Lines Matching +full:autosuspend +full:- +full:delay +full:- +full:ms
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
140 The idle callback (a subsystem-level one, if present, or the driver one) is
156 also respecting devices configured for autosuspend. In essence this means a
158 routine has started a delayed suspend), the routine must return a non-zero
166 ->runtime_suspend() in parallel with ->runtime_resume() or with another
167 instance of ->runtime_suspend() for the same device) with the exception that
168 ->runtime_suspend() or ->runtime_resume() can be executed in parallel with
169 ->runtime_idle() (although ->runtime_idle() will not be started while any
172 (2) ->runtime_idle() and ->runtime_suspend() can only be executed for 'active'
173 devices (i.e. the PM core will only execute ->runtime_idle() or
174 ->runtime_suspend() for the devices the runtime PM status of which is
177 (3) ->runtime_idle() and ->runtime_suspend() can only be executed for a device
182 (4) ->runtime_resume() can only be executed for 'suspended' devices (i.e. the
183 PM core will only execute ->runtime_resume() for the devices the runtime
189 * If ->runtime_suspend() is about to be executed or there's a pending request
190 to execute it, ->runtime_idle() will not be executed for the same device.
192 * A request to execute or to schedule the execution of ->runtime_suspend()
193 will cancel any pending requests to execute ->runtime_idle() for the same
196 * If ->runtime_resume() is about to be executed or there's a pending request
199 * A request to execute ->runtime_resume() will cancel any pending or
210 - timer used for scheduling (delayed) suspend and autosuspend requests
213 - timer expiration time, in jiffies (if this is different from zero, the
218 - work structure used for queuing up requests (i.e. work items in pm_wq)
221 - wait queue used if any of the helper functions needs to wait for another
225 - lock used for synchronization
228 - the usage counter of the device
231 - the count of 'active' children of the device
234 - if set, the value of child_count is ignored (but still updated)
237 - used for disabling the helper functions (they work normally if this is
242 - if set, there was a fatal error (one of the callbacks returned error code
248 - if set, ->runtime_idle() is being executed
251 - if set, there's a pending request (i.e. a work item queued up into pm_wq)
254 - type of request that's pending (valid if request_pending is set)
257 - set if ->runtime_resume() is about to be run while ->runtime_suspend() is
262 - the runtime PM status of the device; this field's initial value is
267 - the last runtime PM status of the device captured before disabling runtime
271 - if set, indicates that the user space has allowed the device driver to
277 - indicates that the device does not use the runtime PM callbacks (see
282 - indicates that the ->runtime_suspend() and ->runtime_resume() callbacks
286 - indicates that the device's driver supports delayed autosuspend (see
291 - indicates that the PM core should attempt to carry out an autosuspend
295 - the delay time (in milliseconds) to be used for autosuspend
298 - the time (in jiffies) when the pm_runtime_mark_last_busy() helper
300 periods for autosuspend
311 - initialize the device runtime PM fields in 'struct dev_pm_info'
314 - make sure that the runtime PM of the device will be disabled after
318 - execute the subsystem-level idle callback for the device; returns an
319 error code on failure, where -EINPROGRESS means that ->runtime_idle() is
324 - execute the subsystem-level suspend callback for the device; returns 0 on
326 error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt
327 to suspend the device again in future and -EACCES means that
331 - same as pm_runtime_suspend() except that a call to
332 pm_runtime_mark_last_busy() is made and an autosuspend is scheduled for
336 - execute the subsystem-level resume callback for the device; returns 0 on
339 changing from 0 to 1) or error code on failure, where -EAGAIN means it may
341 'power.runtime_error' should be checked additionally, and -EACCES means
346 - run pm_runtime_resume(dev) and if successful, increment the device's
352 - submit a request to execute the subsystem-level idle callback for the
357 - Call pm_runtime_mark_last_busy() and schedule the execution of the
358 subsystem-level suspend callback for the device when the autosuspend delay
361 `int pm_schedule_suspend(struct device *dev, unsigned int delay);`
362 - schedule the execution of the subsystem-level suspend callback for the
363 device in future, where 'delay' is the time to wait before queuing up a
364 suspend work item in pm_wq, in milliseconds (if 'delay' is zero, the work
367 hasn't been scheduled (or queued up if 'delay' is 0); if the execution of
368 ->runtime_suspend() is already scheduled and not yet expired, the new
