From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from down.free-electrons.com ([37.187.137.238] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZhBuO-0001oY-Th for linux-mtd@lists.infradead.org; Wed, 30 Sep 2015 07:34:37 +0000 Date: Wed, 30 Sep 2015 09:33:55 +0200 From: Boris Brezillon To: "Bean Huo =?UTF-8?B?6ZyN5paM5paM?= (beanhuo)" Cc: Richard Weinberger , "dedekind1@gmail.com" , "adrian.hunter@intel.com" , "computersforpeace@gmail.com" , "baruch@tkos.co.il" , "asierra@xes-inc.com" , "guz.fnst@cn.fujitsu.com" , "gsi@denx.de" , David Woodhouse , "linux-mtd@lists.infradead.org" , "Frank Liu =?UTF-8?B?5YiY576k?= (frankliu)" , Andrea Scian , "Karl Zhang =?UTF-8?B?5byg5Y+M6ZSj?= (karlzhang)" , Iwo Mergler , "Jeff Lauruhn (jlauruhn)" , Stefan Roese , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 0/9] drivers:mtd:UBI: add bakvol module for MLC NAND paired page issue Message-ID: <20150930093355.3266a4b3@bbrezillon> In-Reply-To: References: <560A59B8.4000701@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 30 Sep 2015 05:31:43 +0000 Bean Huo =E9=9C=8D=E6=96=8C=E6=96=8C (beanhuo) wrote: > > Am 28.09.2015 um 09:02 schrieb Bean Huo =E9=9C=8D=E6=96=8C=E6=96=8C (be= anhuo): > > > Hello, > > > > > > This series aims at adding a bakvol module for MLC NAND paired page > > > Power loss protection. > > > MLC NAND paired page power loss is a known issue so far, MLC NAND > > > pages are coupled in a sense that if you cut power while writing to a > > > page, you corrupt not only this page, but also one of the previous pa= ges > > which is paired with the current one. > > > Currently, there is no a perfect solution for this. > > > This paired page solution is based on NAND multiple plane program > > > feature. For this Patch, only used dual plane page program, means two > > > different plane pages can Be programmed together at the same time. > > > Dual plane page program only implements in backup operation. Only > > > lower page data Be duplicated and back up into a internal log volume = by > > dual plane program method. > > > > > > This patch has been testing on Micron 70s/80s/90s MLC NAND. > > > Of course there are some places needed to be improved and simplified. > > > > > > Any suggestion and comments welcomed. > >=20 > > As stated before, using OOB in UBI is not going to happen unless proven= that > > there is absolutely no other way to solve the paired pages problem. > >=20 > > Nacked-by: Richard Weinberger > >=20 > > Sorry, > > //Richard >=20 > Hi, Richard > Thanks for your concern. I am a new patch submitter. > Can you tell me Nacked-by means? >=20 > By the way, Do you review my patches series ? I don't backup duplicated d= ata in OOB . That's not what Richard said, he just pointed that you were using the OOB area, and you're actually using it to store the information about which page you're backuping. > Can you specify which sector codes ? so that I can explain it in detail. And as answered by Richard, check_original_data() and mtd_write_dual_plane_oob() are filling the OOB buf with the original page offset, so you're definitely using the OOB area to store metadata. --=20 Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com