Hi! > +Suspend notifiers > + (C) 2007 Rafael J. Wysocki <rjw@xxxxxxx>, 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 _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
