| What: /sys/devices/.../online |
| Date: April 2013 |
| Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.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. |