Re: Power Management with rootfs on SDMMC.

From: Alan Cox
Date: Sat Jan 03 2009 - 18:10:25 EST


> Well, it goes both ways. You can make a nasty mess right now by suspending
> and simply not having a working computer when it comes back - all your
> work being lost.

Yes but these are both symptoms of the same problem.

> they actually get things right is pretty low, though. So I suspect we'd be
> much better off having sane defaults in the kernel instead.

I don't believe "auto-destroy my music collection" is a sane default...

> So it boils down to the fact that if you have something like / or /home
> mounted, we really _cannot_ do any better than "assume the user doesn't
> screw us up".
>
> A per-filesystem callback to re-verify at resume might be a good idea, but
> a lot of filesystems cannot reasonably do a lot of verification.

A per file system sync and quiesce is I think also part of the
requirement. Having the file system media consistent but still mounted
before suspending is a good thing anyway (especially with stuff like USB
keys that people do then go and remove post suspend) and you can put the
device into a consistent state and revalidate it *regardless* of the
whether it is / or a music player. What you do if revalidating / fails is
another question ;)

Alan
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