2006-08-31 05:38:06 +08:00
|
|
|
What: /sys/power/
|
|
|
|
|
Date: August 2006
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2006-08-31 05:38:06 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power directory will contain files that will
|
|
|
|
|
provide a unified interface to the power management
|
|
|
|
|
subsystem.
|
|
|
|
|
|
|
|
|
|
What: /sys/power/state
|
PM / sleep: Introduce command line argument for sleep state enumeration
On some systems the platform doesn't support neither
PM_SUSPEND_MEM nor PM_SUSPEND_STANDBY, so PM_SUSPEND_FREEZE is the
only available system sleep state. However, some user space frameworks
only use the "mem" and (sometimes) "standby" sleep state labels, so
the users of those systems need to modify user space in order to be
able to use system suspend at all and that is not always possible.
For this reason, add a new kernel command line argument,
relative_sleep_states, allowing the users of those systems to change
the way in which the kernel assigns labels to system sleep states.
Namely, for relative_sleep_states=1, the "mem", "standby" and "freeze"
labels will enumerate the available system sleem states from the
deepest to the shallowest, respectively, so that "mem" is always
present in /sys/power/state and the other state strings may or may
not be presend depending on what is supported by the platform.
Update system sleep states documentation to reflect this change.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-26 19:40:59 +08:00
|
|
|
Date: May 2014
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2006-08-31 05:38:06 +08:00
|
|
|
Description:
|
PM / sleep: Introduce command line argument for sleep state enumeration
On some systems the platform doesn't support neither
PM_SUSPEND_MEM nor PM_SUSPEND_STANDBY, so PM_SUSPEND_FREEZE is the
only available system sleep state. However, some user space frameworks
only use the "mem" and (sometimes) "standby" sleep state labels, so
the users of those systems need to modify user space in order to be
able to use system suspend at all and that is not always possible.
For this reason, add a new kernel command line argument,
relative_sleep_states, allowing the users of those systems to change
the way in which the kernel assigns labels to system sleep states.
Namely, for relative_sleep_states=1, the "mem", "standby" and "freeze"
labels will enumerate the available system sleem states from the
deepest to the shallowest, respectively, so that "mem" is always
present in /sys/power/state and the other state strings may or may
not be presend depending on what is supported by the platform.
Update system sleep states documentation to reflect this change.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-26 19:40:59 +08:00
|
|
|
The /sys/power/state file controls system sleep states.
|
|
|
|
|
Reading from this file returns the available sleep state
|
|
|
|
|
labels, which may be "mem", "standby", "freeze" and "disk"
|
|
|
|
|
(hibernation). The meanings of the first three labels depend on
|
|
|
|
|
the relative_sleep_states command line argument as follows:
|
|
|
|
|
1) relative_sleep_states = 1
|
|
|
|
|
"mem", "standby", "freeze" represent non-hibernation sleep
|
|
|
|
|
states from the deepest ("mem", always present) to the
|
|
|
|
|
shallowest ("freeze"). "standby" and "freeze" may or may
|
|
|
|
|
not be present depending on the capabilities of the
|
|
|
|
|
platform. "freeze" can only be present if "standby" is
|
|
|
|
|
present.
|
|
|
|
|
2) relative_sleep_states = 0 (default)
|
|
|
|
|
"mem" - "suspend-to-RAM", present if supported.
|
|
|
|
|
"standby" - "power-on suspend", present if supported.
|
|
|
|
|
"freeze" - "suspend-to-idle", always present.
|
2006-08-31 05:38:06 +08:00
|
|
|
|
|
|
|
|
Writing to this file one of these strings causes the system to
|
PM / sleep: Introduce command line argument for sleep state enumeration
On some systems the platform doesn't support neither
PM_SUSPEND_MEM nor PM_SUSPEND_STANDBY, so PM_SUSPEND_FREEZE is the
only available system sleep state. However, some user space frameworks
only use the "mem" and (sometimes) "standby" sleep state labels, so
the users of those systems need to modify user space in order to be
able to use system suspend at all and that is not always possible.
For this reason, add a new kernel command line argument,
relative_sleep_states, allowing the users of those systems to change
the way in which the kernel assigns labels to system sleep states.
Namely, for relative_sleep_states=1, the "mem", "standby" and "freeze"
labels will enumerate the available system sleem states from the
deepest to the shallowest, respectively, so that "mem" is always
present in /sys/power/state and the other state strings may or may
not be presend depending on what is supported by the platform.