369 value of 'delay' will be used as the time to wait
372 - submit a request to execute the subsystem-level resume callback for the
378 - increment the device's usage counter
381 - increment the device's usage counter, run pm_request_resume(dev) and
385 - increment the device's usage counter, run pm_runtime_resume(dev) and
393 - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
399 - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
404 - decrement the device's usage counter
407 - decrement the device's usage counter; if the result is 0 then run
411 - set the power.last_busy field to the current time and decrement 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 - set the power.last_busy field to the current time and decrement the
433 - decrement the device's 'power.disable_depth' field; if that field is equal
434 to zero, the runtime PM helper functions can execute subsystem-level
438 - increment the device's 'power.disable_depth' field (if the value of that
439 field was previously zero, this prevents subsystem-level runtime PM
443 necessary to execute the subsystem-level resume callback for the device
447 - check if there's a resume request pending for the device and resume it
451 necessary to execute the subsystem-level resume callback for the device to
455 - set/unset the power.ignore_children flag of the device
458 - clear the device's 'power.runtime_error' flag, set the device's runtime
466 - clear the device's 'power.runtime_error' flag, set the device's runtime
473 - return true if the device's runtime PM status is 'active' or its
477 - return true if the device's runtime PM status is 'suspended' and its
481 - return true if the device's runtime PM status is 'suspended'
484 - set the power.runtime_auto flag for the device and decrease its usage
489 - unset the power.runtime_auto flag for the device and increase its usage
494 - set the power.no_callbacks flag for the device and remove the runtime
499 - set the power.irq_safe flag for the device, causing the runtime-PM
503 - return true if power.irq_safe flag was set for the device, causing
504 the runtime-PM callbacks to be invoked with interrupts off
507 - set the power.last_busy field to the current time
510 - set the power.use_autosuspend flag, enabling autosuspend delays; call
515 - clear the power.use_autosuspend flag, disabling autosuspend delays;
519 `void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);`
520 - set the power.autosuspend_delay value to 'delay' (expressed in
521 milliseconds); if 'delay' is negative then runtime suspends are
529 - calculate the time when the current autosuspend delay period will expire,
530 based on power.last_busy and power.autosuspend_delay; if the delay time
531 is 1000 ms or larger then the expiration time is rounded up to the
532 nearest second; returns 0 if the delay period has already expired or
538 - pm_request_idle()
539 - pm_request_autosuspend()
540 - pm_schedule_suspend()
541 - pm_request_resume()
542 - pm_runtime_get_noresume()
543 - pm_runtime_get()
544 - pm_runtime_put_noidle()
545 - pm_runtime_put()
546 - pm_runtime_put_autosuspend()
547 - __pm_runtime_put_autosuspend()
548 - pm_runtime_enable()
549 - pm_suspend_ignore_children()
550 - pm_runtime_set_active()
551 - pm_runtime_set_suspended()
552 - pm_runtime_suspended()
553 - pm_runtime_mark_last_busy()
554 - pm_runtime_autosuspend_expiration()
559 - pm_runtime_idle()
560 - pm_runtime_suspend()
561 - pm_runtime_autosuspend()
562 - pm_runtime_resume()
563 - pm_runtime_get_sync()
564 - pm_runtime_put_sync()
565 - pm_runtime_put_sync_suspend()
566 - pm_runtime_put_sync_autosuspend()
573 -EAGAIN until pm_runtime_enable() is called for the device.
595 ->probe() callback will likely need to wake it up using one of the PM core's
606 It may be desirable to suspend the device once ->probe() has finished.
608 request to execute the subsystem-level idle callback for the device at that
609 time. A driver that makes use of the runtime autosuspend feature may want to
610 update the last busy mark before returning from ->probe().
621 calling pm_runtime_suspend() from their ->remove() routines, the driver core
624 drivers to make their ->remove() callbacks avoid races with runtime PM directly,
628 Drivers in ->remove() callback should undo the runtime PM changes done
629 in ->probe(). Usually this means calling pm_runtime_disable(),
648 as suspend-to-RAM and suspend-to-disk) interact with each other in a couple of
652 The device may have different wake-up settings for runtime PM and system sleep.
653 For example, remote wake-up may be enabled for runtime suspend but disallowed
655 the subsystem-level system suspend callback is responsible for changing the
656 device's wake-up setting (it may leave that to the device driver's system
665 * The device might need to switch power levels, wake-up settings, etc.
