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    SubjectRe: [RFC][PATCH -mm 1/3] PM: Hibernation and suspend notifiers
    Hi!

    > +Suspend notifiers
    > + (C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL
    > +
    > +There are some operations that device drivers may want to carry out in their
    > +.suspend() routines, but shouldn't, because they can cause the hibernation or
    > +suspend to fail. For example, a driver may want to allocate a substantial amount
    > +of memory (like 50 MB) in .suspend(), but that shouldn't be done after the
    > +swsusp's memory shrinker has run.
    > +
    > +Also, there may be some operations, that subsystems want to carry out before a
    > +hibernation/suspend or after a restore/resume, requiring the system to be fully
    > +functional, so the drivers' .suspend() and .resume() routines are not suitable
    > +for this purpose. For example, device drivers may want to upload firmware to
    > +their devices after a restore from a hibernation image, but they cannot do it by
    > +calling request_firmware() from their .resume() routines (user land processes
    > +are frozen at this point). The solution may be to load the firmware into
    > +memory before processes are frozen and upload it from there in the .resume()
    > +routine. Of course, a hibernation notifier may be used for this purpose.
    > +
    > +The subsystems that have such needs can register suspend notifiers that will be
    > +called upon the following events by the suspend core:
    > +
    > +PM_PRE_FREEZE The system is going to hibernate or suspend, tasks will
    > + be frozen immediately

    Hmm, looks like bad idea if we are going to remove freezer from
    suspend...?

    > +PM_POST_THAW Tasks have just been thawed after a resume or restore
    > + from a hibernation image
    > +
    > +PM_HIBERNATION_PREPARE The system is preparing for hibernation. Tasks have
    > + been frozen, memory is going to be freed and devices
    > + are going to be suspended.

    Is not PRE_FREEZE enough? We can allocate memory for drivers there,
    too...

    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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