* Ingo Molnar <mingo@xxxxxxx> wrote: > - Create a 'deep idle' mode that suspends. This, if all constraints > are met, is triggered by the scheduler automatically: just like the other > idle modes are triggered currently. This approach fixes the wakeup > races because an incoming wakeup event will set need_resched() and > abort the suspend. > > ( This mode can even use the existing suspend code to bring stuff down, > therefore it also solves the pending timer problem and works even on > PC style x86. ) Note that this does not necessarily have to be implemented as 'execute suspend from the idle task' code: scheduling from the idle task, while can certainly be made to work, is a somewhat recursive concept that we might want to avoid for robustness reasons. Instead, the 'deepest idle' (suspend) method could consist of a wakeup of a kernel thread (or of any of the existing kernel threads such as the migration thread) - which kernel thread then does a race-free suspend: it offlines all but one CPU [on platforms that need that] and then initiates the suspend - but aborts the attempt if there's any sign of wakeup activity. Thanks, Ingo _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
