From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <20006.36214.352337.659803@ipc1.ka-ro> Date: Wed, 20 Jul 2011 10:10:30 +0200 From: =?utf-8?Q?Lothar_Wa=C3=9Fmann?= To: Huang Shijie Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [i.MX28 GPMI] problem overwriting all-0xff data in NAND In-Reply-To: <4E26794D.8040004@freescale.com> References: <20004.12663.29494.339601@ipc1.ka-ro> <20110718164354.GA3328@S2100-06.ap.freescale.net> <4E26794D.8040004@freescale.com> Cc: linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Shawn Guo List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, Huang Shijie writes: > Hi Lothar: > > On Mon, Jul 18, 2011 at 03:13:27PM +0200, Lothar Waßmann wrote: > >> Hi, > >> > >> with the gpmi-nfc driver for imx28 from Shawn Guo on a TX28 I > > To be clear, the author of gpmi-nfc driver is Huang Shijie (Cc-ed). > > > > Regards, > > Shawn > > > >> encountered some problems with jffs2 when overwriting pages that have > >> been written with 0xff (e.g. from padding from the file system image > >> file). > >> > >> The problem is that the ECC info for an all-0xff block is not all-0xff > >> and thus a newly erased block is different from a block that has been > >> written with 0xff. > >> If such a block is being altered (jffs2 thinking it can simply > >> overwrite it without erasing first) the ECC information will be > >> corrupted and will produce ECC errors upon read. > >> > >> The only remedy I can think of is to prevent empty pages from actually > >> being written to flash, but leaving them in the erased state instead. > Did you mean that: > If the gpmi have to write a page which is full of 0xff, > the gpmi driver should skip the writting, and leave the page in the > erased state. > > Am I right? > Exactly. But it seems others think this should be handled by userspace tools rather than in the kernel driver. Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@karo-electronics.de ___________________________________________________________