Re: Power Management with rootfs on SDMMC.
[Posted January 7, 2009 by corbet]
From: |
| Alan Cox <alan-AT-lxorguk.ukuu.org.uk> |
To: |
| Linus Torvalds <torvalds-AT-linux-foundation.org> |
Subject: |
| Re: Power Management with rootfs on SDMMC. |
Date: |
| Sat, 3 Jan 2009 23:10:13 +0000 |
Message-ID: |
| <20090103231013.3591d027@lxorguk.ukuu.org.uk> |
Cc: |
| Pavel Machek <pavel-AT-suse.cz>, Andreas Mohr <andi-AT-lisas.de>,
Sriram V <vshrirama-AT-gmail.com>,
Pierre Ossman <drzeus-list-AT-drzeus.cx>,
linux-kernel-AT-vger.kernel.org |
Archive‑link: | |
Article |
> 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