Commit 021796b8 authored by Mike Dunn's avatar Mike Dunn Committed by David Woodhouse

mtd: ABI documentation: clarification of bitflip_threshold

The -EUCLEAN return value applies to mtd_read_oob() as well as mtd_read(), but
only mtd_read() was mentioned in the blurd on bitflip_threshold in the ABI
documentation.
Signed-off-by: default avatarMike Dunn <mikedunn@newsguy.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 6023813a
......@@ -142,13 +142,14 @@ KernelVersion: 3.4
Contact: linux-mtd@lists.infradead.org
Description:
This allows the user to examine and adjust the criteria by which
mtd returns -EUCLEAN from mtd_read(). If the maximum number of
bit errors that were corrected on any single region comprising
an ecc step (as reported by the driver) equals or exceeds this
value, -EUCLEAN is returned. Otherwise, absent an error, 0 is
returned. Higher layers (e.g., UBI) use this return code as an
indication that an erase block may be degrading and should be
scrutinized as a candidate for being marked as bad.
mtd returns -EUCLEAN from mtd_read() and mtd_read_oob(). If the
maximum number of bit errors that were corrected on any single
region comprising an ecc step (as reported by the driver) equals
or exceeds this value, -EUCLEAN is returned. Otherwise, absent
an error, 0 is returned. Higher layers (e.g., UBI) use this
return code as an indication that an erase block may be
degrading and should be scrutinized as a candidate for being
marked as bad.
The initial value may be specified by the flash device driver.
If not, then the default value is ecc_strength.
......@@ -167,7 +168,7 @@ Description:
block degradation, but high enough to avoid the consequences of
a persistent return value of -EUCLEAN on devices where sticky
bitflips occur. Note that if bitflip_threshold exceeds
ecc_strength, -EUCLEAN is never returned by mtd_read().
ecc_strength, -EUCLEAN is never returned by the read operations.
Conversely, if bitflip_threshold is zero, -EUCLEAN is always
returned, absent a hard error.
......
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