mirror of
https://github.com/torvalds/linux.git
synced 2024-12-29 14:21:47 +00:00
836aedb141
Make it possible to retrieve the current power state of a device with ACPI power management from user space via sysfs by adding two new attributes, power_state and real_power_state, to the sysfs directory associated with the struct acpi_device object representing the device's ACPI node. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
21 lines
877 B
Plaintext
21 lines
877 B
Plaintext
What: /sys/devices/.../power_state
|
|
Date: January 2013
|
|
Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
Description:
|
|
The /sys/devices/.../power_state attribute is only present for
|
|
device objects representing ACPI device nodes that provide power
|
|
management methods.
|
|
|
|
If present, it contains a string representing the current ACPI
|
|
power state of the given device node. Its possible values,
|
|
"D0", "D1", "D2", "D3hot", and "D3cold", reflect the power state
|
|
names defined by the ACPI specification (ACPI 4 and above).
|
|
|
|
If the device node uses shared ACPI power resources, this state
|
|
determines a list of power resources required not to be turned
|
|
off. However, some power resources needed by the device node in
|
|
higher-power (lower-number) states may also be ON because of
|
|
some other devices using them at the moment.
|
|
|
|
This attribute is read-only.
|