From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from co202.xi-lite.net ([149.6.83.202]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1SRkP6-0004TT-R6 for linux-mtd@lists.infradead.org; Tue, 08 May 2012 13:24:37 +0000 Date: Tue, 8 May 2012 15:23:54 +0200 From: Ivan Djelic To: "Philip, Avinash" Subject: Re: mtd oob test is failing consistently at same places in NAND flash Message-ID: <20120508132354.GA16164@parrot.com> References: <518397C60809E147AF5323E0420B992E3E934BF1@DBDE01.ent.ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <518397C60809E147AF5323E0420B992E3E934BF1@DBDE01.ent.ti.com> Cc: "linux-mtd@lists.infradead.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, May 08, 2012 at 01:33:06PM +0100, Philip, Avinash wrote: > Hi, > > We are having an 8-bit NAND part (MT29F2G08ABAEAWP from Micron) connected to GPMC > Module (General purpose memory controller) from TI. Hi, How is ecc performed ? Using NAND internal ecc ? or with GPMC 1-bit Hamming ? 4-bit/8-bit BCH ? Which version of omap2 driver are you using ? Is OOB also ECC-protected ? > We have been seeing mtd_oobtest failure on a partition size of 248 MB. Most of > the time, test case 2 of mtd_oobtest is failing. On debugging further it seems > that bit flip is happening on the test case 2 in OOB area. It is observed that > the failure locations are consistent. If you are able to reproduce failures, then you should be able to tell which bits in OOB are failing, by adding a few debugging lines in the code. > To verify further we had tried writing zeros to OOB area and read it back. > This test is passing and confirms that all OOB bits (that are programmable) > are not bad. It does not confirm anything, bits can fail by remaining stuck at 0. BR, -- Ivan