Lines Matching +full:field +full:- +full:even +full:- +full:active
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
103 status remains 'active', which means that the device _must_ be fully
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
109 is directly set to either 'active', or 'suspended' (the PM core provides
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
132 'active'.
136 4 for the device, until its status is directly set to either 'active', or
140 The idle callback (a subsystem-level one, if present, or the driver one) is
143 counter of 'active' children of the device.
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
177 'active').
179 (3) ->runtime_idle() and ->runtime_suspend() can only be executed for a device
181 'active' children of which is equal to zero, or the 'power.ignore_children'
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
335 - execute the subsystem-level resume callback for the device; returns 0 on
336 success, 1 if the device's runtime PM status was already 'active' or
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
353 - schedule the execution of the subsystem-level suspend callback for the
359 ->runtime_suspend() is already scheduled and not yet expired, the new
363 - submit a request to execute the subsystem-level resume callback for the
365 success, 1 if the device's runtime PM status was already 'active', or
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
441 PM status to 'active' and update its parent's counter of 'active'
445 which is not active and the 'power.ignore_children' flag of which is unset
448 - clear the device's 'power.runtime_error' flag, set the device's runtime
449 PM status to 'suspended' and update its parent's counter of 'active'
455 - return true if the device's runtime PM status is 'active' or its
456 'power.disable_depth' field is not equal to zero, or false otherwise
459 - return true if the device's runtime PM status is 'suspended' and its
460 'power.disable_depth' field is equal to zero, or false otherwise
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;
502 - set the power.autosuspend_delay value to 'delay' (expressed in
511 - calculate the time when the current autosuspend delay period will expire,
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.
558 Thus, if the device is initially active (i.e. it is able to process I/O), its
559 runtime PM status must be changed to 'active', with the help of
566 functions, as long as the child's status is 'active', even if the child's
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(),
619 status of the device is 'active' and call pm_runtime_forbid(). It should be
629 as suspend-to-RAM and suspend-to-disk) interact with each other in a couple of
630 ways. If a device is active when a system sleep starts, everything is
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
643 power, even if they had been suspended before the system suspend began. There
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.
658 * Even though the device was suspended, if its usage counter was > 0 then most
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,
744 if successful, change the device's runtime PM status to 'active'
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,
781 if successful, change the device's runtime PM status to 'active'
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
834 at runtime until they have been inactive for some minimum period. Even when
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.
843 Inactivity is determined based on the power.last_busy field. Drivers should
844 call pm_runtime_mark_last_busy() to update this field after carrying out I/O,
854 instead of the non-autosuspend counterparts::
861 Drivers may also continue to use the non-autosuspend helper functions; they
866 from autosuspending immediately, even though the usage counter is zero and the
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);
941 In addition, the power.autosuspend_delay field can be changed by user space at
943 pm_runtime_autosuspend_expiration() from within the ->runtime_suspend()
946 -EAGAIN.