From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from co202.xi-lite.net ([149.6.83.202]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TWXRf-0001Ey-95 for linux-mtd@lists.infradead.org; Thu, 08 Nov 2012 19:07:19 +0000 Date: Thu, 8 Nov 2012 20:07:14 +0100 From: Ivan Djelic To: Gerlando Falauto Subject: Re: state of support for "external ECC hardware" Message-ID: <20121108190714.GD28118@parrot.com> References: <20121029204227.GA32300@harvey-pc.matrox.com> <509B9143.4020506@keymile.com> <20121108152125.GR2389@harvey-pc.matrox.com> <509BDE9B.3080909@keymile.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <509BDE9B.3080909@keymile.com> Cc: "Bigler, Stefan" , Christopher Harvey , "Brunck, Holger" , "linux-mtd@lists.infradead.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Nov 08, 2012 at 04:32:27PM +0000, Gerlando Falauto wrote: (...) > Right, datasheets and TNs don't even mention what the threshold actually > is. They just say "Rewrite recommended". Perhaps you could get some > feeling while running your tests? I mean, if you could get bitflips by > using host-software ECC (within a reasonable time), and after enabling > on-die ECC you couldn't anymore, it probably means HW ECC won't tell you > about bitflips until they reach a number higher than 1. Am I right? > > [Did you ever ask Micron by any chance?] IIRC, Micron on-die ECC reports a "rewrite recommended" status when the number of bitflips has reached the internal error correction capability (4 in my case). In other words, a "rewrite recommended" means you should rewrite the block ASAP before an additional bitflip triggers an ECC failure. -- Ivan