667 * Remote wake-up events might have been lost by the firmware.
682 to be updated to reflect the actual post-system sleep status. The way to do
685 - pm_runtime_disable(dev);
686 - pm_runtime_set_active(dev);
687 - pm_runtime_enable(dev);
690 ->suspend() callback and decrements it after calling the ->resume() callback.
693 following the return of the ->resume() callback, the ->runtime_idle() callback
697 or hardware operation. Instead, all hardware components are put into low-power
711 that the device appears to be runtime-suspended and its state is fine, so it
717 related to hibernation (see Documentation/driver-api/pm/devices.rst for more
725 right before executing the subsystem-level .prepare() callback for it and
727 subsystem-level .suspend() callback for it. In addition to that the PM core
729 device right before executing the subsystem-level .suspend_late() callback
733 every device right after executing the subsystem-level .resume_early()
734 callback and right after executing the subsystem-level .complete() callback
745 - invoke the ->runtime_suspend() callback provided by the driver of this
749 - invoke the ->runtime_resume() callback provided by the driver of this
753 - if the device has not been suspended at run time, invoke the ->suspend()
758 - if pm_runtime_suspended(dev) returns "false", invoke the ->suspend_noirq()
763 - invoke the ->resume() callback provided by the driver of this device and,
767 - invoke the ->resume_noirq() callback provided by the driver of this device
770 - if the device has not been suspended at run time, invoke the ->freeze()
775 - if pm_runtime_suspended(dev) returns "false", invoke the ->freeze_noirq()
780 - if the device has not been suspended at run time, invoke the ->thaw()
785 - if pm_runtime_suspended(dev) returns "false", invoke the ->thaw_noirq()
790 - if the device has not been suspended at run time, invoke the ->poweroff()
795 - if pm_runtime_suspended(dev) returns "false", run the ->poweroff_noirq()
800 - invoke the ->restore() callback provided by the driver of this device and,
804 - invoke the ->restore_noirq() callback provided by the device's driver
807 provide its own callbacks for ->runtime_idle(), ->runtime_suspend(),
808 ->runtime_resume(), ->suspend(), ->suspend_noirq(), ->resume(),
809 ->resume_noirq(), ->freeze(), ->freeze_noirq(), ->thaw(), ->thaw_noirq(),
810 ->poweroff(), ->poweroff_noirq(), ->restore(), ->restore_noirq() in the
811 subsystem-level dev_pm_ops structure.
819 8. "No-Callback" Devices
822 Some "devices" are only logical sub-devices of their parent and cannot be
823 power-managed on their own. (The prototype example is a USB interface. Entire
824 USB devices can go into low-power mode or send wake-up requests, but neither is
826 need of runtime PM callbacks; if the callbacks did exist, ->runtime_suspend()
827 and ->runtime_resume() would always return 0 without doing anything else and
828 ->runtime_idle() would always call pm_runtime_suspend().
834 prevent the non-debugging runtime PM sysfs attributes from being created.
837 ->runtime_idle(), ->runtime_suspend(), or ->runtime_resume() callbacks.
855 9. Autosuspend, or automatically-delayed suspends
859 A device should be put in a low-power state only when there's some reason to
864 the heuristic ends up being non-optimal, it will still prevent devices from
865 "bouncing" too rapidly between low-power and full-power states.
867 The term "autosuspend" is an historical remnant. It doesn't mean that the
878 In order to use autosuspend, subsystems or drivers must call
881 instead of the non-autosuspend counterparts::
888 Drivers may also continue to use the non-autosuspend helper functions; they
889 will behave normally, which means sometimes taking the autosuspend delay into
890 account (see pm_runtime_idle). The autosuspend variants of the functions also
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_put_autosuspend(&foo->dev);
927 unlock(&foo->private_lock);
936 lock(&foo->private_lock);
937 if (foo->num_pending_requests > 0) {
938 ret = -EBUSY;
941 foo->is_suspended = 1;
943 unlock(&foo->private_lock);
951 lock(&foo->private_lock);
953 foo->is_suspended = 0;
954 pm_runtime_mark_last_busy(&foo->dev);
955 if (foo->num_pending_requests > 0)
957 unlock(&foo->private_lock);
961 The important point is that after foo_io_completion() asks for an autosuspend,
969 pm_runtime_autosuspend_expiration() from within the ->runtime_suspend()
971 value then the delay has not yet expired and the callback should return
972 -EAGAIN.