Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753074Ab1BBDKg (ORCPT ); Tue, 1 Feb 2011 22:10:36 -0500 Received: from mail-iw0-f174.google.com ([209.85.214.174]:53305 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752757Ab1BBDKe convert rfc822-to-8bit (ORCPT ); Tue, 1 Feb 2011 22:10:34 -0500 MIME-Version: 1.0 In-Reply-To: <20110201103617.2c3aa118@debxo> 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> <4D4808D2.3080701@linutronix.de> <20110201103617.2c3aa118@debxo> From: Grant Likely Date: Tue, 1 Feb 2011 20:10:13 -0700 X-Google-Sender-Auth: CNIzxB5y4oPNE68MZCAcpyb7sOk Message-ID: Subject: Re: [PATCH v2 01/15] x86/e820: remove conditional early mapping in parse_e820_ext To: Andres Salomon Cc: Sebastian Andrzej Siewior , Daniel Drake , linux-kernel@vger.kernel.org, sodaville@linutronix.de, x86@kernel.org, dirk.brandewie@gmail.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2471 Lines: 71 On Tue, Feb 1, 2011 at 11:36 AM, Andres Salomon wrote: > On Tue, 01 Feb 2011 14:21:22 +0100 > Sebastian Andrzej Siewior wrote: > >> 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? >> > > That is unclear. ?For now, it's not, and there aren't plans to make it > so. > >> > >> > 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? > > No. > >> - variable initial_boot_params should be NULL in your case, right? > > Yes. > >> - 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 ... > > Perhaps it should be specifically checking for a fdt (by way of > initial_boot_params)? ? Sparc also does not have initial_boot_params, > so one might even be able to drop an #ifdef in the process. OLPC is very much the oddball in this case. Everyone else uses devicetree for registering devices. It could be solved by making OLPC explicitly register the RTC. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- 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/