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 1gf9pk-000435-7R for linux-mtd@lists.infradead.org; Thu, 03 Jan 2019 20:43:17 +0000 From: Richard Weinberger To: Kenneth Johansson , bbrezillon@kernel.org Cc: linux-mtd@lists.infradead.org Subject: Re: [PATCH v2] mtd: rawnand: nandsim: Add support to disable subpage writes. Date: Thu, 03 Jan 2019 21:43:13 +0100 Message-ID: <6672633.KqxhzBgVKO@blindfold> In-Reply-To: <10756fcb-b284-5465-ed5c-8251cb00d9c2@kenjo.org> References: <20181222124008.28046-1-ken@kenjo.org> <10756fcb-b284-5465-ed5c-8251cb00d9c2@kenjo.org> 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: , Kenneth, Am Samstag, 22. Dezember 2018, 13:53:39 CET schrieb Kenneth Johansson: > So there was a comment from Richard on the original patch that got > mangled so it did not even have a subject line. > > The original intent for this patch was to make it possible to setup the > simulator with the same parameters as some real hardware. > That is the command "mtdinfo /dev/mtdX" would show the same on the > simulator as the real hardware. Just to make sure: nandsim simulates a given NAND chip but the simulated NAND flash controller will always be different. Think of ECC layout. In this case it may be good enough to fool your userspace, but don't count on it. > It's true that you could change the vid offset with ubiattach but that > require you know that the LEB missmatch error you get is fixed by a > different vid offset and you need to understand what that value should be. > This way you only need to match the basic mtd parameters and the rest > will just work automatically. I agree that adding a parameter to nandsim to control subpage behavior is nice. But please keep in mind that nandsim will never perfectly match your hardware. Boris, unless you have objections I'm fine to control NAND_NO_SUBPAGE_WRITE in nandsim using a module parameter. Thanks, //richard