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Subject: Re: What would cause large block of NAND to be marked as bad?
From: Artem Bityutskiy <dedekind1@gmail.com>
To: Subodh Nijsure <snijsure@grid-net.com>
Date: Mon, 07 May 2012 21:56:49 +0300
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On Mon, 2012-05-07 at 11:05 -0700, Subodh Nijsure wrote:
> Hello,
>=20
> I am working with some prototype hardware and I have seen some weird=20
> behaviour when testing power cut.
>=20
> On my board I have Micron MT29F2G08ABAEAH4 part and now have three=20
> boards on which close to 20-30 blocks have been marked as bad.
>=20
> We mainly run UBIFS on these boards, if there was flash data corruption=
=20
> we expected to see errors at UBIFS level i.e. not able to mount UBIFS=20
> file system but we didn't expect NAND blocks themselves to be marked as=
=20
> bad, due to power cut.
>=20
> What would cause large number of NAND blocks to be marked as bad, due to=
=20
> power cut?

Did you look at Mike Dunn's bitflip_threshold stuff? It is in my
l2-mtd.git tree. Look at this patch and the next ones from Mike:

http://git.infradead.org/users/dedekind/l2-mtd.git/commit/be1bb4ef1f98059f9=
d54623f3ed01423095fa967

Commit messages contain descriptions and references. May be for your
flash you need to set higher threshold?

--=20
Best Regards,
Artem Bityutskiy

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