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From: "Steffen Kühn" <sk@ammonit.com>
To: David Mosberger-Tang <dmosberger@gmail.com>
Cc: "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>
Subject: Re: Changing the ECC method for a running system (UBI seems to use OOB?)
Date: Fri, 12 Apr 2013 11:12:42 +0200	[thread overview]
Message-ID: <5167D00A.1090006@ammonit.com> (raw)
In-Reply-To: <CACwUX0PEfQfNa_Yg5JFEWFsFAC++Y1MgmPmckE5_2KZG8YuEOw@mail.gmail.com>

Hello David,

> We had exactly the same issue with our embedded systems (I'm really mad at
> Micron that they released the 4-bit ECC chips without as much as putting a
> warning message in the Linux kernel, but that's a separate topic...).
> 
> Anyhow, we modified the AT91bootstrap loader to convert the entire NAND
> from 1-bit sw-ecc to on-die 4-bit ECC.  I'd be happy to send a patch to
> this mailing list if you think this would be useful.

Yes, this would be great! The patch is certainly also helpful for the
next with the same problem ...

> 
> UBI fortunately does not use OOB at all, so there should be no issue from
> there.
I have read this too. I'm happy that I have not to deal with YAFFS2.

> 
> The subpage size has to match though.  In our case, UBI was built for 512B
> subpage, but when turning on the on-die ECC support, it'd by default only
> support 2048B pages.  The patch I sent earlier to this mailing list enables
> 512B subpage writes with on-die ECC.

That could be my problem. I have not considered this point. Thanks!

Best regards,
Steffen

  reply	other threads:[~2013-04-12  9:09 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-11 16:29 Changing the ECC method for a running system (UBI seems to use OOB?) Steffen Kühn
2013-04-11 16:34 ` David Mosberger-Tang
2013-04-12  9:12   ` Steffen Kühn [this message]
2013-04-12 10:37     ` Angus CLARK

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