspend
297 - the delay time (in milliseconds) to be used for autosuspend
300 - the time (in jiffies) when the pm_runtime_mark_last_busy() helper
313 - initialize the device runtime PM fields in 'struct dev_pm_info'
316 - make sure that the runtime PM of the device will be disabled after
320 - execute the subsystem-level idle callback for the device; returns an
321 error code on failure, where -EINPROGRESS means that ->runtime_idle() is
323 then run pm_runtime_autosuspend(dev) and return its result
326 - execute the subsystem-level suspend callback for the device; returns 0 on
328 error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt
329 to suspend the device again in future and -EACCES means that
333 - same as pm_runtime_suspend() except that the autosuspend delay is taken
335 not yet expired then an autosuspend is scheduled for the appropriate time
339 - execute the subsystem-level resume callback for the device; returns 0 on
342 changing from 0 to 1) or error code on failure, where -EAGAIN means it may
344 'power.runtime_error' should be checked additionally, and -EACCES means
345 that the callback could not be run, because 'power.disable_depth' was
349 - run pm_runtime_resume(dev) and if successful, increment the device's
353 - submit a request to execute the subsystem-level idle callback for the
358 - schedule the execution of the subsystem-level suspend callback for the
363 - schedule the execution of the subsystem-level suspend callback for the
364 device in future, where 'delay' is the time to wait before queuing up a
369 ->runtime_suspend() is already scheduled and not yet expired, the new
370 value of 'delay' will be used as the time to wait
373 - submit a request to execute the subsystem-level resume callback for the
379 - increment the device's usage counter
382 - increment the device's usage counter, run pm_request_resume(dev) and
386 - increment the device's usage counter, run pm_runtime_resume(dev) and
394 - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
400 - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
405 - decrement the device's usage counter
408 - decrement the device's usage counter; if the result is 0 then run
412 - does the same as __pm_runtime_put_autosuspend() for now, but in the
416 - decrement the device's usage counter; if the result is 0 then run
420 - decrement the device's usage counter; if the result is 0 then run
424 - decrement the device's usage counter; if the result is 0 then run
428 - decrement the device's usage counter; if the result is 0 then run
432 - decrement the device's 'power.disable_depth' field; if that field is equal
433 to zero, the runtime PM helper functions can execute subsystem-level
437 - increment the device's 'power.disable_depth' field (if the value of that
438 field was previously zero, this prevents subsystem-level runtime PM
439 callbacks from being run for the device), make sure that all of the
442 necessary to execute the subsystem-level resume callback for the device
446 - check if there's a resume request pending for the device and resume it
450 necessary to execute the subsystem-level resume callback for the device to
454 - set/unset the power.ignore_children flag of the device
457 - clear the device's 'power.runtime_error' flag, set the device's runtime
465 - clear the device's 'power.runtime_error' flag, set the device's runtime
472 - return true if the device's runtime PM status is 'active' or its
476 - return true if the device's runtime PM status is 'suspended' and its
480 - return true if the device's runtime PM status is 'suspended'
483 - set the power.runtime_auto flag for the device and decrease its usage
485 effectively allow the device to be power managed at run time)
488 - unset the power.runtime_auto flag for the device and increase its usage
490 effectively prevent the device from being power managed at run time)
493 - set the power.no_callbacks flag for the device and remove the runtime
498 - set the power.irq_safe flag for the device, causing the runtime-PM
502 - return true if power.irq_safe flag was set for the device, causing
503 the runtime-PM callbacks to be invoked with interrupts off
506 - set the power.last_busy field to the current time
509 - set the power.use_autosuspend flag, enabling autosuspend delays; call
514 - clear the power.use_autosuspend flag, disabling autosuspend delays;
519 - set the power.autosuspend_delay value to 'delay' (expressed in
528 - calculate the time when the current autosuspend delay period will expire,
529 based on power.last_busy and power.autosuspend_delay; if the delay time
530 is 1000 ms or larger then the expiration time is rounded up to the
532 power.use_autosuspend isn't set, otherwise returns the expiration time
537 - pm_request_idle()
538 - pm_request_autosuspend()
539 - pm_schedule_suspend()
540 - pm_request_resume()
541 - pm_runtime_get_noresume()
542 - pm_runtime_get()
543 - pm_runtime_put_noidle()
544 - pm_runtime_put()
545 - pm_runtime_put_autosuspend()
546 - __pm_runtime_put_autosuspend()
547 - pm_runtime_enable()
548 - pm_suspend_ignore_children()
549 - pm_runtime_set_active()
550 - pm_runtime_set_suspended()
551 - pm_runtime_suspended()
552 - pm_runtime_mark_last_busy()
553 - pm_runtime_autosuspend_expiration()
558 - pm_runtime_idle()
559 - pm_runtime_suspend()
560 - pm_runtime_autosuspend()
561 - pm_runtime_resume()
562 - pm_runtime_get_sync()
563 - pm_runtime_put_sync()
564 - pm_runtime_put_sync_suspend()
565 - pm_runtime_put_sync_autosuspend()
572 -EAGAIN until pm_runtime_enable() is called for the device.
583 parent won't be able to suspend at run time, using the PM core's helper
594 ->probe() callback will likely need to wake it up using one of the PM core's
605 It may be desirable to suspend the device once ->probe() has finished.
607 request to execute the subsystem-level idle callback for the device at that
608 time. A driver that makes use of the runtime autosuspend feature may want to
609 update the last busy mark before returning from ->probe().
