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| author | Rafael J. Wysocki <rjw@sisk.pl> | 2010-01-23 22:25:23 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rjw@sisk.pl> | 2010-02-26 20:39:10 +0100 |
| commit | 5a2eb8585f3b38e01e30aacaa8b985a1520a993d (patch) | |
| tree | 471b33cc48cf48ed491e8b3f2934bfb3fa9e81e1 /Documentation/ABI/testing/sysfs-devices-power | |
| parent | 0e06b4a891c6a108412fe24b4500f499da2cf8a1 (diff) | |
| download | lwn-5a2eb8585f3b38e01e30aacaa8b985a1520a993d.tar.gz lwn-5a2eb8585f3b38e01e30aacaa8b985a1520a993d.zip | |
PM: Add facility for advanced testing of async suspend/resume
Add configuration switch CONFIG_PM_ADVANCED_DEBUG for compiling in
extra PM debugging/testing code allowing one to access some
PM-related attributes of devices from the user space via sysfs.
If CONFIG_PM_ADVANCED_DEBUG is set, add sysfs attribute power/async
for every device allowing the user space to access the device's
power.async_suspend flag and modify it, if desired.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-power')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-power | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 431bfd7e65c7..6123c523bfd7 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -51,3 +51,29 @@ Description: 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@sisk.pl> +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\n" to permit the asynchronous suspend/resume; + + "disabled\n" 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. |