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kernel/linux-imx6_3.14.28/Documentation/ABI/testing/sysfs-devices-power 9.52 KB
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  What:		/sys/devices/.../power/
  Date:		January 2009
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../power directory contains attributes
  		allowing the user space to check and modify some power
  		management related properties of given device.
  
  What:		/sys/devices/.../power/wakeup
  Date:		January 2009
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../power/wakeup attribute allows the user
  		space to check if the device is enabled to wake up the system
  		from sleep states, such as the memory sleep state (suspend to
  		RAM) and hibernation (suspend to disk), and to enable or disable
  		it to do that as desired.
  
  		Some devices support "wakeup" events, which are hardware signals
  		used to activate the system from a sleep state.  Such devices
  		have one of the following two values for the sysfs power/wakeup
  		file:
  
  		+ "enabled
  " to issue the events;
  		+ "disabled
  " not to do so;
  
  		In that cases the user space can change the setting represented
  		by the contents of this file by writing either "enabled", or
  		"disabled" to it.
  
  		For the devices that are not capable of generating system wakeup
  		events this file is not present.  In that case the device cannot
  		be enabled to wake up the system from sleep states.
  
  What:		/sys/devices/.../power/control
  Date:		January 2009
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../power/control attribute allows the user
  		space to control the run-time power management of the device.
  
  		All devices have one of the following two values for the
  		power/control file:
  
  		+ "auto
  " to allow the device to be power managed at run time;
  		+ "on
  " to prevent the device from being power managed;
  
  		The default for all devices is "auto", which means that they may
  		be subject to automatic power management, depending on their
  		drivers.  Changing this attribute to "on" prevents the driver
  		from power managing the device at run time.  Doing that while
  		the device is suspended causes it to be woken up.
  
  What:		/sys/devices/.../power/async
  Date:		January 2009
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../async attribute allows the user space to
  		enable or diasble the device's suspend and resume callbacks to
  		be executed asynchronously (ie. in separate threads, in parallel
  		with the main suspend/resume thread) during system-wide power
  		transitions (eg. suspend to RAM, hibernation).
  
  		All devices have one of the following two values for the
  		power/async file:
  
  		+ "enabled
  " to permit the asynchronous suspend/resume;
  		+ "disabled
  " to forbid it;
  
  		The value of this attribute may be changed by writing either
  		"enabled", or "disabled" to it.
  
  		It generally is unsafe to permit the asynchronous suspend/resume
  		of a device unless it is certain that all of the PM dependencies
  		of the device are known to the PM core.  However, for some
  		devices this attribute is set to "enabled" by bus type code or
  		device drivers and in that cases it should be safe to leave the
  		default value.
  
  What:		/sys/devices/.../power/wakeup_count
  Date:		September 2010
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_count attribute contains the number
  		of signaled wakeup events associated with the device.  This
  		attribute is read-only.  If the device is not enabled to wake up
  		the system from sleep states, this attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_active_count
  Date:		September 2010
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_active_count attribute contains the
  		number of times the processing of wakeup events associated with
  		the device was completed (at the kernel level).  This attribute
  		is read-only.  If the device is not enabled to wake up the
  		system from sleep states, this attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_abort_count
  Date:		February 2012
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_abort_count attribute contains the
  		number of times the processing of a wakeup event associated with
  		the device might have aborted system transition into a sleep
  		state in progress.  This attribute is read-only.  If the device
  		is not enabled to wake up the system from sleep states, this
  		attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_expire_count
  Date:		February 2012
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_expire_count attribute contains the
  		number of times a wakeup event associated with the device has
  		been reported with a timeout that expired.  This attribute is
  		read-only.  If the device is not enabled to wake up the system
  		from sleep states, this attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_active
  Date:		September 2010
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_active attribute contains either 1,
  		or 0, depending on whether or not a wakeup event associated with
  		the device is being processed (1).  This attribute is read-only.
  		If the device is not enabled to wake up the system from sleep
  		states, this attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_total_time_ms
  Date:		September 2010
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_total_time_ms attribute contains
  		the total time of processing wakeup events associated with the
  		device, in milliseconds.  This attribute is read-only.  If the
  		device is not enabled to wake up the system from sleep states,
  		this attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_max_time_ms
  Date:		September 2010
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_max_time_ms attribute contains
  		the maximum time of processing a single wakeup event associated
  		with the device, in milliseconds.  This attribute is read-only.
  		If the device is not enabled to wake up the system from sleep
  		states, this attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_last_time_ms
  Date:		September 2010
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_last_time_ms attribute contains
  		the value of the monotonic clock corresponding to the time of
  		signaling the last wakeup event associated with the device, in
  		milliseconds.  This attribute is read-only.  If the device is
  		not enabled to wake up the system from sleep states, this
  		attribute is not present.
  
  What:		/sys/devices/.../power/wakeup_prevent_sleep_time_ms
  Date:		February 2012
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../wakeup_prevent_sleep_time_ms attribute
  		contains the total time the device has been preventing
  		opportunistic transitions to sleep states from occurring.
  		This attribute is read-only.  If the device is not enabled to
  		wake up the system from sleep states, this attribute is not
  		present.
  
  What:		/sys/devices/.../power/autosuspend_delay_ms
  Date:		September 2010
  Contact:	Alan Stern <stern@rowland.harvard.edu>
  Description:
  		The /sys/devices/.../power/autosuspend_delay_ms attribute
  		contains the autosuspend delay value (in milliseconds).  Some
  		drivers do not want their device to suspend as soon as it
  		becomes idle at run time; they want the device to remain
  		inactive for a certain minimum period of time first.  That
  		period is called the autosuspend delay.  Negative values will
  		prevent the device from being suspended at run time (similar
  		to writing "on" to the power/control attribute).  Values >=
  		1000 will cause the autosuspend timer expiration to be rounded
  		up to the nearest second.
  
  		Not all drivers support this attribute.  If it isn't supported,
  		attempts to read or write it will yield I/O errors.
  
  What:		/sys/devices/.../power/pm_qos_latency_us
  Date:		March 2012
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../power/pm_qos_resume_latency_us attribute
  		contains the PM QoS resume latency limit for the given device,
  		which is the maximum allowed time it can take to resume the
  		device, after it has been suspended at run time, from a resume
  		request to the moment the device will be ready to process I/O,
  		in microseconds.  If it is equal to 0, however, this means that
  		the PM QoS resume latency may be arbitrary.
  
  		Not all drivers support this attribute.  If it isn't supported,
  		it is not present.
  
  		This attribute has no effect on system-wide suspend/resume and
  		hibernation.
  
  What:		/sys/devices/.../power/pm_qos_no_power_off
  Date:		September 2012
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../power/pm_qos_no_power_off attribute
  		is used for manipulating the PM QoS "no power off" flag.  If
  		set, this flag indicates to the kernel that power should not
  		be removed entirely from the device.
  
  		Not all drivers support this attribute.  If it isn't supported,
  		it is not present.
  
  		This attribute has no effect on system-wide suspend/resume and
  		hibernation.
  
  What:		/sys/devices/.../power/pm_qos_remote_wakeup
  Date:		September 2012
  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
  Description:
  		The /sys/devices/.../power/pm_qos_remote_wakeup attribute
  		is used for manipulating the PM QoS "remote wakeup required"
  		flag.  If set, this flag indicates to the kernel that the
  		device is a source of user events that have to be signaled from
  		its low-power states.
  
  		Not all drivers support this attribute.  If it isn't supported,
  		it is not present.
  
  		This attribute has no effect on system-wide suspend/resume and
  		hibernation.