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linux-next/include/linux/pm_runtime.h
Rafael J. Wysocki aae4518b31 PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily 
Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to
resume all runtime-suspended devices during system suspend, mostly
because those devices may need to be reprogrammed due to different
wakeup settings for system sleep and for runtime PM.

For some devices, though, it's OK to remain in runtime suspend
throughout a complete system suspend/resume cycle (if the device was in
runtime suspend at the start of the cycle).  We would like to do this
whenever possible, to avoid the overhead of extra power-up and power-down
events.

However, problems may arise because the device's descendants may require
it to be at full power at various points during the cycle.  Therefore the
most straightforward way to do this safely is if the device and all its
descendants can remain runtime suspended until the complete stage of
system resume.

To this end, introduce a new device PM flag, power.direct_complete
and modify the PM core to use that flag as follows.

If the ->prepare() callback of a device returns a positive number,
the PM core will regard that as an indication that it may leave the
device runtime-suspended.  It will then check if the system power
transition in progress is a suspend (and not hibernation in particular)
and if the device is, indeed, runtime-suspended.  In that case, the PM
core will set the device's power.direct_complete flag.  Otherwise it
will clear power.direct_complete for the device and it also will later
clear it for the device's parent (if there's one).

Next, the PM core will not invoke the ->suspend() ->suspend_late(),
->suspend_irq(), ->resume_irq(), ->resume_early(), or ->resume()
callbacks for all devices having power.direct_complete set.  It
will invoke their ->complete() callbacks, however, and those
callbacks are then responsible for resuming the devices as
appropriate, if necessary.  For example, in some cases they may
need to queue up runtime resume requests for the devices using
pm_request_resume().

Changelog partly based on an Alan Stern's description of the idea
(http://marc.info/?l=linux-pm&m=139940466625569&w=2).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
2014-05-16 23:15:44 +02:00

