A mobile processor has several unoccupied states that it can enter into to save energy when it hasn’t done anything. States that save more energy usually need more time to enter and exit. These two source files describe two different methods for choosing the best input state.
If a too deep state is entered immediately, it will be woken up too soon to warrant a higher transition cost. Conversely, if too small a condition is selected, then potential energy savings will be lost.
The staircase regulator first enters the lightest state and will only move to the next deeper state if the sleep was long enough, as determined by a certain measure. First, he will sleep in state 1, then 2, then 3, etc., until either the deepest available state is reached, or the CPU reboots after too short a time. In this case, the governor will choose the state next time.
The menu slider does not necessarily follow this progression, but can immediately go into a deeper state if it determines that it can be useful.