Re: How to test NAND bad blocks management?

[Richard Weinberger <richard.weinberger@xxxxxxxxx>]

On Mon, Jun 24, 2019 at 10:00 PM JH <jupiter.hce@xxxxxxxxx> wrote:
>
> Hi,
>
> I learned from the list that the kernel is capable of handling NAND
> bad blocks to use the mtd-utils "nandwrite" which I believe has
> already included in kernel, is there any test problem to test the NAND
> bad blocks management? What will be the symptoms when hitting the bad
> blocks, segmentation, kernel error ...?

If you try to operate on a known bad block, MTD will return -EIO.
Linux maintains a bad block table, it contains factory marked bad block
and block which got marked as bad during runtime.
If UBI finds a block which does not behave good, e.g. shows bitflips after
erasure, it will mark it as bad.

What exactly do you want to test?
You can set a bad block marker by hand, or enable UBI's bitflip emulation
via debugfs.

-- 
Thanks,
//richard

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