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From:   Richard Weinberger <richard@nod.at>
To:     Pavel Machek <pavel@ucw.cz>
Cc:     linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
        cyrille.pitchen@wedev4u.fr, marek.vasut@gmail.com,
        boris.brezillon@free-electrons.com, computersforpeace@gmail.com,
        dwmw2@infradead.org, dedekind1@gmail.com, tharvey@gateworks.com,
        stable@vger.kernel.org
Subject: Re: [PATCH] ubi: Reject MLC NAND
Date:   Wed, 07 Mar 2018 09:01:16 +0100
Message-ID: <6772577.AmT7QaWTNU@blindfold>
In-Reply-To: <20180306231805.GA28183@amd>
References: <20180303104554.5958-1-richard@nod.at> <20180306231805.GA28183@amd>
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Pavel,

Am Mittwoch, 7. M?rz 2018, 00:18:05 CET schrieb Pavel Machek:
> On Sat 2018-03-03 11:45:54, Richard Weinberger wrote:
> > While UBI and UBIFS seem to work at first sight with MLC NAND, you will
> > most likely lose all your data upon a power-cut or due to read/write
> > disturb.
> > In order to protect users from bad surprises, refuse to attach to MLC
> > NAND.
> > 
> > Cc: stable@vger.kernel.org
> 
> That sounds like _really_ bad idea for stable. All it does is it
> removes support for hardware that somehow works.

MLC is not supported and does not work. Full stop.
If someone manages to get it somehow work, either with hardware or software 
hacks they are on their own.
Having it in stable is the only chance we have to get it into vendor kernels.

All this patch does is representing the current state of UBI/UBIFS.

In the last months I got a way too much boards with MLC NAND on my desk where 
UBIFS broke. Customers wished they had known before...

Thanks,
//richard