18c2ecf20Sopenharmony_ciWhat: /sys/devices/.../online 28c2ecf20Sopenharmony_ciDate: April 2013 38c2ecf20Sopenharmony_ciContact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 48c2ecf20Sopenharmony_ciDescription: 58c2ecf20Sopenharmony_ci The /sys/devices/.../online attribute is only present for 68c2ecf20Sopenharmony_ci devices whose bus types provide .online() and .offline() 78c2ecf20Sopenharmony_ci callbacks. The number read from it (0 or 1) reflects the value 88c2ecf20Sopenharmony_ci of the device's 'offline' field. If that number is 1 and '0' 98c2ecf20Sopenharmony_ci (or 'n', or 'N') is written to this file, the device bus type's 108c2ecf20Sopenharmony_ci .offline() callback is executed for the device and (if 118c2ecf20Sopenharmony_ci successful) its 'offline' field is updated accordingly. In 128c2ecf20Sopenharmony_ci turn, if that number is 0 and '1' (or 'y', or 'Y') is written to 138c2ecf20Sopenharmony_ci this file, the device bus type's .online() callback is executed 148c2ecf20Sopenharmony_ci for the device and (if successful) its 'offline' field is 158c2ecf20Sopenharmony_ci updated as appropriate. 168c2ecf20Sopenharmony_ci 178c2ecf20Sopenharmony_ci After a successful execution of the bus type's .offline() 188c2ecf20Sopenharmony_ci callback the device cannot be used for any purpose until either 198c2ecf20Sopenharmony_ci it is removed (i.e. device_del() is called for it), or its bus 208c2ecf20Sopenharmony_ci type's .online() is exeucted successfully. 21