From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756858Ab1BANV4 (ORCPT ); Tue, 1 Feb 2011 08:21:56 -0500 Received: from www.tglx.de ([62.245.132.106]:39754 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753088Ab1BANVz (ORCPT ); Tue, 1 Feb 2011 08:21:55 -0500 Message-ID: <4D4808D2.3080701@linutronix.de> Date: Tue, 01 Feb 2011 14:21:22 +0100 From: Sebastian Andrzej Siewior User-Agent: Mozilla-Thunderbird 2.0.0.24 (X11/20100329) MIME-Version: 1.0 To: Daniel Drake CC: Andres Salomon , Grant Likely , linux-kernel@vger.kernel.org, sodaville@linutronix.de, x86@kernel.org, dirk.brandewie@gmail.com Subject: Re: [PATCH v2 01/15] x86/e820: remove conditional early mapping in parse_e820_ext References: <1292600033-12271-1-git-send-email-bigeasy@linutronix.de> <1292600033-12271-2-git-send-email-bigeasy@linutronix.de> <20101230083745.GC11721@angua.secretlab.ca> <20110104130839.GA21359@www.tglx.de> <20110114081446.GC21832@angua.secretlab.ca> <20110114105709.GA7562@www.tglx.de> <20110114134345.712e2e29@queued.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Daniel Drake wrote: > Hi, Hi, > Context: https://patchwork.kernel.org/patch/450681/ > > This patch will indeed cause problems for OLPC. Thanks for bringing it > to our attention. > > On OLPC, the device tree is not used as a source of devices like on > other platforms, it is simply used to present information to the > kernel and userspace (in read-only fashion). > > If I understand it correctly, the above patch is saying: if we have a > device tree, don't add the standard x86 RTC device. Yes. > However, what we need it to say is: if we have a device tree *and* the > device tree is being used as a source of devices, don't add the > standard x86 RTC device. > > Therefore in the OLPC case, this particular bail-out condition will > never be met, because the device tree is not being used as a source of > devices. So it is not case now. Will it ever be? > > Does that make sense? I don't quite get how or what for do you use the device tree. Could you please answer me the following questions: - is the variable allnodes NULL in your case? - variable initial_boot_params should be NULL in your case, right? - how should I checked for "device tree is being used as a source of devices"? The nodes on in the device tree are not probed unless one calls of_platform_bus_probe() with a few ids. However I do this now unconditionally which is not a problem unless you have a device tree ... > Thanks, > Daniel Sebastian