On Sun, 8 Aug 2010, Rafael J. Wysocki wrote: > > > Also please note that it depends a good deal on the definition of a "wakeup > > > event". Under the definition used when my patch was being developed, ie. that > > > wakeup events are the events that would wake up the system from a sleep state, > > > PCI interrupts cannot be wakeup events, unless the given device remains in the > > > full power state although the system has been suspended (standard PCI devices > > > are not allowed to generate signals except for PME from low-power states). > > > > Um, what do you mean by "event"? Let's take a concrete example. > > Suppose you have a system where you want USB plug or unplug events to > > cause a wakeup. This is relevant to the discussion at hand if your USB > > host controller is a PCI device. > > > > By your reckoning, a plug or unplug event that occurs while the system > > is asleep would be a wakeup event by definition. And yet you say that > > the same plug or unplug event occurring while the controller was at > > full power would not count as a wakeup event? And in particular, it > > should not prevent the system from suspending before the event can be > > fully processed? That doesn't make sense. The same event is the same > > event, regardless of the context in which it occurs. If it is treated > > as a wakeup event in context then it should be treated as a wakeup > > event in other contexts too. > > In this example the event is not a PCI interrupt itself, which is a consqeuence > of the event, but the USB plug-unplug. So, whoever detects the plug-unplug > should use pm_stay_awake() or pm_wakeup_event(). That may be an > interrupt handler of a PCI USB controller, so if that is the case, the > controller driver probably should use one of these functions in its interrupt > handler. Still, that by no measn implies that _every_ PCI interrupt should in > principle be regarded as a wakeup event. Okay, agreed. I just wanted you to grant that some PCI interrupts should be treated like wakeup events even if they don't actually wake the system up from a sleep state. The "PCI interrupts cannot be wakeup events" statement is a little strong. Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
