From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from www.osadl.org ([213.239.205.134] helo=mail.tglx.de) by pentafluge.infradead.org with esmtp (Exim 4.62 #1 (Red Hat Linux)) id 1Fnd4o-0003jx-GV for linux-mtd@lists.infradead.org; Tue, 06 Jun 2006 16:02:39 +0100 Subject: Re: NAND OOB Questions... From: Thomas Gleixner To: Steve Finney In-Reply-To: <15200571.1149603155027.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> References: <15200571.1149603155027.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Content-Type: text/plain Date: Tue, 06 Jun 2006 17:03:41 +0200 Message-Id: <1149606221.11983.47.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org Reply-To: tglx@linutronix.de List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2006-06-06 at 07:12 -0700, Steve Finney wrote: > >Yeah. I did not think about that abstruse scenario :) What the hell is > >this for ? > > Well, I didn't go looking for bugs :-). The hardware is the board I'm working on, > and what I wanted to do was force single bit errors to verify that the read correction > code worked. My way of doing that was to let the kernel write the correct ECC, > and then read it back, corrupt a single data bit, and write the data +OOB back with unchanged > OOB. It didn't work :-(. Ok. Makes sense. > As long as I'm here...is there any clever way of clearing a bad block marker? I realize > you do _not_ want to do this in the real world, but I created a few fake bad blocks for > testing purposes and there seems to be no way to get rid of them; neither Linux nor U-Boot > will let you call erase on a bad block. You can recompile U-Boot to allow it to do so, but > I'm wondering if there's any other way. Yes, switch the bad block stuff off in the kernel. :) You can do this also from your module by overriding the block_bad function. tglx