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What would cause large block of NAND to be marked as bad?

DISCUSSION Subodh Nijsure 2 participants 2 messages May 7, 2012 Memory technology devices (MTD)

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Hello,

I am working with some prototype hardware and I have seen some weird behaviour when testing power cut.

On my board I have Micron MT29F2G08ABAEAH4 part and now have three boards on which close to 20-30 blocks have been marked as bad.

We mainly run UBIFS on these boards, if there was flash data corruption we expected to see errors at UBIFS level i.e. not able to mount UBIFS file system but we didn't expect NAND blocks themselves to be marked as bad, due to power cut.

What would cause large number of NAND blocks to be marked as bad, due to power cut?

-Subodh

#1 lore raw
Quoted 8 lines · Subodh Nijsure

Hello,

I am working with some prototype hardware and I have seen some weird behaviour when testing power cut.

On my board I have Micron MT29F2G08ABAEAH4 part and now have three boards on which close to 20-30 blocks have been marked as bad.

Quoted 7 lines

We mainly run UBIFS on these boards, if there was flash data corruption we expected to see errors at UBIFS level i.e. not able to mount UBIFS file system but we didn't expect NAND blocks themselves to be marked as bad, due to power cut.

What would cause large number of NAND blocks to be marked as bad, due to 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/be1bb4ef1f98059f9d54623f3ed01423095fa967

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

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Artem Bityutskiy