On Thu, May 27, 2010 at 10:15 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Thu, 2010-05-27 at 15:19 -0400, Alan Stern wrote: >> On Thu, 27 May 2010, Peter Zijlstra wrote: >> >> > I still don't see how blocking applications will cause missed wakeups in >> > anything but a buggy application at worst, and even those will >> > eventually get the event when they unblock. >> > >> > What seems to be the confusion? >> >> During forced suspend, applications are block because they are frozen. >> >> When an event occurs, the application is notified somehow. But it >> can't respond because it is frozen. Hence the event remains sitting in >> a kernel queue and the system goes ahead and suspends anyway. The >> application doesn't get thawed until the system wakes up at some >> indefinite time in the future. > > If the kernel is awake to put things in queues, we're clearly not > suspended and userspace is running ?! Suspend is not an atomic operation. User space is frozen before freezable kernel threads both of these happen before drivers are suspended. -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
