From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-bw0-f49.google.com ([209.85.214.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1RPgeo-0000Gz-VO for linux-mtd@lists.infradead.org; Sun, 13 Nov 2011 20:28:03 +0000 Received: by bkat2 with SMTP id t2so7482381bka.36 for ; Sun, 13 Nov 2011 12:28:00 -0800 (PST) Subject: Re: [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo From: Artem Bityutskiy To: Mike Dunn Date: Sun, 13 Nov 2011 22:27:50 +0200 In-Reply-To: <4EC020A2.9070003@newsguy.com> References: <1320912342-30147-1-git-send-email-robert.jarzmik@free.fr> <1320912342-30147-8-git-send-email-robert.jarzmik@free.fr> <4EBECB89.2020102@newsguy.com> <87vcqoiavr.fsf@free.fr> <1321188825.2273.4.camel@koala> <1321189398.2021.5.camel@shinybook.infradead.org> <1321191352.2273.14.camel@koala> <87ehxchta0.fsf@free.fr> <4EC020A2.9070003@newsguy.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Message-ID: <1321216077.26585.11.camel@koala> Mime-Version: 1.0 Cc: David Woodhouse , Ivan Djelic , Robert Jarzmik , linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, 2011-11-13 at 11:55 -0800, Mike Dunn wrote: > An objection might be that mtd should not be setting policy. It's also a fairly > sizeable modification. The alternative would be to implement a mechanism to > return the corrected error count to the higher layer (e.g., ubi) for each read > operation. This would be even more work, requiring modifications to mtd and ubi. Yeah, probably just returning the ECC correction count is cleaner design. Probably we can add another argument to the mtd read function and if the return code is -EUCLEAN (correctable bit-flips happened), it would contain the highest ECC correction count encountered while reading this region of the flash. So the SW which does not care, will not require any changes. I am not sure if you'll need to mtd interfaces from mtd->func(...) to mtd_func(mtd, ...) for this or not, though. Artem. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754625Ab1KMU2D (ORCPT ); Sun, 13 Nov 2011 15:28:03 -0500 Received: from mail-bw0-f46.google.com ([209.85.214.46]:44707 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751308Ab1KMU2B (ORCPT ); Sun, 13 Nov 2011 15:28:01 -0500 Subject: Re: [PATCH v2 07/16] mtd/docg3: add OOB layout to mtdinfo From: Artem Bityutskiy Reply-To: dedekind1@gmail.com To: Mike Dunn Cc: Robert Jarzmik , David Woodhouse , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Ivan Djelic Date: Sun, 13 Nov 2011 22:27:50 +0200 In-Reply-To: <4EC020A2.9070003@newsguy.com> References: <1320912342-30147-1-git-send-email-robert.jarzmik@free.fr> <1320912342-30147-8-git-send-email-robert.jarzmik@free.fr> <4EBECB89.2020102@newsguy.com> <87vcqoiavr.fsf@free.fr> <1321188825.2273.4.camel@koala> <1321189398.2021.5.camel@shinybook.infradead.org> <1321191352.2273.14.camel@koala> <87ehxchta0.fsf@free.fr> <4EC020A2.9070003@newsguy.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.0.3 (3.0.3-1.fc15) Content-Transfer-Encoding: 7bit Message-ID: <1321216077.26585.11.camel@koala> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2011-11-13 at 11:55 -0800, Mike Dunn wrote: > An objection might be that mtd should not be setting policy. It's also a fairly > sizeable modification. The alternative would be to implement a mechanism to > return the corrected error count to the higher layer (e.g., ubi) for each read > operation. This would be even more work, requiring modifications to mtd and ubi. Yeah, probably just returning the ECC correction count is cleaner design. Probably we can add another argument to the mtd read function and if the return code is -EUCLEAN (correctable bit-flips happened), it would contain the highest ECC correction count encountered while reading this region of the flash. So the SW which does not care, will not require any changes. I am not sure if you'll need to mtd interfaces from mtd->func(...) to mtd_func(mtd, ...) for this or not, though. Artem.