The upstream code doesn't take into account whether the ondemand governor is usable on the platform.
The powertop could suggest ondemand governor even if it is not possible to use it on the platform.
The code was patched and two checks were added. The ondemand governor is additionally not suggested if it is not in the list of available governors (this means there is no kernel support - the driver is either not compiled for the kernel or there is no implementation for the platform) or if the CPU transition time from one frequency to another is above the maximal limit allowed by the ondemand governor.
The ondemand governor is no longer suggested in the tuning suggestions if it cannot be activated on the current kernel / HW.