Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757919Ab3GYSx4 (ORCPT ); Thu, 25 Jul 2013 14:53:56 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:38442 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756849Ab3GYSxx (ORCPT ); Thu, 25 Jul 2013 14:53:53 -0400 Message-ID: <51F1743D.7050007@wwwdotorg.org> Date: Thu, 25 Jul 2013 11:53:49 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Richard Cochran CC: Mark Rutland , Olof Johansson , Catalin Marinas , "devicetree@vger.kernel.org" , "ksummit-2013-discuss@lists.linuxfoundation.org" , Russell King - ARM Linux , Samuel Ortiz , Domenico Andreoli , "linux-kernel@vger.kernel.org" , Dave P Martin , "linux-arm-kernel@lists.infradead.org" , "rob.herring@calxeda.com" , Pawel Moll , Ian Campbell Subject: Re: DT bindings as ABI [was: Do we have people interested in device tree janitoring / cleanup?] References: <20130725175702.GC22291@e106331-lin.cambridge.arm.com> <51F168FC.9070906@wwwdotorg.org> <20130725182920.GA24955@e106331-lin.cambridge.arm.com> <20130725184834.GA8296@netboy> In-Reply-To: <20130725184834.GA8296@netboy> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1701 Lines: 36 On 07/25/2013 11:48 AM, Richard Cochran wrote: > On Thu, Jul 25, 2013 at 07:29:20PM +0100, Mark Rutland wrote: >> On Thu, Jul 25, 2013 at 07:05:48PM +0100, Stephen Warren wrote: >>> >>> I don't think having people "rely" on the bindings is the issue so much >>> as the awareness that if they do, there will be compatibility issues for >>> unstable bindings. >> >> As long as we can make sufficiently clear that trying to use an unstable >> binding is going to be *very* painful, and not necessarily supported. > > Oh, man. > > The introduction of DT into ARM Linux was supposed to make everyone's > life sooo much easier. Of course, based on experience with powerpc, I > never believed it*, but still I would expect to hear that the DT > bindings are, well, a *binding* contract between the board developer, > boot loader, and the kernel. > > Once it is working with a particular kernel, a DT board description > file should continue to work indefinitely with newer kernels. Anything > less is a regression, pure and simple. > > If you go around changing the bindings willy nilly, then what is point > of having DT at all? That's exactly why we're starting to think about which bindings should be considered stable and immutable, and when that should happen. As Olof pointed out, we haven't fully enforced that yet. Preferably bindings will be marked stable very fast, but mistakes are always going to happen in early development. ABIs are very hard. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/