Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755010AbbBFJ3G (ORCPT ); Fri, 6 Feb 2015 04:29:06 -0500 Received: from a.ns.miles-group.at ([95.130.255.143]:65275 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753338AbbBFJ3D (ORCPT ); Fri, 6 Feb 2015 04:29:03 -0500 Message-ID: <54D48955.40700@nod.at> Date: Fri, 06 Feb 2015 10:28:53 +0100 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Ricard Wanderlof , Graham Moore CC: 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 References: <1421249930-21229-1-git-send-email-dinguyen@opensource.altera.com> <54D397C8.808@opensource.altera.com> In-Reply-To: Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1651 Lines: 38 Am 06.02.2015 um 09:29 schrieb Ricard Wanderlof: > > 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). Yeah, but UBI automatically will use subpages unless you specify use the vid_hdr_offs parameter. IOW, if the driver advertises subpages UBI will use them. Thanks, //richard -- 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/