On Sun, 2009-12-06 at 22:15 -0800, Linus Torvalds wrote: > > The same is true of the prepare_suspend/suspend split I'm proposing: > I > suspect that for something like USB, it would make most sense to just > do > normal node suspend in prepare_suspend, which would do everything > asynchronously. Only USB hub devices would get involved at the later > 'suspend()' phase. Wasn't part of the goal with prepare_suspend() vs. suspend() to handle the problem of backing store vs the VM ? IE. Once any device potentially in the VM path is suspended, things like kmalloc() or gfp() can potentially stall until resume or did we address that recently ? Iirc, part of the idea behind prepare_* is that it's safe vs. the above. Now if you start suspending USB devices at prepare() then you break that assumption since those could be mass storage with dirty mmap'ed pages on them. Now, I'm all for fixing it at the VM/allocator level (if we didn't already) turning pretty much everything into NO_IO once we start suspending devices but that's a whole different matter :-) Cheers, Ben. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
