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linux/drivers/mmc/core/Kconfig

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mmc: support unsafe resume of cards Since many have the system root on MMC/SD we must allow some foot shooting when it comes to resume. We cannot detect if a card is removed and reinserted during suspend, so the safe approach would be to assume it was, avoiding potential filesystem corruption. This will of course not work if you cannot release the card before suspend. This commit adds a compile time option that makes the MMC layer assume the card wasn't touched if it is redetected upon resume. Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 22:00:02 +08:00
#
# MMC core configuration
#
config MMC_UNSAFE_RESUME
mmc: add module parameter to set whether cards are assumed removable Some people run general-purpose distribution kernels on netbooks with a card that is physically non-removable or logically non-removable (e.g. used for /home) and cannot be cleanly unmounted during suspend. Add a module parameter to set whether cards are assumed removable or non-removable, with the default set by CONFIG_MMC_UNSAFE_RESUME. 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. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Wouter van Heyst <larstiq@larstiq.dyndns.org> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 10:01:29 +08:00
bool "Assume MMC/SD cards are non-removable (DANGEROUS)"
mmc: support unsafe resume of cards Since many have the system root on MMC/SD we must allow some foot shooting when it comes to resume. We cannot detect if a card is removed and reinserted during suspend, so the safe approach would be to assume it was, avoiding potential filesystem corruption. This will of course not work if you cannot release the card before suspend. This commit adds a compile time option that makes the MMC layer assume the card wasn't touched if it is redetected upon resume. Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 22:00:02 +08:00
help
If you say Y here, the MMC layer will assume that all cards
stayed in their respective slots during the suspend. The
normal behaviour is to remove them at suspend and
redetecting them at resume. Breaking this assumption will
in most cases result in data corruption.
This option is usually just for embedded systems which use
a MMC/SD card for rootfs. Most people should say N here.
mmc: add module parameter to set whether cards are assumed removable Some people run general-purpose distribution kernels on netbooks with a card that is physically non-removable or logically non-removable (e.g. used for /home) and cannot be cleanly unmounted during suspend. Add a module parameter to set whether cards are assumed removable or non-removable, with the default set by CONFIG_MMC_UNSAFE_RESUME. 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. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Wouter van Heyst <larstiq@larstiq.dyndns.org> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 10:01:29 +08:00
This option sets a default which can be overridden by the
module parameter "removable=0" or "removable=1".
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