1*4882a593SmuzhiyunWhat: /sys/devices/.../power_state 2*4882a593SmuzhiyunDate: January 2013 3*4882a593SmuzhiyunContact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 4*4882a593SmuzhiyunDescription: 5*4882a593Smuzhiyun The /sys/devices/.../power_state attribute is only present for 6*4882a593Smuzhiyun device objects representing ACPI device nodes that provide power 7*4882a593Smuzhiyun management methods. 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun If present, it contains a string representing the current ACPI 10*4882a593Smuzhiyun power state of the given device node. Its possible values, 11*4882a593Smuzhiyun "D0", "D1", "D2", "D3hot", and "D3cold", reflect the power state 12*4882a593Smuzhiyun names defined by the ACPI specification (ACPI 4 and above). 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun If the device node uses shared ACPI power resources, this state 15*4882a593Smuzhiyun determines a list of power resources required not to be turned 16*4882a593Smuzhiyun off. However, some power resources needed by the device node in 17*4882a593Smuzhiyun higher-power (lower-number) states may also be ON because of 18*4882a593Smuzhiyun some other devices using them at the moment. 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun This attribute is read-only. 21