From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756166Ab3KHHM2 (ORCPT ); Fri, 8 Nov 2013 02:12:28 -0500 Received: from li42-95.members.linode.com ([209.123.162.95]:60369 "EHLO li42-95.members.linode.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752490Ab3KHHMZ convert rfc822-to-8bit (ORCPT ); Fri, 8 Nov 2013 02:12:25 -0500 Subject: Re: [PATCH 0/3 - V2] Introducing Device Tree Overlays Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Pantelis Antoniou In-Reply-To: <20131107230052.GC24450@roeck-us.net> Date: Fri, 8 Nov 2013 09:12:18 +0200 Cc: Sebastian Andrzej Siewior , Grant Likely , Rob Herring , Stephen Warren , Matt Porter , Koen Kooi , Alison Chaiken , Dinh Nguyen , Jan Lubbe , Alexander Sverdlin , Michael Stickel , Dirk Behme , Alan Tull , Sascha Hauer , Michael Bohan , Ionut Nicu , Michal Simek , Matt Ranostay , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <10734BE8-4135-4381-A6CB-478188E6E50E@antoniou-consulting.com> References: <1383676898-29819-1-git-send-email-panto@antoniou-consulting.com> <20131106190152.GA8662@breakpoint.cc> <20131106193041.GA26796@roeck-us.net> <20131106203821.GC8662@breakpoint.cc> <20131106211754.GA29300@roeck-us.net> <20131107192558.GA11453@breakpoint.cc> <4F47D5F8-F3C7-45CA-9D88-2D814BDC1BC7@antoniou-consulting.com> <20131107204626.GA11746@breakpoint.cc> <20131107230052.GC24450@roeck-us.net> To: Guenter Roeck X-Mailer: Apple Mail (2.1085) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Guenter, On Nov 8, 2013, at 1:00 AM, Guenter Roeck wrote: > On Thu, Nov 07, 2013 at 09:46:26PM +0100, Sebastian Andrzej Siewior wrote: >> On 07.11.13, Pantelis Antoniou wrote: >>> Hi Sebastian, >> Hi Pantelis, >> >>> FWIW DT has been ported to x86. And is present on arm/powerpc/mips/arc and possibly >>> others. >> >> Yes, I know. I am the one that did the work for CE4100, the first one >> that boots with DT on x86. >> >>> So what are we talking about again? If you care about the non-DT case, why >>> don't you make a patch about how you could support Guenter's use case on >>> the x86. >> >> I am only saying that this "hot-plug a device at a non hot-plugagle bus at >> runtime" is not limited to DT but this solution is. X86 + ACPI is not >> the only limitation. ARM is (forced) going to ACPI as well as far I >> know. And this solution is limited to DT. This is what I am pointing >> out. >> > I can't tell about ARM, but I am not entirely sure how ACPI support on ARM > is going to help us on powerpc. > >>> His use case is not uncommon, believe it or not, and x86 would benefit from >>> something this flexible. >> >> I *think* a more flexible solution would be something like bus_type which is >> exposed via configfs. It would be attached behind a certain device/bus where >> the "physical" hotplug interface is. The user would then be able to read the >> configuration based on whatever information he has and could then create >> devices he likes at runtime. This wouldn't depend much on the firmware that is >> used but would require a little more work I think. >> > Quite frankly, I am interested at a solution that works and solves our problems. > I am not looking for something that is 100% perfect and may never be delivered. > +1 > Fortunately, the Linux kernel was willing to adopt multiple different file > systems, and still accepts new ones on a regular basis. If a new file system > is better, it will start getting used, and old file systems are being phased out > as fewer people use them. I would hope the same should be possible with DT > overlays and possible other future solutions for the same problem, and that > we won't have to wait for the perfect solution from day 1. > Fully agreed here. I was told open source is about scratching an itch, this is worthy of scratching. > Guenter Regards -- Pantelis