Hi! > > > But remember there are even in-kernel s2ram triggers, for example on > > > zaurus when battery goes critical. > > > > > Take ACPI for example, ACPI defines two ACPI battery states, one is > "low" and another is "critical". > OS enters S3/S4 when battery is low, while it performs an emergency > shutdown when battery is in critical state. (ACPI spec 3.0b 3.9.4) > So I'm wondering if it's right to enter S3 when we know that the system > may lost power at anytime. Well, battery only lasts like 30 hours in S3. So if you leave your notebook unattended for 30 hours, you'll loose recent changes. > > > (And s2ram without sync _is_ "wrong": writeback timeouts are not > > > honored). > any kind of suspend can't meet this requirement. Even sys_sync is > called, there is a small window that some pages are dirtied, but are not > synced to disk in max expire interval, right? Not if you do sys_sync() after freeze of userspace. (I'm not 100% sure there's no race in there somewhere, but I'd prefer not to make the race bigger.) 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