Update system sleep states documentation to reflect this change.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-26 19:40:59 +08:00
|
|
|
transition into the corresponding state, if available. See
|
|
|
|
|
Documentation/power/states.txt for a description of what
|
|
|
|
|
"suspend-to-RAM", "power-on suspend" and "suspend-to-idle" mean.
|
2006-08-31 05:38:06 +08:00
|
|
|
|
|
|
|
|
What: /sys/power/disk
|
2006-11-03 14:07:19 +08:00
|
|
|
Date: September 2006
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2006-08-31 05:38:06 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/disk file controls the operating mode of the
|
|
|
|
|
suspend-to-disk mechanism. Reading from this file returns
|
|
|
|
|
the name of the method by which the system will be put to
|
|
|
|
|
sleep on the next suspend. There are four methods supported:
|
|
|
|
|
'firmware' - means that the memory image will be saved to disk
|
|
|
|
|
by some firmware, in which case we also assume that the
|
|
|
|
|
firmware will handle the system suspend.
|
|
|
|
|
'platform' - the memory image will be saved by the kernel and
|
|
|
|
|
the system will be put to sleep by the platform driver (e.g.
|
|
|
|
|
ACPI or other PM registers).
|
|
|
|
|
'shutdown' - the memory image will be saved by the kernel and
|
|
|
|
|
the system will be powered off.
|
|
|
|
|
'reboot' - the memory image will be saved by the kernel and
|
|
|
|
|
the system will be rebooted.
|
|
|
|
|
|
2006-11-03 14:07:19 +08:00
|
|
|
Additionally, /sys/power/disk can be used to turn on one of the
|
|
|
|
|
two testing modes of the suspend-to-disk mechanism: 'testproc'
|
|
|
|
|
or 'test'. If the suspend-to-disk mechanism is in the
|
|
|
|
|
'testproc' mode, writing 'disk' to /sys/power/state will cause
|
|
|
|
|
the kernel to disable nonboot CPUs and freeze tasks, wait for 5
|
|
|
|
|
seconds, unfreeze tasks and enable nonboot CPUs. If it is in
|
|
|
|
|
the 'test' mode, writing 'disk' to /sys/power/state will cause
|
|
|
|
|
the kernel to disable nonboot CPUs and freeze tasks, shrink
|
|
|
|
|
memory, suspend devices, wait for 5 seconds, resume devices,
|
|
|
|
|
unfreeze tasks and enable nonboot CPUs. Then, we are able to
|
|
|
|
|
look in the log messages and work out, for example, which code
|
|
|
|
|
is being slow and which device drivers are misbehaving.
|
|
|
|
|
|
2006-08-31 05:38:06 +08:00
|
|
|
The suspend-to-disk method may be chosen by writing to this
|
|
|
|
|
file one of the accepted strings:
|
|
|
|
|
|
|
|
|
|
'firmware'
|
|
|
|
|
'platform'
|
|
|
|
|
'shutdown'
|
|
|
|
|
'reboot'
|
2006-11-03 14:07:19 +08:00
|
|
|
'testproc'
|
|
|
|
|
'test'
|
2006-08-31 05:38:06 +08:00
|
|
|
|
|
|
|
|
It will only change to 'firmware' or 'platform' if the system
|
|
|
|
|
supports that.
|
|
|
|
|
|
|
|
|
|
What: /sys/power/image_size
|
|
|
|
|
Date: August 2006
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2006-08-31 05:38:06 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/image_size file controls the size of the image
|
|
|
|
|
created by the suspend-to-disk mechanism. It can be written a
|
|
|
|
|
string representing a non-negative integer that will be used
|
|
|
|
|
as an upper limit of the image size, in bytes. The kernel's
|
|
|
|
|
suspend-to-disk code will do its best to ensure the image size
|
|
|
|
|
will not exceed this number. However, if it turns out to be
|
|
|
|
|
impossible, the kernel will try to suspend anyway using the
|
|
|
|
|
smallest image possible. In particular, if "0" is written to
|
|
|
|
|
this file, the suspend image will be as small as possible.
|
|
|
|
|
|
|
|
|
|
Reading from this file will display the current image size
|
|
|
|
|
limit, which is set to 500 MB by default.
