From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp1.ascom-ws.com ([195.81.148.76] helo=mail.ascom-ws.com) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1c04M1-00032O-Nj for linux-mtd@lists.infradead.org; Fri, 28 Oct 2016 10:25:46 +0000 From: Danesh Daroui To: Boris Brezillon , Steve deRosier CC: "linux-mtd@lists.infradead.org" Subject: RE: OOB Test fails Date: Fri, 28 Oct 2016 10:23:47 +0000 Message-ID: <39BC08CB3FF4C84CB6397533D4FC79095770D803@SEGOTEXCH02.ascom-Resource.ads> References: <39BC08CB3FF4C84CB6397533D4FC79095770D513@SEGOTEXCH02.ascom-Resource.ads> <20161027093407.53a76657@bbrezillon> <20161027174527.6003fd37@bbrezillon> In-Reply-To: <20161027174527.6003fd37@bbrezillon> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Boris, I have one question and would appreciate if you can assist me with that. As= I wrote we are using a Micron NAND 1GiB 3,3V 8-bit flash memory with UBIFS= where we experience some problems. I am wondering whether there are specif= ic drivers provided by vendor in this case or there are generic drivers wit= h respect to the hardware architecture given to the Kernel that can be used= as we probably did in this case? I have downloaded a driver package from M= icron which is apparently written for our NAND flash memory but the driver = uses lots of read/write functions which are platform dependent and not impl= emented in the driver which makes sense though. Would you please advise and let us know if we are on the right track e.g. u= sing the driver with the kernel or we need to find more specific driver so = the problem that we face now can be related to incorrect driver? Regards, Danesh Daroui -----Original Message----- From: Boris Brezillon [mailto:boris.brezillon@free-electrons.com]=20 Sent: den 27 oktober 2016 17:45 To: Steve deRosier Cc: Danesh Daroui ; linux-mtd@lists.infradead.org Subject: Re: OOB Test fails On Thu, 27 Oct 2016 09:34:07 +0200 Boris Brezillon wrote: > Hi Steve, >=20 > On Wed, 26 Oct 2016 09:16:42 -0700 > Steve deRosier wrote: >=20 > > Hi Danesh, > >=20 > >=20 > > On Wed, Oct 26, 2016 at 9:07 AM, Danesh Daroui wrote: =20 > > > Hello all, > > > > > > I have executed MTD tests against an unmounted MTD device which uses = UBIFS. All MTD tests except OOB test is passed where the OOB test fails fro= m time to time and from device to device. I have read here: > > > > > > http://www.linux-mtd.infradead.org/faq/ubi.html#L_why_no_oob > > > > > > that UBIFS does not use OOB area. Therefore wanted to ask if failing = this test does not need that there is any problem in our system (both HW an= d SW/configuration) and we can safely ignore the results for this test. > > > =20 > >=20 > > UBIFS doesn't use the OOB area, but your MTD driver most likely does. > > We don't want UBI or UBIFS messing with the OOB area because your=20 > > flash, NAND controller and the MTD driver will use that. Bad block=20 > > markers are set in the OOB area by the manufacturer in most NAND=20 > > flashes and your controller and MTD driver will store and use the=20 > > bits in the OOB to do error correction. > >=20 > > So, in short - the OOB area does need to function correctly. As to=20 > > if and why the OOB test is or isn't working is a different issue and=20 > > I have no input on that. All that depends on your mix of flash,=20 > > controller and driver. My bad, I misread your sentence. I thought you we saying "the OOB area does= *not* need to function correctly". My apologies for this misunderstanding, it seems we're on the same page.