From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-in-02.arcor-online.net (mail-in-02.arcor-online.net [151.189.21.42]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.arcor.de", Issuer "Thawte Premium Server CA" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 0A08BDDD0A for ; Thu, 15 Feb 2007 13:43:13 +1100 (EST) In-Reply-To: <17875.49565.444870.924729@cargo.ozlabs.ibm.com> References: <20070213060904.GA6214@localhost.localdomain> <20070213061026.5837FDDDE9@ozlabs.org> <9696D7A991D0824DBA8DFAC74A9C5FA302A1B705@az33exm25.fsl.freescale.net> <1171470754.4003.101.camel@zod.rchland.ibm.com> <6206de08b7f12175bebe669291c66334@kernel.crashing.org> <9696D7A991D0824DBA8DFAC74A9C5FA302A1B86F@az33exm25.fsl.freescale.net> <9df9bf3adf511f4c1a7945e022fdd447@kernel.crashing.org> <9696D7A991D0824DBA8DFAC74A9C5FA302A1B8EF@az33exm25.fsl.freescale.net> <1171489360.20192.184.camel@localhost.localdomain> <122a66d49480520cf87cd748bbfc50bb@kernel.crashing.org> <17875.49565.444870.924729@cargo.ozlabs.ibm.com> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <6c90a73251f09d619498c77264a15fef@kernel.crashing.org> From: Segher Boessenkool Subject: Re: [PATCH 15/16] Add device tree for Ebony Date: Thu, 15 Feb 2007 03:43:05 +0100 To: Paul Mackerras Cc: David Gibson , Yoder Stuart-B08248 , linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , >> Exactly. The "separate device tree" imitates a real OF, >> so you will lose much of its value if you start to deviate >> from how real OF works. > > I disagree. It was never (and isn't now) the intention to put all of > the OF requirements on the device tree supplied on OF-less systems. That's not my point; I'm saying that you shouldn't do the same (or similar) things in different ways than "real OF" does. > In other words, "we should do X because the bindings require it" isn't > of itself an argument for making X a requirement on the device tree. It's a pretty strong indicator though; all other things being equal, you should do what the bindings say. There can be good reasons to do differently, but then you better have those reasons :-) > "We should do X because there are good technical reasons for doing it > that way" is. "We should do X because if we don't then device trees > from real OF systems won't be compatible" is also a reasonable > argument. You're turning the argument around, but hey :-) > The device tree is required because it is a flexible way to give > useful information to the kernel. Thus the focus is quite properly on > what is useful (or at least potentially useful) to the Linux kernel, > not on what some binding document says. Still, if you want to be compatible to "real OF" (and you do, otherwise you would have chosen a structure that is more appropriate for this goal), you better *be* compatible to OF. Segher