What: /sys/devices/.../onlineDate: April 2013Contact: Rafael J. Wysocki <email@example.com>Description: The /sys/devices/.../online attribute is only present for devices whose bus types provide .online() and .offline() callbacks. The number read from it (0 or 1) reflects the value of the device's 'offline' field. If that number is 1 and '0' (or 'n', or 'N') is written to this file, the device bus type's .offline() callback is executed for the device and (if successful) its 'offline' field is updated accordingly. In turn, if that number is 0 and '1' (or 'y', or 'Y') is written to this file, the device bus type's .online() callback is executed for the device and (if successful) its 'offline' field is updated as appropriate. After a successful execution of the bus type's .offline() callback the device cannot be used for any purpose until either it is removed (i.e. device_del() is called for it), or its bus type's .online() is exeucted successfully.