|
|
|
|
|
|
|
|
|
|
What: /sys/power/pm_trace
|
|
|
|
|
Date: August 2006
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2006-08-31 05:38:06 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/pm_trace file controls the code which saves the
|
|
|
|
|
last PM event point in the RTC across reboots, so that you can
|
|
|
|
|
debug a machine that just hangs during suspend (or more
|
|
|
|
|
commonly, during resume). Namely, the RTC is only used to save
|
|
|
|
|
the last PM event point if this file contains '1'. Initially
|
|
|
|
|
it contains '0' which may be changed to '1' by writing a
|
|
|
|
|
string representing a nonzero integer into it.
|
|
|
|
|
|
|
|
|
|
To use this debugging feature you should attempt to suspend
|
|
|
|
|
the machine, then reboot it and run
|
|
|
|
|
|
|
|
|
|
dmesg -s 1000000 | grep 'hash matches'
|
|
|
|
|
|
2010-10-12 06:00:25 +08:00
|
|
|
If you do not get any matches (or they appear to be false
|
|
|
|
|
positives), it is possible that the last PM event point
|
|
|
|
|
referred to a device created by a loadable kernel module. In
|
|
|
|
|
this case cat /sys/power/pm_trace_dev_match (see below) after
|
|
|
|
|
your system is started up and the kernel modules are loaded.
|
|
|
|
|
|
2006-08-31 05:38:06 +08:00
|
|
|
CAUTION: Using it will cause your machine's real-time (CMOS)
|
|
|
|
|
clock to be set to a random invalid time after a resume.
|
2010-01-24 05:25:15 +08:00
|
|
|
|
2010-10-12 06:00:25 +08:00
|
|
|
What; /sys/power/pm_trace_dev_match
|
|
|
|
|
Date: October 2010
|
|
|
|
|
Contact: James Hogan <james@albanarts.com>
|
|
|
|
|
Description:
|
|
|
|
|
The /sys/power/pm_trace_dev_match file contains the name of the
|
|
|
|
|
device associated with the last PM event point saved in the RTC
|
|
|
|
|
across reboots when pm_trace has been used. More precisely it
|
|
|
|
|
contains the list of current devices (including those
|
|
|
|
|
registered by loadable kernel modules since boot) which match
|
|
|
|
|
the device hash in the RTC at boot, with a newline after each
|
|
|
|
|
one.
|
|
|
|
|
|
|
|
|
|
The advantage of this file over the hash matches printed to the
|
|
|
|
|
kernel log (see /sys/power/pm_trace), is that it includes
|
|
|
|
|
devices created after boot by loadable kernel modules.
|
|
|
|
|
|
|
|
|
|
Due to the small hash size necessary to fit in the RTC, it is
|
|
|
|
|
possible that more than one device matches the hash, in which
|
|
|
|
|
case further investigation is required to determine which
|
|
|
|
|
device is causing the problem. Note that genuine RTC clock
|
|
|
|
|
values (such as when pm_trace has not been used), can still
|
|
|
|
|
match a device and output it's name here.
|
|
|
|
|
|
2010-01-24 05:25:15 +08:00
|
|
|
What: /sys/power/pm_async
|
|
|
|
|
Date: January 2009
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2010-01-24 05:25:15 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/pm_async file controls the switch allowing the
|
|
|
|
|
user space to enable or disable asynchronous suspend and resume
|
|
|
|
|
of devices. If enabled, this feature will cause some device
|
|
|
|
|
drivers' suspend and resume callbacks to be executed in parallel
|
|
|
|
|
with each other and with the main suspend thread. It is enabled
|
|
|
|
|
if this file contains "1", which is the default. It may be
|
|
|
|
|
disabled by writing "0" to this file, in which case all devices
|
|
|
|
|
will be suspended and resumed synchronously.
|
PM: Make it possible to avoid races between wakeup and system sleep
One of the arguments during the suspend blockers discussion was that
the mainline kernel didn't contain any mechanisms making it possible
to avoid races between wakeup and system suspend.
Generally, there are two problems in that area. First, if a wakeup
event occurs exactly when /sys/power/state is being written to, it
may be delivered to user space right before the freezer kicks in, so
the user space consumer of the event may not be able to process it
before the system is suspended. Second, if a wakeup event occurs
after user space has been frozen, it is not generally guaranteed that
the ongoing transition of the system into a sleep state will be
aborted.
To address these issues introduce a new global sysfs attribute,
/sys/power/wakeup_count, associated with a running counter of wakeup
events and three helper functions, pm_stay_awake(), pm_relax(), and
pm_wakeup_event(), that may be used by kernel subsystems to control
the behavior of this attribute and to request the PM core to abort
system transitions into a sleep state already in progress.
