On Mon, 28 Jun 2010, Rafael J. Wysocki wrote: > +/* > + * The functions below use the observation that each wakeup event starts a > + * period in which the system should not be suspended. The moment this period > + * will end depends on how the wakeup event is going to be processed after being > + * detected and all of the possible cases can be divided into two distinct > + * groups. > + * > + * First, a wakeup event may be detected by the same functional unit that will > + * carry out the entire processing of it and possibly will pass it to user space > + * for further processing. In that case the functional unit that has detected > + * the event may later "close" the "no suspend" period associated with it > + * directly as soon as it has been dealt with. The pair of pm_stay_awake() and > + * pm_relax(), balanced with each other, is supposed to be used in such > + * situations. > + * > + * Second, a wakeup event may be detected by one functional unit and processed > + * by another one. In that case the unit that has detected it cannot really > + * "close" the "no suspend" period associated with it, unless it knows in > + * advance what's going to happen to the event during processing. This > + * knowledge, however, may not be available to it, so it can simply specify time > + * to wait before the system can be suspended and pass it as the second > + * argument of pm_wakeup_event(). > + */ Since there's no longer any way to cancel a call to pm_wakeup_event() or close the "no suspend" period early, there is no need to use dynamically-allocated delayed_work structures. You can make do with a single static timer; always keep it set to expire at the latest time passed to pm_wakeup_event(). Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
