Enabling CONFIG_MMC_UNSAFE_RESUME

Hans de Goede hdegoede at redhat.com
Thu Feb 6 15:02:38 UTC 2014


Hi,

The mmc subsys has a Kconfig option which more or less mirrors
CONFIG_USB_DEFAULT_PERSIST, which Fedora enables.

I would like to suggest to enable the MMC variant too, without
this on suspend / resume, the kernel will assume that the card
was swapped by one which happens to be of exactly the same type,
thus forcing an unmount off any fs which was on it and killing
any apps which happen to have files open on the device.

For ARM where the rootfs often is on an sdcard this is disastrous,
but one PC-s it is not really userfriendly to kill any fs on
an sdcard on suspend / resume either.

Therefor I would like to suggest that we start enabling
CONFIG_MMC_UNSAFE_RESUME just like we do for
CONFIG_USB_DEFAULT_PERSIST, note that despite the "scary"
naming they are in essence pretty much the same, assume if the
same device is still present after suspend / resume, that it
really is the same device even though we cannot be 100.1 % sure.

Regards,

Hans



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