The /sys/power/wakeup_count file may be read from or written to by
user space. Reads will always succeed (unless interrupted by a
signal) and return the current value of the wakeup events counter.
Writes, however, will only succeed if the written number is equal to
the current value of the wakeup events counter. If a write is
successful, it will cause the kernel to save the current value of the
wakeup events counter and to abort the subsequent system transition
into a sleep state if any wakeup events are reported after the write
has returned.
[The assumption is that before writing to /sys/power/state user space
will first read from /sys/power/wakeup_count. Next, user space
consumers of wakeup events will have a chance to acknowledge or
veto the upcoming system transition to a sleep state. Finally, if
the transition is allowed to proceed, /sys/power/wakeup_count will
be written to and if that succeeds, /sys/power/state will be written
to as well. Still, if any wakeup events are reported to the PM core
by kernel subsystems after that point, the transition will be
aborted.]
Additionally, put a wakeup events counter into struct dev_pm_info and
make these per-device wakeup event counters available via sysfs,
so that it's possible to check the activity of various wakeup event
sources within the kernel.
To illustrate how subsystems can use pm_wakeup_event(), make the
low-level PCI runtime PM wakeup-handling code use it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: markgross <markgross@thegnar.org>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
2010-07-06 04:43:53 +08:00
|
|
|
|
|
|
|
|
What: /sys/power/wakeup_count
|
|
|
|
|
Date: July 2010
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
PM: Make it possible to avoid races between wakeup and system sleep
One of the arguments during the suspend blockers discussion was that
the mainline kernel didn't contain any mechanisms making it possible
to avoid races between wakeup and system suspend.
Generally, there are two problems in that area. First, if a wakeup
event occurs exactly when /sys/power/state is being written to, it
may be delivered to user space right before the freezer kicks in, so
the user space consumer of the event may not be able to process it
before the system is suspended. Second, if a wakeup event occurs
after user space has been frozen, it is not generally guaranteed that
the ongoing transition of the system into a sleep state will be
aborted.
To address these issues introduce a new global sysfs attribute,
/sys/power/wakeup_count, associated with a running counter of wakeup
events and three helper functions, pm_stay_awake(), pm_relax(), and
pm_wakeup_event(), that may be used by kernel subsystems to control
the behavior of this attribute and to request the PM core to abort
system transitions into a sleep state already in progress.
The /sys/power/wakeup_count file may be read from or written to by
user space. Reads will always succeed (unless interrupted by a
signal) and return the current value of the wakeup events counter.
Writes, however, will only succeed if the written number is equal to
the current value of the wakeup events counter. If a write is
successful, it will cause the kernel to save the current value of the
wakeup events counter and to abort the subsequent system transition
into a sleep state if any wakeup events are reported after the write
has returned.
[The assumption is that before writing to /sys/power/state user space
will first read from /sys/power/wakeup_count. Next, user space
consumers of wakeup events will have a chance to acknowledge or
veto the upcoming system transition to a sleep state. Finally, if
the transition is allowed to proceed, /sys/power/wakeup_count will
be written to and if that succeeds, /sys/power/state will be written
to as well. Still, if any wakeup events are reported to the PM core
by kernel subsystems after that point, the transition will be
aborted.]
Additionally, put a wakeup events counter into struct dev_pm_info and
make these per-device wakeup event counters available via sysfs,
so that it's possible to check the activity of various wakeup event
sources within the kernel.
To illustrate how subsystems can use pm_wakeup_event(), make the
low-level PCI runtime PM wakeup-handling code use it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: markgross <markgross@thegnar.org>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
2010-07-06 04:43:53 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/wakeup_count file allows user space to put the
|
|
|
|
|
system into a sleep state while taking into account the
|
|
|
|
|
concurrent arrival of wakeup events. Reading from it returns
|
|
|
|
|
the current number of registered wakeup events and it blocks if
|
|
|
|
|
some wakeup events are being processed at the time the file is
|
|
|
|
|
read from. Writing to it will only succeed if the current
|
|
|
|
|
number of wakeup events is equal to the written value and, if
|
|
|
|
|
successful, will make the kernel abort a subsequent transition
|
|
|
|
|
to a sleep state if any wakeup events are reported after the
|
|
|
|
|
write has returned.
