1d8012181SPatrick VentureThermalControllers and FanControllers are derived objects from a common PID 2d8012181SPatrick VentureController object. The design implemented in this structure is a facsimile of 3d8012181SPatrick Venturewhat was published in the Chrome OS source. 4d8012181SPatrick Venture 5d8012181SPatrick VentureOne has any number of ThermalControllers that run through a PID step to 6*7280e27eSPatrick Venturegenerate a setpoint RPM to reach its thermal setpoint. The maximum output 7d8012181SPatrick Venturefrom the set of ThermalControllers is taken as the input to all the 8d8012181SPatrick VentureFanController PID loops. 9d8012181SPatrick Venture 10d8012181SPatrick VentureEach group of these controllers is managed within a zone. A PIDZone object 11d8012181SPatrick Venturehelps manage them by providing a sensor value cache and overall execution. 12