From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from a2s40.a2hosting.com ([74.126.24.200]) by casper.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1Ntkwj-0006Ck-Qt for linux-mtd@lists.infradead.org; Mon, 22 Mar 2010 16:57:50 +0000 Received: from [207.35.173.122] (helo=[192.168.220.108]) by a2s40.a2hosting.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from ) id 1Ntkwd-0003h1-TA for linux-mtd@lists.infradead.org; Mon, 22 Mar 2010 12:57:39 -0400 Message-ID: <4BA7A183.7040206@fosstel.com> Date: Mon, 22 Mar 2010 12:57:39 -0400 From: "Pedro I. Sanchez" MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Subject: UBIFS and MLC NAND Flash Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello, I have a few questions regarding this topic. 1. The UBIFS FAQ has a summary of the state of the support for MLC NAND flash here: http://www.linux-mtd.infradead.org/faq/ubifs.html#L_ubifs_mlc The question is, is this still the case? Does the FAQ reflect the current state of affairs? 2. I have several boards with MLC NAND flash running the Linux kernel 2.6.29 and UBIFS. I am seeing a fairly large rate of file "corruption" errors, files that all of a sudden become unreadable. Curiously enough, they have been read-only files in all cases, program executables and shared libraries. Would upgrading to a more recent kernel, or back porting the latest UBIFS code, help? Shall I expect better support for MLC NAND flash in the latest UBIFS code? 3. I am also seeing other errors where it is the U-Boot or the Kernel partitions that become corrupted. UBIFS is not involved there directly since these partitions are at the mtd level and outside the UBI layer. More specifically, my flash is partitioned as mtd0, mtd1, mtd2, mtd3, mtd4. Only mtd4 has UBI/UBIFS on top. Is it possible that some flash handling problems in UBIFS (mtd4) "spill over" other non-UBIFS mtd partitions? 4. Other than minimizing flash writes, is there any other suggestion on what to do to improve on the failure rate I see in the file system? Thank you in advance, I would very much appreciate you answers. -- Pedro