|
2011-05-15 17:38:48 +08:00
|
|
|
|
|
|
|
|
What: /sys/power/reserved_size
|
|
|
|
|
Date: May 2011
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2011-05-15 17:38:48 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/reserved_size file allows user space to control
|
|
|
|
|
the amount of memory reserved for allocations made by device
|
|
|
|
|
drivers during the "device freeze" stage of hibernation. It can
|
|
|
|
|
be written a string representing a non-negative integer that
|
|
|
|
|
will be used as the amount of memory to reserve for allocations
|
|
|
|
|
made by device drivers' "freeze" callbacks, in bytes.
|
|
|
|
|
|
|
|
|
|
Reading from this file will display the current value, which is
|
|
|
|
|
set to 1 MB by default.
|
2012-04-30 04:53:22 +08:00
|
|
|
|
|
|
|
|
What: /sys/power/autosleep
|
|
|
|
|
Date: April 2012
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
2012-04-30 04:53:22 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/autosleep file can be written one of the strings
|
|
|
|
|
returned by reads from /sys/power/state. If that happens, a
|
|
|
|
|
work item attempting to trigger a transition of the system to
|
|
|
|
|
the sleep state represented by that string is queued up. This
|
|
|
|
|
attempt will only succeed if there are no active wakeup sources
|
|
|
|
|
in the system at that time. After every execution, regardless
|
|
|
|
|
of whether or not the attempt to put the system to sleep has
|
|
|
|
|
succeeded, the work item requeues itself until user space
|
|
|
|
|
writes "off" to /sys/power/autosleep.
|
|
|
|
|
|
|
|
|
|
Reading from this file causes the last string successfully
|
|
|
|
|
written to it to be returned.
|
PM / Sleep: Add user space interface for manipulating wakeup sources, v3
Android allows user space to manipulate wakelocks using two
sysfs file located in /sys/power/, wake_lock and wake_unlock.
Writing a wakelock name and optionally a timeout to the wake_lock
file causes the wakelock whose name was written to be acquired (it
is created before is necessary), optionally with the given timeout.
Writing the name of a wakelock to wake_unlock causes that wakelock
to be released.
Implement an analogous interface for user space using wakeup sources.
Add the /sys/power/wake_lock and /sys/power/wake_unlock files
allowing user space to create, activate and deactivate wakeup
sources, such that writing a name and optionally a timeout to
wake_lock causes the wakeup source of that name to be activated,
optionally with the given timeout. If that wakeup source doesn't
exist, it will be created and then activated. Writing a name to
wake_unlock causes the wakeup source of that name, if there is one,
to be deactivated. Wakeup sources created with the help of
wake_lock that haven't been used for more than 5 minutes are garbage
collected and destroyed. Moreover, there can be only WL_NUMBER_LIMIT
wakeup sources created with the help of wake_lock present at a time.
The data type used to track wakeup sources created by user space is
called "struct wakelock" to indicate the origins of this feature.
This version of the patch includes an rbtree manipulation fix from John Stultz.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NeilBrown <neilb@suse.de>
2012-04-30 04:53:42 +08:00
|
|
|
|
|
|
|
|
What: /sys/power/wake_lock
|
|
|
|
|
Date: February 2012
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
PM / Sleep: Add user space interface for manipulating wakeup sources, v3
Android allows user space to manipulate wakelocks using two
sysfs file located in /sys/power/, wake_lock and wake_unlock.
Writing a wakelock name and optionally a timeout to the wake_lock
file causes the wakelock whose name was written to be acquired (it
is created before is necessary), optionally with the given timeout.
Writing the name of a wakelock to wake_unlock causes that wakelock
to be released.
Implement an analogous interface for user space using wakeup sources.
Add the /sys/power/wake_lock and /sys/power/wake_unlock files
allowing user space to create, activate and deactivate wakeup
sources, such that writing a name and optionally a timeout to
wake_lock causes the wakeup source of that name to be activated,
optionally with the given timeout. If that wakeup source doesn't
exist, it will be created and then activated. Writing a name to
wake_unlock causes the wakeup source of that name, if there is one,
to be deactivated. Wakeup sources created with the help of
wake_lock that haven't been used for more than 5 minutes are garbage
collected and destroyed. Moreover, there can be only WL_NUMBER_LIMIT
wakeup sources created with the help of wake_lock present at a time.
The data type used to track wakeup sources created by user space is
called "struct wakelock" to indicate the origins of this feature.
