From: Boris Brezillon <boris.brezillon@collabora.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-mtd@lists.infradead.org, kernel@pengutronix.de
Subject: Re: Prevent Nand page writes on Power failure
Date: Thu, 21 Feb 2019 11:36:46 +0100 [thread overview]
Message-ID: <20190221113646.6d4eccf1@collabora.com> (raw)
In-Reply-To: <20190221101747.zbznw2mdf7p7rcy4@pengutronix.de>
On Thu, 21 Feb 2019 11:17:47 +0100
Sascha Hauer <s.hauer@pengutronix.de> wrote:
> Hi Boris,
>
> On Thu, Feb 21, 2019 at 09:10:55AM +0100, Boris Brezillon wrote:
> > Hi Sascha,
> >
> > On Wed, 20 Feb 2019 14:58:20 +0100
> > Sascha Hauer <s.hauer@pengutronix.de> wrote:
> >
> > > Hi All,
> > >
> > > I have hardware here for which the normal way to turn off is just to cut
> > > the power. When the powercut happens during a NAND page write then we
> > > get more or less completely written pages during next boot. Very rarely
> > > it seems to happen that such a half written page with only very few
> > > flipped bits is erroneously detected as empty and written again which
> > > then results in ECC errors when reading the data.
> >
> > This should definitely be fixed, maybe by lowering the bitflip
> > threshold when doing the empty check. Do you know the ECC strength and
> > the number of bitflips you have when that problem occurs?
>
> The problem is that these half written pages do not seem to be very
> stable. It happens that the number of bitflips change with each read.
> I have seen pages which can be read sometimes and sometimes not. It
> really seems that half written pages must be avoided entirely.
But when they are correctly read, do you know how many bitflips they
have? To be honest, I fear not all users will be able to be informed
that powercuts are about to happen, and we need a way to fix that for
everyone.
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-02-21 10:37 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 13:58 Prevent Nand page writes on Power failure Sascha Hauer
2019-02-21 0:05 ` Richard Weinberger
2019-02-21 8:39 ` Sascha Hauer
2019-02-21 9:28 ` Richard Weinberger
2019-02-21 8:10 ` Boris Brezillon
2019-02-21 10:17 ` Sascha Hauer
2019-02-21 10:36 ` Boris Brezillon [this message]
2019-02-21 11:21 ` Sascha Hauer
2019-02-21 11:37 ` Boris Brezillon
2019-02-21 12:17 ` Richard Weinberger
2019-02-21 13:27 ` Sascha Hauer
2019-02-25 8:56 ` Sascha Hauer
2019-02-25 11:28 ` Richard Weinberger
2019-02-26 9:10 ` Sascha Hauer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190221113646.6d4eccf1@collabora.com \
--to=boris.brezillon@collabora.com \
--cc=kernel@pengutronix.de \
--cc=linux-mtd@lists.infradead.org \
--cc=s.hauer@pengutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.