On Wed, 21 Jun 2006, Linus Torvalds wrote: > > > - userland will stop responding at any point in time in the future (as > > soon as the backing store of a given process or swap is put to sleep, or > > maybe blocked in an ioctl of a sleeping driver or whatver > > Exact same thing. This has _nothing_ to do with save_state(), and is no > different from what we have now, in exactly the same ways. > > And btw, in my suggested setup, you actually _do_ get that notification, > ie the "freeze()" thing tells you that if you're doing snapshotting etc, > that's the point where processes have also been put to sleep. On a somewhat tangential notion: if a driver actually cares about which phase is going on, we do have the "system_state" variable. Traditionally, we've not done a lot to it, but some kernel infrastructure has wanted to know whether the system is "booting" or "running", and there's certainly nothing wrong with adding a state for "shutting down". I don't actually see very many drivers caring, but we could certainly add a state and make sure it's set when the suspend cycle starts (or even set it to different values for different parts of the cycle). For some strange reason, almost half the users of that variable are in the powerpc tree. That may be enough for whatever you had in mind (adding notification of each phase seems to be a bit overkill). Linus
