From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from co202.xi-lite.net ([149.6.83.202]) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1RGTIM-0001wm-Uc for linux-mtd@lists.infradead.org; Wed, 19 Oct 2011 10:22:47 +0000 Date: Wed, 19 Oct 2011 12:22:35 +0200 From: Ivan Djelic To: Ricard Wanderlof Subject: Re: UBIFS recovery fails Message-ID: <20111019102235.GA13501@parrot.com> References: <4E9C2DAC.7090109@swissonline.ch> <1318882668.2172.10.camel@koala> <225442585F89274EA3A62F88671ECBAC0D33C8E2@prod-svr-1.intranet.str.ca> <20111018145413.GA8576@parrot.com> <225442585F89274EA3A62F88671ECBAC0D33C8EB@prod-svr-1.intranet.str.ca> <20111018153236.GA10466@parrot.com> <225442585F89274EA3A62F88671ECBAC0D33C8F2@prod-svr-1.intranet.str.ca> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: Cc: "linux-mtd@lists.infradead.org" , =?utf-8?Q?Jean-S=C3=A9bastien?= Gagnon List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Oct 19, 2011 at 07:50:42AM +0100, Ricard Wanderlof wrote: > That said, it seems to me that power failure during write causing > excessive bitflips would be a problem with any flash, not just MLC or > modern "unstable" SLC. Ivan, you said you've only seen it with modern > flashes, not older SLC ? Excessive bitflips after a power failure happen on all types of flash (SLC, MLC, even NOR flash); it is an expected possible consequence of the power cut. It is not really a problem as long as what you read in flash is _stable_. On modern SLCs (at least I first saw it on 34 nm SLC flash), those bitflips can be _unstable_, i.e. they can appear and disappear randomly as you read pages. I experienced this phenomenon only on pages which were being programmed or erased during a power cut. BR, -- Ivan