From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx.dave-tech.it ([2.229.21.40]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YVInk-0001ZJ-AO for linux-mtd@lists.infradead.org; Tue, 10 Mar 2015 11:58:21 +0000 Received: from [127.0.0.1] (unknown [192.168.0.126]) by mx.dave-tech.it (Postfix) with ESMTPS id 25E2695 for ; Tue, 10 Mar 2015 12:57:54 +0100 (CET) Message-ID: <54FEDC42.2060407@dave-tech.it> Date: Tue, 10 Mar 2015 12:57:54 +0100 From: Andrea Scian MIME-Version: 1.0 To: mtd_mailinglist Subject: RFC: detect and manage power cut on MLC NAND Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Dear All, for testing and research purpose, I'm working with an Embedded Linux product which mounts an MLC NAND. I know that one of the trouble with MLC flash on Linux with UBI/UBIFS is the power cut management (ref. http://www.linux-mtd.infradead.org/doc/ubifs.html#L_unstable_bits) IIUC the solution inside MTD/UBI/UBIFS is not so simple and thus not so quick to implement. I'm wondering if anyone of you already think about managing power cut in a different way: many embedded/industrial products already have some big/huge bypass capacitor that are able to keep the system alive for hundreds of milliseconds (this is useful for power supply micro-interruptions), which are commonly enough to complete the latest NAND operation. Most of the has a GPIO/IRQ that tells whenever such a power cut happens, so the kernel can take some actions with it (e.g., in our case, complete the last NAND operation and prevent from starting newer operation, which may corrupt the NAND pages). WDYT about this? If it sounds reasonable is there any suggestion where to place such a code? Best Regards, -- Andrea SCIAN DAVE Embedded Systems