On Wednesday, June 30, 2010, Alan Stern wrote: > 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(). The decremenations of events_in_progress wouldn't be balanced with incrementations this way. Or do you have any clever way of dealing with that in mind? Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
