7.5. OSPM usage of _PTS, _TTS, and _WAK

OSPM will invoke _PTS, _TTS,and _WAK in the following order:

  1. OSPM decides (through a policy scheme) to place the system into a sleeping state StepNumList-1 OSPM decides (through a policy scheme) to place the system into a sleeping state

  2. _TTS(Sx) is run, where Sx is the desired sleep state to enter

  3. OSPM notifies all native device drivers of the sleep state transition

  4. _PTS is run

  5. OSPM readies system for the sleep state transition

  6. OSPM writes the sleep vector and the system enters the specified Sx sleep state

  7. System Wakes up

  8. OSPM readies system for the return from the sleep state transition

  9. _WAK is run

  10. OSPM notifies all native device drivers of the return from the sleep state transition

  11. _TTS(0) is run to indicate the return to the S0 state

../_images/Power_and_Performance_Mgmt-2.png

Fig. 7.1 Working / Sleeping State object evaluation flow