Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754783AbbBFI3p (ORCPT ); Fri, 6 Feb 2015 03:29:45 -0500 Received: from bes.se.axis.com ([195.60.68.10]:49913 "EHLO bes.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754662AbbBFI3o (ORCPT ); Fri, 6 Feb 2015 03:29:44 -0500 Date: Fri, 6 Feb 2015 09:29:40 +0100 From: Ricard Wanderlof X-X-Sender: ricardw@lnxricardw1.se.axis.com To: Graham Moore CC: Richard Weinberger , Dinh Nguyen , Josh Triplett , Linux List , "yamada.m@jp.panasonic.com" , "linux-mtd@lists.infradead.org" , Dinh Nguyen , Brian Norris , David Woodhouse Subject: Re: [PATCH] mtd: denali: Disable sub-page writes in Denali NAND driver In-Reply-To: <54D397C8.808@opensource.altera.com> Message-ID: References: <1421249930-21229-1-git-send-email-dinguyen@opensource.altera.com> <54D397C8.808@opensource.altera.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1598 Lines: 36 On Thu, 5 Feb 2015, Graham Moore wrote: > Actually, we made this change to make UBIFS work. So, yes, the driver > never worked for UBI. Worked fine for JFFS2, raw data. > > A customer reported an issue with ECC errors when using UBIFS on NAND > flash with Altera SoC. > > We debugged it and found the ECC errors occur because the UBI subsystem > is trying to write sub-pages in the NAND, but neither the NAND chip > itself nor the Denali NAND controller support sub-page writes. Just a bit curious. It is not uncommon for controllers or chips not to support sub-page writes. In that case however, the partition(s) used by UBI should be formatted accordingly, i.e. using the appropriate --sub-page-size argument to ubiformat (when formatting partitions on the system itself), or the corresponding argument to ubinize (when preparing images offline). If that is done correctly, then the lack of subpage write capability is not a problem per se (of course, the UBI EC and VID headers then take up more space so less space is available for user data; on a flash with 2k pages it is only 2k bytes per LEB that is lost however). /Ricard -- Ricard Wolf Wanderl?f ricardw(at)axis.com Axis Communications AB, Lund, Sweden www.axis.com Phone +46 46 272 2016 Fax +46 46 13 61 30 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/