kernel defconfig, CONFIG_MTD_NAND_VERIFY_WRITE

Werner Almesberger werner at openmoko.org
Wed Jan 6 22:57:16 CET 2010


Gennady Kupava wrote:
> even more interesting, why it is disabled? according to datasheet
> SC32442B have one. next thing for investigation.

I don't remember the exact reason why we disabled it in the first
place, but I think it was some bug in the ECC calculation. There
was also an API change in the kernel that caused incorrect
"corrections" to be applied.

Eventually, that problem was solved, but then we had the issue of
u-boot and kernel disagreeing on the ECC (sw and hw differ). Only
if updating both programs, you would get the correct result.

This coordinated transition was further complicated by having an
immutable u-boot in NOR. Murphy is watchful :)

So, in the end we never made the switch, even though the technical
reason for using software ECC had disappeared by then. (Except
for u-boot in NOR, of course.)

- Werner



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