Lines Matching full:runtime
2 Runtime Power Management Framework for I/O Devices
14 Support for runtime power management (runtime PM) of I/O devices is provided
19 used for queuing all work items related to runtime PM, because this allows
24 * A number of runtime PM fields in the 'power' member of 'struct device' (which
26 be used for synchronizing runtime PM operations with one another.
28 * Three device runtime PM callbacks in 'struct dev_pm_ops' (defined in
31 * A set of helper functions defined in drivers/base/power/runtime.c that can be
32 used for carrying out runtime PM operations in such a way that the
36 The runtime PM callbacks present in 'struct dev_pm_ops', the device runtime PM
38 runtime PM are described below.
40 2. Device Runtime PM Callbacks
43 There are three device runtime PM callbacks defined in 'struct dev_pm_ops'::
98 RAM until the appropriate resume callback is executed for it. The runtime
102 * If the suspend callback returns -EBUSY or -EAGAIN, the device's runtime PM
131 I/O operations as needed. The runtime PM status of the device is then
155 0, then the PM core will attempt to carry out a runtime suspend of the device,
164 that the following constraints are met with respect to runtime PM callbacks for
176 ->runtime_suspend() for the devices the runtime PM status of which is
185 PM core will only execute ->runtime_resume() for the devices the runtime
205 3. Runtime PM Device Fields
208 The following device runtime PM fields are present in 'struct dev_pm_info', as
240 equal to zero); the initial value of it is 1 (i.e. runtime PM 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
279 - indicates that the device does not use the runtime PM callbacks (see
306 4. Runtime PM Device Helper Functions
309 The following runtime PM helper functions are defined in
310 drivers/base/power/runtime.c and include/linux/pm_runtime.h:
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
327 success, 1 if the device's runtime PM status was already 'suspended', or
340 success, 1 if the device's runtime PM status is already 'active' (also if
367 runtime status was already 'suspended', or error code if the request
375 success, 1 if the device's runtime PM status was already 'active', or
395 runtime PM status is RPM_ACTIVE and the runtime PM usage counter is
401 runtime PM status is RPM_ACTIVE, and either ign_usage_count is true
430 to zero, the runtime PM helper functions can execute subsystem-level
435 field was previously zero, this prevents subsystem-level runtime PM
437 pending runtime PM operations on the device are either completed or
444 (synchronously) in that case, cancel any other pending runtime PM requests
445 regarding it and wait for all runtime PM operations on it in progress to
454 - clear the device's 'power.runtime_error' flag, set the device's runtime
462 - clear the device's 'power.runtime_error' flag, set the device's runtime
469 - return true if the device's runtime PM status is 'active' or its
473 - return true if the device's runtime PM status is 'suspended' and its
477 - return true if the device's runtime PM status is 'suspended'
490 - set the power.no_callbacks flag for the device and remove the runtime
495 - set the power.irq_safe flag for the device, causing the runtime-PM
500 the runtime-PM callbacks to be invoked with interrupts off
517 milliseconds); if 'delay' is negative then runtime suspends are
563 5. Runtime PM Initialization, Device Probing and Removal
566 Initially, the runtime PM is disabled for all devices, which means that the
567 majority of the runtime PM helper functions described in Section 4 will return
570 In addition to that, the initial runtime PM status of all devices is
573 runtime PM status must be changed to 'active', with the help of
576 However, if the device has a parent and the parent's runtime PM is enabled,
581 runtime PM is still disabled (i.e. pm_runtime_enable() hasn't been called for
584 should be called for it too as soon as reasonably possible or its runtime PM
588 If the default initial runtime PM status of the device (i.e. 'suspended')
592 should be used. Of course, for this purpose the device's runtime PM has to be
604 time. A driver that makes use of the runtime autosuspend feature may want to
607 Moreover, the driver core prevents runtime PM callbacks from racing with the bus
610 runtime PM functionality. It does so by calling pm_runtime_get_sync() before
619 drivers to make their ->remove() callbacks avoid races with runtime PM directly,
623 Drivers in ->remove() callback should undo the runtime PM changes done
631 runtime power management of the device until the user space turns it on.
632 Namely, during the initialization the driver can make sure that the runtime PM
639 6. Runtime PM and System Sleep
642 Runtime PM and system sleep (i.e., system suspend and hibernation, also known
647 The device may have different wake-up settings for runtime PM and system sleep.
648 For example, remote wake-up may be enabled for runtime suspend but disallowed
654 or other settings for runtime suspend and system sleep.
673 likely it would need a runtime resume in the near future anyway.
676 brought back to full power during resume, then its runtime PM status will have
684 The PM core always increments the runtime usage counter before calling the
686 Hence disabling runtime PM temporarily like this will not cause any runtime
706 that the device appears to be runtime-suspended and its state is fine, so it
707 may be left in runtime suspend provided that all of its descendants are also
708 left in runtime suspend. If that happens, the PM core will not execute any
716 the runtime PM and system suspend/resume (and hibernation) callbacks by carrying
758 if successful, change the device's runtime PM status to 'active'
795 if successful, change the device's runtime PM status to 'active'
808 poweroff and runtime suspend callback, and similarly for system resume, thaw,
809 restore, and runtime resume, can achieve this with the help of the
820 need of runtime PM callbacks; if the callbacks did exist, ->runtime_suspend()
828 prevent the non-debugging runtime PM sysfs attributes from being created.
836 or driver about runtime power changes. Instead, the driver for the device's
842 the runtime PM callbacks needs to be implemented, a platform dependent PM
845 in subsystems/drivers, the PM core allows runtime PM callbacks to be
857 at runtime until they have been inactive for some minimum period. Even when
863 the appropriate PM routines); rather it means that runtime suspends will