From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754583AbbHFE2w (ORCPT ); Thu, 6 Aug 2015 00:28:52 -0400 Received: from mx.dave-tech.it ([2.229.21.40]:36820 "EHLO mx.dave-tech.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754411AbbHFE2v (ORCPT ); Thu, 6 Aug 2015 00:28:51 -0400 Subject: Re: [RFC PATCH 2/2] mtd: nand: use nand_check_erased_ecc_chunk in default ECC read functions To: Richard Weinberger , Boris Brezillon References: <1438277694-23763-3-git-send-email-boris.brezillon@free-electrons.com> <55BB48D9.6050508@dave-tech.it> <20150731123221.34cf601e@bbrezillon> <55BB7ABD.7040008@dave-tech.it> <20150731161032.2b155ccb@bbrezillon> <55BBA012.4080600@dave-tech.it> <20150731182709.14c345df@bbrezillon> <55BF4D72.8090000@dave-tech.it> <20150803144253.66fc6941@bbrezillon> <55BF6F09.9000001@dave-tech.it> <55BFC1DA.3090108@nod.at> <55C06379.5090705@dave-tech.it> <55C067F7.3000309@nod.at> Cc: linux-mtd@lists.infradead.org, David Woodhouse , Brian Norris , linux-kernel@vger.kernel.org, Han Xu , Artem Bityutskiy From: Andrea Scian Message-ID: <55C2E27D.3030406@dave-tech.it> Date: Thu, 6 Aug 2015 06:28:45 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <55C067F7.3000309@nod.at> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Antivirus: avast! (VPS 150805-2, 05/08/2015), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 04/08/2015 09:21, Richard Weinberger ha scritto: > Andrea, > > Am 04.08.2015 um 09:02 schrieb Andrea Scian: >>> I'm not sure whether introducing a read-before-write check is the best solution. >>> At least we need hard numbers for slow/old SLC NANDs too. >> >> We can enable the feature only for MLC, AFAIK it has not been required for old SLC ;-) > > I think this needs more discussion. > > Boris, Brian, will you be at Embedded Linux Conference Europe in Dublin? > Maybe we can discuss these issues (data retention, ff-checks, etc...) in person and > figure out where to address them. > I really want to avoid ad-hoc solutions. :) Maybe I'll be at ELCE this year too I'll be glad to meet all of you in person and participate to this discussion. :) It will be nice if also some silicon vendor would like to participate. I know that someone from micron is actively following us on this ML, but I don't really know if there's someone here in Europe. :) > >> Thanks. >> In your opinion, enabling chk_io is correct to rough estimate the overhead >> or does it enable too much checks? > > You mean the other checks bedside of self_check_write()? You can comment them out > for your tests. > > Thanks, > //richard > Kind Regards, -- Andrea SCIAN DAVE Embedded Systems