Date: Sat, 3 Jan 2009 23:10:13 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@suse.cz>, Andreas Mohr <andi@lisas.de>,
       Sriram V <vshrirama@gmail.com>, Pierre Ossman <drzeus-list@drzeus.cx>,
       linux-kernel@vger.kernel.org
Subject: Re: Power Management with rootfs on SDMMC.
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> 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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