On Thu, 3 May 2007, Rafael J. Wysocki wrote: > On Thursday, 3 May 2007 12:34, Paul Mackerras wrote: > > Rafael J. Wysocki writes: > > > > > I think that on a uniprocessor system it's quite safe, but on SMP it doesn't > > > seem so. For example, imagine the situation in which one CPU is executing the > > > suspend code while another one is running userspace with system calls etc. > > > Pretty scary. > > > > Which is why the powermac/powerbook sleep code insists on there only > > being one cpu active. I have an SMP powermac which can sleep; I use a > > little script to take the second cpu down before sleeping and bring it > > back up after waking up. > > That's quite intrusive. Ideally, user space processes should not notice that > there have been a suspend at one point. What happens without preemption enabled when a device driver's suspend() method calls schedule()? With or without preemption enabled, what happens when a user process tries to do I/O to a suspended device? Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
