| Rafael J. Wysocki | 836aedb | 2013-01-24 12:49:59 +0100 | [diff] [blame] | 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. |