Bug#743933: Please enable CONFIG_MTD_NAND_ECC_BCH
Package: linux
Version: 3.2.54-2
Severity: normal
Tags: patch
Hi,
The industry trend for NAND devices (for the last few years now and with
no sign of abating) appears to be to trade reliability for die size and
speed, and to leave it to error correction algorithms to try and backfill
the data integrity gap.
Parts that previously recommended 1-bit ECC are becoming unavailable and
their 'equivalent' replacements require 4-bit ECC or better. Not all
NAND controllers are able to do this yet, so software ECC is required in
those cases.
I have a device that can mount its NAND as an MTD device directly on the
host PC, and have been doing this with NAND_ECC_SOFT for quite some time,
but NAND_ECC_SOFT_BCH fails unless the host kernel has been built with
support for that, which our current kernels are not.
I've tested enabling this with the linux-source-3.2 package with the
following change to the config, and it all then works as expected.
Cheers,
Ron
--- /boot/config-3.2.0-4-amd64 2014-02-02 11:46:29.000000000 +1030
+++ .config 2014-04-08 22:45:10.000000000 +0930
@@ -1,6 +1,6 @@
#
# Automatically generated file; DO NOT EDIT.
-# Linux/x86 3.2.54 Kernel Configuration
+# Linux/x86_64 3.2.54 Kernel Configuration
#
CONFIG_64BIT=y
# CONFIG_X86_32 is not set
@@ -1430,7 +1430,8 @@
# CONFIG_MTD_NAND_ECC_SMC is not set
CONFIG_MTD_NAND=m
# CONFIG_MTD_NAND_VERIFY_WRITE is not set
-# CONFIG_MTD_NAND_ECC_BCH is not set
+CONFIG_MTD_NAND_BCH=m
+CONFIG_MTD_NAND_ECC_BCH=y
CONFIG_MTD_SM_COMMON=m
# CONFIG_MTD_NAND_MUSEUM_IDS is not set
# CONFIG_MTD_NAND_DENALI is not set
@@ -5637,6 +5638,7 @@
CONFIG_GENERIC_ALLOCATOR=y
CONFIG_REED_SOLOMON=m
CONFIG_REED_SOLOMON_DEC16=y
+CONFIG_BCH=m
CONFIG_TEXTSEARCH=y
CONFIG_TEXTSEARCH_KMP=m
CONFIG_TEXTSEARCH_BM=m
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