Documentation/ABI/testing/sysfs-devices-power_state

   1 What:           /sys/devices/.../power_state
   2 Date:           January 2013
   3 Contact:        Rafael J. Wysocki <rafael.j.wysocki@intel.com>
   4 Description:
   5                 The /sys/devices/.../power_state attribute is only present for
   6                 device objects representing ACPI device nodes that provide power
   7                 management methods.
   8
   9                 If present, it contains a string representing the current ACPI
  10                 power state of the given device node.  Its possible values,
  11                 "D0", "D1", "D2", "D3hot", and "D3cold", reflect the power state
  12                 names defined by the ACPI specification (ACPI 4 and above).
  13
  14                 If the device node uses shared ACPI power resources, this state
  15                 determines a list of power resources required not to be turned
  16                 off.  However, some power resources needed by the device node in
  17                 higher-power (lower-number) states may also be ON because of
  18                 some other devices using them at the moment.
  19
  20                 This attribute is read-only.