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/*
* pm_runtime.h - Device run-time power management helper functions.
*
* Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*/
#ifndef _LINUX_PM_RUNTIME_H
#define _LINUX_PM_RUNTIME_H
#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/pm.h>
#include <linux/jiffies.h>
/* Runtime PM flag argument bits */
#define RPM_ASYNC 0x01 /* Request is asynchronous */
#define RPM_NOWAIT 0x02 /* Don't wait for concurrent
state change */
#define RPM_GET_PUT 0x04 /* Increment/decrement the
usage_count */
#define RPM_AUTO 0x08 /* Use autosuspend_delay */
#ifdef CONFIG_PM
extern int pm_generic_runtime_suspend(struct device *dev);
extern int pm_generic_runtime_resume(struct device *dev);
extern int pm_runtime_force_suspend(struct device *dev);
extern int pm_runtime_force_resume(struct device *dev);
#else
static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
static inline int pm_runtime_force_suspend(struct device *dev) { return 0; }
static inline int pm_runtime_force_resume(struct device *dev) { return 0; }
#endif
#ifdef CONFIG_PM_RUNTIME
extern struct workqueue_struct *pm_wq;
extern int __pm_runtime_idle(struct device *dev, int rpmflags);
extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
extern int __pm_runtime_resume(struct device *dev, int rpmflags);
extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
extern int pm_runtime_barrier(struct device *dev);
extern void pm_runtime_enable(struct device *dev);
extern void __pm_runtime_disable(struct device *dev, bool check_resume);
extern void pm_runtime_allow(struct device *dev);
extern void pm_runtime_forbid(struct device *dev);
extern void pm_runtime_no_callbacks(struct device *dev);
extern void pm_runtime_irq_safe(struct device *dev);
extern void __pm_runtime_use_autosuspend(struct device *dev, bool use);
extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);
extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev);
extern void pm_runtime_update_max_time_suspended(struct device *dev,
s64 delta_ns);
extern void pm_runtime_set_memalloc_noio(struct device *dev, bool enable);
static inline bool pm_children_suspended(struct device *dev)
{
return dev->power.ignore_children
|| !atomic_read(&dev->power.child_count);
}
static inline void pm_runtime_get_noresume(struct device *dev)
{
atomic_inc(&dev->power.usage_count);
}
static inline void pm_runtime_put_noidle(struct device *dev)
{
atomic_add_unless(&dev->power.usage_count, -1, 0);
}
static inline bool device_run_wake(struct device *dev)
{
return dev->power.run_wake;
}
static inline void device_set_run_wake(struct device *dev, bool enable)
{
dev->power.run_wake = enable;
}
static inline bool pm_runtime_suspended(struct device *dev)
{
return dev->power.runtime_status == RPM_SUSPENDED
&& !dev->power.disable_depth;
}
static inline bool pm_runtime_active(struct device *dev)
{
return dev->power.runtime_status == RPM_ACTIVE
|| dev->power.disable_depth;
}
static inline bool pm_runtime_status_suspended(struct device *dev)
{
return dev->power.runtime_status == RPM_SUSPENDED;
}
static inline bool pm_runtime_suspended_if_enabled(struct device *dev)
{
return pm_runtime_status_suspended(dev) && dev->power.disable_depth == 1;
}
static inline bool pm_runtime_enabled(struct device *dev)
{
return !dev->power.disable_depth;
}
static inline bool pm_runtime_callbacks_present(struct device *dev)
{
return !dev->power.no_callbacks;
}
static inline void pm_runtime_mark_last_busy(struct device *dev)
{
ACCESS_ONCE(dev->power.last_busy) = jiffies;
}
#else /* !CONFIG_PM_RUNTIME */
static inline int __pm_runtime_idle(struct device *dev, int rpmflags)
{
return -ENOSYS;
}
static inline int __pm_runtime_suspend(struct device *dev, int rpmflags)
{
return -ENOSYS;
}
static inline int __pm_runtime_resume(struct device *dev, int rpmflags)
{
return 1;
}
static inline int pm_schedule_suspend(struct device *dev, unsigned int delay)
{
return -ENOSYS;
}
static inline int __pm_runtime_set_status(struct device *dev,
unsigned int status) { return 0; }
static inline int pm_runtime_barrier(struct device *dev) { return 0; }
static inline void pm_runtime_enable(struct device *dev) {}
static inline void __pm_runtime_disable(struct device *dev, bool c) {}
static inline void pm_runtime_allow(struct device *dev) {}
static inline void pm_runtime_forbid(struct device *dev) {}
static inline bool pm_children_suspended(struct device *dev) { return false; }
static inline void pm_runtime_get_noresume(struct device *dev) {}
static inline void pm_runtime_put_noidle(struct device *dev) {}
static inline bool device_run_wake(struct device *dev) { return false; }
static inline void device_set_run_wake(struct device *dev, bool enable) {}
static inline bool pm_runtime_suspended(struct device *dev) { return false; }
static inline bool pm_runtime_active(struct device *dev) { return true; }
static inline bool pm_runtime_status_suspended(struct device *dev) { return false; }
static inline bool pm_runtime_suspended_if_enabled(struct device *dev) { return false; }
static inline bool pm_runtime_enabled(struct device *dev) { return false; }
static inline void pm_runtime_no_callbacks(struct device *dev) {}
static inline void pm_runtime_irq_safe(struct device *dev) {}
static inline bool pm_runtime_callbacks_present(struct device *dev) { return false; }
static inline void pm_runtime_mark_last_busy(struct device *dev) {}
static inline void __pm_runtime_use_autosuspend(struct device *dev,
bool use) {}
static inline void pm_runtime_set_autosuspend_delay(struct device *dev,
int delay) {}
static inline unsigned long pm_runtime_autosuspend_expiration(
struct device *dev) { return 0; }
static inline void pm_runtime_set_memalloc_noio(struct device *dev,
bool enable){}
#endif /* !CONFIG_PM_RUNTIME */
static inline int pm_runtime_idle(struct device *dev)
{
return __pm_runtime_idle(dev, 0);
}
static inline int pm_runtime_suspend(struct device *dev)
{
return __pm_runtime_suspend(dev, 0);
}
static inline int pm_runtime_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_AUTO);
}
static inline int pm_runtime_resume(struct device *dev)
{
return __pm_runtime_resume(dev, 0);
}
static inline int pm_request_idle(struct device *dev)
{
return __pm_runtime_idle(dev, RPM_ASYNC);
}
static inline int pm_request_resume(struct device *dev)
{
return __pm_runtime_resume(dev, RPM_ASYNC);
}
static inline int pm_request_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_ASYNC | RPM_AUTO);
}
static inline int pm_runtime_get(struct device *dev)
{
return __pm_runtime_resume(dev, RPM_GET_PUT | RPM_ASYNC);
}
static inline int pm_runtime_get_sync(struct device *dev)
{
return __pm_runtime_resume(dev, RPM_GET_PUT);
}
static inline int pm_runtime_put(struct device *dev)
{
return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC);
}
static inline int pm_runtime_put_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev,
RPM_GET_PUT | RPM_ASYNC | RPM_AUTO);
}
static inline int pm_runtime_put_sync(struct device *dev)
{
return __pm_runtime_idle(dev, RPM_GET_PUT);
}
static inline int pm_runtime_put_sync_suspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_GET_PUT);
}
static inline int pm_runtime_put_sync_autosuspend(struct device *dev)
{
return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO);
}
static inline int pm_runtime_set_active(struct device *dev)
{
return __pm_runtime_set_status(dev, RPM_ACTIVE);
}
static inline void pm_runtime_set_suspended(struct device *dev)
{
__pm_runtime_set_status(dev, RPM_SUSPENDED);
}
static inline void pm_runtime_disable(struct device *dev)
{
__pm_runtime_disable(dev, true);
}
static inline void pm_runtime_use_autosuspend(struct device *dev)
{
__pm_runtime_use_autosuspend(dev, true);
}
static inline void pm_runtime_dont_use_autosuspend(struct device *dev)
{
__pm_runtime_use_autosuspend(dev, false);
}
#endif
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