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>
diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
new file mode 100644
index 0000000..94222b9
--- /dev/null
+++ b/drivers/mmc/core/Kconfig
@@ -0,0 +1,17 @@
+#
+# MMC core configuration
+#
+
+config MMC_UNSAFE_RESUME
+ bool "Allow unsafe resume (DANGEROUS)"
+ depends on MMC != n
+ 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.
+