Re: [PATCH] mmc: add module parameter to set whether cards are assumed removable

Ben Hutchings
2009-11-22T12:32:17Z

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On Sun, 2009-11-22 at 12:42 +0100, Wouter van Heyst wrote:
> On Mon, Nov 16, 2009 at 10:31:49PM +0000, Ben Hutchings wrote:
[...]
> > In general, it is not possible to tell whether a card present in an MMC
> > slot after resume is the same that was there before suspend. So there
> > are two possible behaviours, each of which will cause data loss in some
> > cases:
> >
> > CONFIG_MMC_UNSAFE_RESUME=n (default): Cards are assumed to be removed
> > during suspend. Any filesystem on them must be unmounted before
> > suspend; otherwise, buffered writes will be lost.
> >
> > CONFIG_MMC_UNSAFE_RESUME=y: Cards are assumed to remain present during
> > suspend. They must not be swapped during suspend; otherwise, buffered
> > writes will be flushed to the wrong card.
> >
> > Currently the choice is made at compile time and this allows that to be
> > overridden at module load time.
>
> I'm running 2.6.32-rc7 with this patch applied and CONFIG_MMC_UNSAFE_RESUME=y
> That works as desired for my non-removable case. Is it desired that I
> test if 'removable=1' will thrash my filesystem?

Please test with CONFIG_MMC_UNSAFE_RESUME=n (which Debian will continue
to use) and removable=0.

Ben.

--
Ben Hutchings
Unix is many things to many people,
but it's never been everything to anybody.

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