All of lore.kernel.org
 help / color / mirror / Atom feed
From: Richard Weinberger <richard@nod.at>
To: "Csókás Bence" <csokas.bence@prolan.hu>
Cc: "Michael Walle" <mwalle@kernel.org>,
	linux-mtd <linux-mtd@lists.infradead.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"Szentendrei, Tamás" <szentendrei.tamas@prolan.hu>,
	"Tudor Ambarus" <tudor.ambarus@linaro.org>,
	pratyush <pratyush@kernel.org>,
	"Miquel Raynal" <miquel.raynal@bootlin.com>,
	"Vignesh Raghavendra" <vigneshr@ti.com>
Subject: Re: [PATCH] spi-nor: Verify written data in paranoid mode
Date: Wed, 16 Apr 2025 15:09:03 +0200 (CEST)	[thread overview]
Message-ID: <373620122.295980015.1744808943985.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <dd3c7cc0-a568-4046-b105-e6786b5c80f8@prolan.hu>

----- Ursprüngliche Mail -----
> Von: "Csókás Bence" <csokas.bence@prolan.hu>
>>> Add MTD_SPI_NOR_PARANOID config option for verifying all written data to
>>> prevent silent bit errors to be undetected, at the cost of halving SPI
>>> bandwidth.
>> 
>> What is the use case for this? Why is it specific to SPI-NOR
>> flashes? Or should it rather be an MTD "feature". I'm not sure
>> whether this is the right way to do it, thus I'd love to hear more
>> about the background story to this.
> 
> Well, our case is quite specific, but we wanted to provide a general
> solution for upstream. In our case we have a component in the data path
> that can cause a burst bit error, on average after about a hundred
> megabytes written.

Hmm. So, there is a serve hardware issue you're working around.

> We _could_ make it MTD-wide, in our case we only have a NOR Flash
> onboard so this is where we added it. If it were in the MTD core, where
> would it make sense?

I'm not so sure whether it makes sense at all.
In it's current form, there is no recovery. So anything non-trivial
on top of the MTD will just see an -EIO and has to give up.
E.g. a filesystem will remount read-only.

Thanks,
//richard

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard@nod.at>
To: "Csókás Bence" <csokas.bence@prolan.hu>
Cc: "Michael Walle" <mwalle@kernel.org>,
	linux-mtd <linux-mtd@lists.infradead.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"Szentendrei, Tamás" <szentendrei.tamas@prolan.hu>,
	"Tudor Ambarus" <tudor.ambarus@linaro.org>,
	pratyush <pratyush@kernel.org>,
	"Miquel Raynal" <miquel.raynal@bootlin.com>,
	"Vignesh Raghavendra" <vigneshr@ti.com>
Subject: Re: [PATCH] spi-nor: Verify written data in paranoid mode
Date: Wed, 16 Apr 2025 15:09:03 +0200 (CEST)	[thread overview]
Message-ID: <373620122.295980015.1744808943985.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <dd3c7cc0-a568-4046-b105-e6786b5c80f8@prolan.hu>

----- Ursprüngliche Mail -----
> Von: "Csókás Bence" <csokas.bence@prolan.hu>
>>> Add MTD_SPI_NOR_PARANOID config option for verifying all written data to
>>> prevent silent bit errors to be undetected, at the cost of halving SPI
>>> bandwidth.
>> 
>> What is the use case for this? Why is it specific to SPI-NOR
>> flashes? Or should it rather be an MTD "feature". I'm not sure
>> whether this is the right way to do it, thus I'd love to hear more
>> about the background story to this.
> 
> Well, our case is quite specific, but we wanted to provide a general
> solution for upstream. In our case we have a component in the data path
> that can cause a burst bit error, on average after about a hundred
> megabytes written.

Hmm. So, there is a serve hardware issue you're working around.

> We _could_ make it MTD-wide, in our case we only have a NOR Flash
> onboard so this is where we added it. If it were in the MTD core, where
> would it make sense?

I'm not so sure whether it makes sense at all.
In it's current form, there is no recovery. So anything non-trivial
on top of the MTD will just see an -EIO and has to give up.
E.g. a filesystem will remount read-only.

Thanks,
//richard

  reply	other threads:[~2025-04-16 13:09 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-15 18:04 [PATCH] spi-nor: Verify written data in paranoid mode Bence Csókás
2025-04-15 18:04 ` Bence Csókás
2025-04-16 11:59 ` Michael Walle
2025-04-16 11:59   ` Michael Walle
2025-04-16 12:38   ` Csókás Bence
2025-04-16 12:38     ` Csókás Bence
2025-04-16 13:09     ` Richard Weinberger [this message]
2025-04-16 13:09       ` Richard Weinberger
2025-04-16 14:44       ` Csókás Bence
2025-04-16 14:44         ` Csókás Bence
2025-04-16 18:41         ` Richard Weinberger
2025-04-16 18:41           ` Richard Weinberger
2025-05-08  9:42           ` Csókás Bence
2025-05-08  9:42             ` Csókás Bence

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=373620122.295980015.1744808943985.JavaMail.zimbra@nod.at \
    --to=richard@nod.at \
    --cc=csokas.bence@prolan.hu \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=miquel.raynal@bootlin.com \
    --cc=mwalle@kernel.org \
    --cc=pratyush@kernel.org \
    --cc=szentendrei.tamas@prolan.hu \
    --cc=tudor.ambarus@linaro.org \
    --cc=vigneshr@ti.com \
    /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.