From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vimal Singh Subject: Re: [PATCH] omap : nand : fix subpage ecc issue with prefetch Date: Fri, 6 May 2011 13:00:47 +0530 Message-ID: References: <1304334638-2198-1-git-send-email-kishore.kadiyala@ti.com> <1304621338.7222.55.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:53806 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753872Ab1EFHbI convert rfc822-to-8bit (ORCPT ); Fri, 6 May 2011 03:31:08 -0400 Received: by wya21 with SMTP id 21so2190587wya.19 for ; Fri, 06 May 2011 00:31:07 -0700 (PDT) In-Reply-To: <1304621338.7222.55.camel@localhost> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: dedekind1@gmail.com Cc: Kishore Kadiyala , linux-omap@vger.kernel.org, linux-mtd@lists.infradead.org, bdefaria@adeneo-embedded.com On Fri, May 6, 2011 at 12:18 AM, Artem Bityutskiy = wrote: > On Mon, 2011-05-02 at 16:40 +0530, Kishore Kadiyala wrote: >> For prefetch engine, read and write =A0got broken in commit '2c01946= c'. >> We never hit a scenario of not getting 'gpmc_prefetch_enable' >> call success. >> When reading/writing a subpage with a non divisible by 4 ecc number >> of bytes, the mis-aligned bytes gets handled first before enabling >> the Prefetch engine, then it reads/writes rest of the bytes. >> >> Signed-off-by: Kishore Kadiyala >> Signed-off-by: Vimal Singh >> Reported-by: Bryan DE FARIA > > This needs a better commit message with more explanation and analysis= of > the problem and how it was fixed.This commit message is not very > understandable. And then it needs also: How about a commit log like this: When reading/writing a subpage (When HW ECC is not available/enable) for number of bytes not aligned to 4, the mis-aligned bytes gets handled first (by cpu copy mathod) before enabling the Prefetch engin to/from 'p' (start of buffer 'buf'). Then it reads/writes rest of the bytes with the help of Prefetch engine, if available, or again by cpu copy mathod. Currnetly, reading/writing of rest of bytes, is not done correctly. Its trying to read/write again to/from begining of buffer 'buf', overwriting the mis-aligned bytes. =46or prefetch engine read and write it got broken in commit '2c01946c'= =2E And we never hit the scenario of not getting 'gpmc_prefetch_enable' call sucess. So, problem did not get caught up. This patch fixes the issue. > Cc: stable@kernel.org [2.6.36+] > > Right? And then we could send it upstream. Yes, sure. I think kishore can take care of adding this in 'cc' while posting next time. --=20 Regards, Vimal Singh -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html