From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lithops.sigma-star.at ([195.201.40.130]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fNOYc-00030d-NP for linux-mtd@lists.infradead.org; Mon, 28 May 2018 20:15:56 +0000 From: Richard Weinberger To: Mathieu Malaterre Cc: MIPS Creator CI20 Development , linux-mtd@lists.infradead.org, boris.brezillon@bootlin.com Subject: Re: ubi: refuse attaching mtd3 - MLC NAND is not supported Date: Mon, 28 May 2018 22:15:35 +0200 Message-ID: <9878779.9ArrsalhVU@blindfold> In-Reply-To: References: <2323678.8uickzfJaD@blindfold> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Mathieu, Am Freitag, 25. Mai 2018, 12:12:02 CEST schrieb Mathieu Malaterre: > > No. MLC is simply not supported and not safe to use. > > With that commit we reflect the state of the code and stop giving wrong promises. > > ACK. Would you recommend an alternate filesystem then ? There is none. One option you have is putting the MLC NAND into SLC mode, some support this. This needs to be achieved by a vendor specific command which is often undocumented. Boris and I experimented also with software SLC mode in UBI. If you want you can revive our work. > > I can hardly believe that it has been working great so far, did you > > ever do power-cut tests? > > Or are there other mechanisms on your board that make MLC usable by UBI? > > For example SLC-emulation. > > Looking quickly at the tech specs: > > https://www.elinux.org/CI20_Hardware#ROM.2FNAND > > ... > Is provided by a single Samsung K9GBG08UOA NAND flash, using an 8bit > data interface to the SoC. > ... > > So my understanding is that "it just worked" so far. I've tried > contacting some of the people involved with the design of CI20 to get > confirmation. "just worked" in terms of nobody gave it a decent testing, I fear. ;-\ Thanks, //richard