From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:59640 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754039AbeCGWRf (ORCPT ); Wed, 7 Mar 2018 17:17:35 -0500 Date: Wed, 7 Mar 2018 23:17:33 +0100 From: Pavel Machek To: David Woodhouse , Greg KH Cc: Steve deRosier , Richard Weinberger , Boris Brezillon , dedekind1@gmail.com, tharvey@gateworks.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, marek.vasut@gmail.com, linux-mtd@lists.infradead.org, cyrille.pitchen@wedev4u.fr, computersforpeace@gmail.com Subject: Re: [PATCH] ubi: Reject MLC NAND Message-ID: <20180307221733.GE10438@amd> References: <20180303104554.5958-1-richard@nod.at> <20180306231805.GA28183@amd> <6772577.AmT7QaWTNU@blindfold> <20180307214342.GA9852@amd> <1520460673.31298.136.camel@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1520460673.31298.136.camel@infradead.org> Sender: stable-owner@vger.kernel.org List-ID: On Wed 2018-03-07 22:11:13, David Woodhouse wrote: > > > On Wed, 2018-03-07 at 14:08 -0800, Steve deRosier wrote: > > > > To clarify one thing: the reason for this is MLC has actually never > > been supported, nor worked properly. The fact that it kinda worked was > > incidental and the cause of major problems for people due to that not > > being clear. This patch only makes it explicit and avoids people > > mistakenly trying to use UBIFS on MLC flash and risking their data and > > products. To me, that's what's important. > > > > This is an important patch, even if all it does is keep people from > > loosing data. It also changes the conversation from "I have a > > corrupted UBIFS device, BTW it's on MLC..." to "What can we do to get > > UBIFS to work on MLC". Well, for -stable I'd suggest printk(KERN_ALERT ...) but keep the system running. > This is a bug fix. > > UBI on MLC never worked. It was a bug that we ever permitted it. This > is now fixed. Yeah, well, so lets say I have a working hardware (maybe using read-only UBI on MLC), update to next stable kernel, and now kernel refuses to see the partition. I'll certainly not consider this patch a bug fix. Removing support for hardware that "only works by mistake" may be good idea, but maybe it is slightly too surprising for a -stable. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html