620 calling pm_runtime_suspend() from their ->remove() routines, the driver core
623 drivers to make their ->remove() callbacks avoid races with runtime PM directly,
627 Drivers in ->remove() callback should undo the runtime PM changes done
628 in ->probe(). Usually this means calling pm_runtime_disable(),
632 it at run time by changing the value of its /sys/devices/.../power/control
640 manage the device at run time, the driver may confuse it by using
647 as suspend-to-RAM and suspend-to-disk) interact with each other in a couple of
651 The device may have different wake-up settings for runtime PM and system sleep.
652 For example, remote wake-up may be enabled for runtime suspend but disallowed
654 the subsystem-level system suspend callback is responsible for changing the
655 device's wake-up setting (it may leave that to the device driver's system
664 * The device might need to switch power levels, wake-up settings, etc.
666 * Remote wake-up events might have been lost by the firmware.
681 to be updated to reflect the actual post-system sleep status. The way to do
684 - pm_runtime_disable(dev);
685 - pm_runtime_set_active(dev);
686 - pm_runtime_enable(dev);
689 ->suspend() callback and decrements it after calling the ->resume() callback.
692 following the return of the ->resume() callback, the ->runtime_idle() callback
696 or hardware operation. Instead, all hardware components are put into low-power
710 that the device appears to be runtime-suspended and its state is fine, so it
716 related to hibernation (see Documentation/driver-api/pm/devices.rst for more
724 right before executing the subsystem-level .prepare() callback for it and
726 subsystem-level .suspend() callback for it. In addition to that the PM core
728 device right before executing the subsystem-level .suspend_late() callback
732 every device right after executing the subsystem-level .resume_early()
733 callback and right after executing the subsystem-level .complete() callback
744 - invoke the ->runtime_suspend() callback provided by the driver of this
748 - invoke the ->runtime_resume() callback provided by the driver of this
752 - if the device has not been suspended at run time, invoke the ->suspend()
757 - if pm_runtime_suspended(dev) returns "false", invoke the ->suspend_noirq()
762 - invoke the ->resume() callback provided by the driver of this device and,
766 - invoke the ->resume_noirq() callback provided by the driver of this device
769 - if the device has not been suspended at run time, invoke the ->freeze()
774 - if pm_runtime_suspended(dev) returns "false", invoke the ->freeze_noirq()
779 - if the device has not been suspended at run time, invoke the ->thaw()
784 - if pm_runtime_suspended(dev) returns "false", invoke the ->thaw_noirq()
789 - if the device has not been suspended at run time, invoke the ->poweroff()
794 - if pm_runtime_suspended(dev) returns "false", run the ->poweroff_noirq()
799 - invoke the ->restore() callback provided by the driver of this device and,
803 - invoke the ->restore_noirq() callback provided by the device's driver
806 provide its own callbacks for ->runtime_idle(), ->runtime_suspend(),
807 ->runtime_resume(), ->suspend(), ->suspend_noirq(), ->resume(),
808 ->resume_noirq(), ->freeze(), ->freeze_noirq(), ->thaw(), ->thaw_noirq(),
809 ->poweroff(), ->poweroff_noirq(), ->restore(), ->restore_noirq() in the
810 subsystem-level dev_pm_ops structure.
818 8. "No-Callback" Devices
821 Some "devices" are only logical sub-devices of their parent and cannot be
822 power-managed on their own. (The prototype example is a USB interface. Entire
823 USB devices can go into low-power mode or send wake-up requests, but neither is
825 need of runtime PM callbacks; if the callbacks did exist, ->runtime_suspend()
826 and ->runtime_resume() would always return 0 without doing anything else and
827 ->runtime_idle() would always call pm_runtime_suspend().
833 prevent the non-debugging runtime PM sysfs attributes from being created.
836 ->runtime_idle(), ->runtime_suspend(), or ->runtime_resume() callbacks.
854 9. Autosuspend, or automatically-delayed suspends
857 Changing a device's power state isn't free; it requires both time and energy.
858 A device should be put in a low-power state only when there's some reason to
859 think it will remain in that state for a substantial time. A common heuristic
863 the heuristic ends up being non-optimal, it will still prevent devices from
864 "bouncing" too rapidly between low-power and full-power states.
882 instead of the non-autosuspend counterparts::
889 Drivers may also continue to use the non-autosuspend helper functions; they
895 autosuspend delay time has expired. If the ->runtime_suspend() callback
896 returns -EAGAIN or -EBUSY, and if the next autosuspend delay expiration time is
899 autosuspend. The ->runtime_suspend() callback can't do this rescheduling
905 synchronize ->runtime_suspend() callbacks with the arrival of I/O requests.
907 Here is a schematic pseudo-code example::
911 lock(&foo->private_lock);
913 if (foo->num_pending_requests++ == 0)
914 pm_runtime_get(&foo->dev);
915 if (!foo->is_suspended)
917 unlock(&foo->private_lock);
922 lock(&foo->private_lock);
923 if (--foo->num_pending_requests == 0) {
924 pm_runtime_mark_last_busy(&foo->dev);
925 __pm_runtime_put_autosuspend(&foo->dev);
929 unlock(&foo->private_lock);
938 lock(&foo->private_lock);
939 if (foo->num_pending_requests > 0) {
940 ret = -EBUSY;
943 foo->is_suspended = 1;
945 unlock(&foo->private_lock);
953 lock(&foo->private_lock);
955 foo->is_suspended = 0;
956 pm_runtime_mark_last_busy(&foo->dev);
957 if (foo->num_pending_requests > 0)
959 unlock(&foo->private_lock);
970 any time. If a driver cares about this, it can call
971 pm_runtime_autosuspend_expiration() from within the ->runtime_suspend()
974 -EAGAIN.