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author | Rafael J. Wysocki <rjw@sisk.pl> | 2010-01-23 22:03:22 +0100 |
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committer | Rafael J. Wysocki <rjw@sisk.pl> | 2010-02-26 20:39:09 +0100 |
commit | 971cb7fba0c84dd74c39020f4596b08398f58199 (patch) | |
tree | 752361d6bf5e6a3bef92a3b1709aef79a603a292 /Documentation/ABI | |
parent | 53823639173cc9e9a261f68f4abefe62364b86c6 (diff) | |
download | linux-971cb7fba0c84dd74c39020f4596b08398f58199.tar.bz2 |
PM: Document device power attributes in sysfs
There are sysfs attributes in /sys/devices/.../power/ that haven't
been documented yet in Documentation/ABI/. Document them as
appropriate.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r-- | Documentation/ABI/testing/sysfs-devices-power | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power new file mode 100644 index 000000000000..431bfd7e65c7 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -0,0 +1,53 @@ +What: /sys/devices/.../power/ +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +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@sisk.pl> +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\n" to issue the events; + + "disabled\n" 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 contains "\n". In that cases the user space + cannot modify the contents of this file and the device cannot be + enabled to wake up the system. + +What: /sys/devices/.../power/control +Date: January 2009 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +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\n" to allow the device to be power managed at run time; + + "on\n" 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. |