This version of the patch includes an rbtree manipulation fix from John Stultz.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NeilBrown <neilb@suse.de>
2012-04-30 04:53:42 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/wake_lock file allows user space to create
|
|
|
|
|
wakeup source objects and activate them on demand (if one of
|
|
|
|
|
those wakeup sources is active, reads from the
|
|
|
|
|
/sys/power/wakeup_count file block or return false). When a
|
|
|
|
|
string without white space is written to /sys/power/wake_lock,
|
|
|
|
|
it will be assumed to represent a wakeup source name. If there
|
|
|
|
|
is a wakeup source object with that name, it will be activated
|
|
|
|
|
(unless active already). Otherwise, a new wakeup source object
|
|
|
|
|
will be registered, assigned the given name and activated.
|
|
|
|
|
If a string written to /sys/power/wake_lock contains white
|
|
|
|
|
space, the part of the string preceding the white space will be
|
|
|
|
|
regarded as a wakeup source name and handled as descrived above.
|
|
|
|
|
The other part of the string will be regarded as a timeout (in
|
|
|
|
|
nanoseconds) such that the wakeup source will be automatically
|
|
|
|
|
deactivated after it has expired. The timeout, if present, is
|
|
|
|
|
set regardless of the current state of the wakeup source object
|
|
|
|
|
in question.
|
|
|
|
|
|
|
|
|
|
Reads from this file return a string consisting of the names of
|
|
|
|
|
wakeup sources created with the help of it that are active at
|
|
|
|
|
the moment, separated with spaces.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
What: /sys/power/wake_unlock
|
|
|
|
|
Date: February 2012
|
2013-10-09 07:47:53 +08:00
|
|
|
Contact: Rafael J. Wysocki <rjw@rjwysocki.net>
|
PM / Sleep: Add user space interface for manipulating wakeup sources, v3
Android allows user space to manipulate wakelocks using two
sysfs file located in /sys/power/, wake_lock and wake_unlock.
Writing a wakelock name and optionally a timeout to the wake_lock
file causes the wakelock whose name was written to be acquired (it
is created before is necessary), optionally with the given timeout.
Writing the name of a wakelock to wake_unlock causes that wakelock
to be released.
Implement an analogous interface for user space using wakeup sources.
Add the /sys/power/wake_lock and /sys/power/wake_unlock files
allowing user space to create, activate and deactivate wakeup
sources, such that writing a name and optionally a timeout to
wake_lock causes the wakeup source of that name to be activated,
optionally with the given timeout. If that wakeup source doesn't
exist, it will be created and then activated. Writing a name to
wake_unlock causes the wakeup source of that name, if there is one,
to be deactivated. Wakeup sources created with the help of
wake_lock that haven't been used for more than 5 minutes are garbage
collected and destroyed. Moreover, there can be only WL_NUMBER_LIMIT
wakeup sources created with the help of wake_lock present at a time.
The data type used to track wakeup sources created by user space is
called "struct wakelock" to indicate the origins of this feature.
This version of the patch includes an rbtree manipulation fix from John Stultz.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NeilBrown <neilb@suse.de>
2012-04-30 04:53:42 +08:00
|
|
|
Description:
|
|
|
|
|
The /sys/power/wake_unlock file allows user space to deactivate
|
|
|
|
|
wakeup sources created with the help of /sys/power/wake_lock.
|
|
|
|
|
When a string is written to /sys/power/wake_unlock, it will be
|
|
|
|
|
assumed to represent the name of a wakeup source to deactivate.
|
|
|
|
|
If a wakeup source object of that name exists and is active at
|
|
|
|
|
the moment, it will be deactivated.
|
|
|
|
|
|
|
|
|
|
Reads from this file return a string consisting of the names of
|
|
|
|
|
wakeup sources created with the help of /sys/power/wake_lock
|
|
|
|
|
that are inactive at the moment, separated with spaces.
|
2012-06-20 04:23:33 +08:00
|
|
|
|
|
|
|
|
What: /sys/power/pm_print_times
|
|
|
|
|
Date: May 2012
|
|
|
|
|
Contact: Sameer Nanda <snanda@chromium.org>
|
|
|
|
|
Description:
|
|
|
|
|
The /sys/power/pm_print_times file allows user space to
|
|
|
|
|
control whether the time taken by devices to suspend and
|
|
|
|
|
resume is printed. These prints are useful for hunting down
|
|
|
|
|
devices that take too long to suspend or resume.
|
|
|
|
|
|
|
|
|
|
Writing a "1" enables this printing while writing a "0"
|
|
|
|
|
disables it. The default value is "0". Reading from this file
|
|
|
|
|
will display the current value.
|