From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762916AbdDSMNg (ORCPT ); Wed, 19 Apr 2017 08:13:36 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:35064 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762858AbdDSMNe (ORCPT ); Wed, 19 Apr 2017 08:13:34 -0400 Date: Wed, 19 Apr 2017 14:13:32 +0200 From: Pavel Machek To: boris.brezillon@free-electrons.com, richard@nod.at, dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, cyrille.pitchen@atmel.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, mark.marshall@omicronenergy.com, b44839@freescale.com, prabhakar@freescale.com Subject: fsl_ifc_nand: are blank pages protected by ECC? Message-ID: <20170419121332.GA26979@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="rwEMma7ioTxnRzrJ" Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --rwEMma7ioTxnRzrJ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi! We have some problems with fsl_ifc_nand ... in the old kernels, but this one does not seem to be fixed in v4.11, either. UBIFS complains: UBIFS error (pid 931): ubifs_scan: corrupt empty space at LEB 282:252630 UBIFS error (pid 931): ubifs_scanned_corruption: corruption at LEB 282:252630 UBIFS error (pid 931): ubifs_scanned_corruption: first 1322 bytes from LEB 282:252630 UBIFS error (pid 931): ubifs_scan: LEB 282 scanning failed Possible explanation is here: https://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/289605 # I see on the forum that this issue has been raised before - my # understanding is that the omap2 nand driver does not perform ECC # detection/correction on empty pages so when UBIFS checks the empty # space data and doesn't read all 0xFF then it fails and mounts # read-only. I didn't find any good solution - only a workaround to # remove the UBIFS check.. So I checked fsl_ifc_nand.c in v4.11-rc, and yes, it seems to have the same problem: if (errors == 15) { /* * Uncorrectable error. * OK only if the whole page is blank. * * We disable ECCER reporting due to... * erratum IFC-A002770 -- so report it now if we * see an uncorrectable error in ECCSTAT. */ if (!is_blank(mtd, bufnum)) ctrl->nand_stat |= IFC_NAND_EVTER_STAT_ECCER; break; } is_blank() checks for all 0xff's, so single-bit 0xfe in the data will result in_blank() == 0 and uncorrectable error being signaled. Should the driver be modified somehow? Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html --rwEMma7ioTxnRzrJ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlj3VGwACgkQMOfwapXb+vKGzACgnx3tKXhpFJ76rCDJBQ+xWKk9 yocAni3o2lhs0GWEe8pISrcmKUoOUYjO =4p9S -----END PGP SIGNATURE----- --rwEMma7ioTxnRzrJ--