[YAFFS] bad block management policy

[Artem Bityutskiy]

On Thu, 2012-08-09 at 10:24 -0400, Peter Barada wrote:
> You could modify YAFFS to ignore -EUCLEAN returns from MTD which will
> prevent YAFFS from marking blocks bad prematurely, but then there is no
> way to predict when a block is about to wear out and return
> uncorrectable errors (-EBADMSG).

We recently improved this area and now you also can set the bitflip
threshold in the MTD so that MTD won't return -EUCLEAN unless the amount
of bits flipped is larger than the threshold. The idea is that UBI
scrubs eraseblocks (moves data to different ones) in case of bitflips.
But 1-bit flips happen so often on some devices, that it is wiser to
ignore those. So now the driver can set the level on which MTD will
start returning -EUCLEAN. Below that flip level, it will return 0.

So this also means that if you set the threshold = ECC strength, you
should never even get -EUCLEAN. Not sure it is good idea, but a
possibility as well.

-- 
Best Regards,
Artem Bityutskiy
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: This is a digitally signed message part
URL: <http://lists.infradead.org/pipermail/linux-mtd/attachments/20120824/97cf18cc/attachment.sig>