From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.233] helo=mgw-mx06.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.72 #1 (Red Hat Linux)) id 1ONjVG-0004St-4T for linux-mtd@lists.infradead.org; Sun, 13 Jun 2010 09:29:19 +0000 Subject: Re: [PATCH 1/2] mtd: OneNAND: Add runtime badblock check feature From: Artem Bityutskiy To: Joonyoung Shim In-Reply-To: <1275380256-15315-1-git-send-email-jy0922.shim@samsung.com> References: <1275380256-15315-1-git-send-email-jy0922.shim@samsung.com> Content-Type: text/plain; charset="UTF-8" Date: Sun, 13 Jun 2010 12:26:40 +0300 Message-ID: <1276421200.19028.192.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: Kyungmin Park , linux-mtd@lists.infradead.org, Thomas Gleixner Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2010-06-01 at 17:17 +0900, Joonyoung Shim wrote: > From: Kyungmin Park > > This patch is to support runtime badblock checking. This supports only > OneNAND currently. The OneNAND badblock checking when boots occurs boot > time delay. We can reduce boot time because can detect badblock at > runtime. > > Signed-off-by: Kyungmin Park Hi, this feature is interesting. But why not to use bad block table instead of adding more complexity to the already very complex and difficult to follow code? Also, if you really want this, it should be rather lazy checking, where you read OOB on demand, and then save this information to the in-ram BBT, and when you get another ->block_isbad() for a block which was previously checked, you do not read OOB for the second time. CCing Thomas, if we are lucky, he'll provide good input. -- Best Regards, Artem Bityutskiy (Артём Битюцкий)