From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933194Ab1JNP3u (ORCPT ); Fri, 14 Oct 2011 11:29:50 -0400 Received: from moutng.kundenserver.de ([212.227.17.9]:60236 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755339Ab1JNP3s (ORCPT ); Fri, 14 Oct 2011 11:29:48 -0400 From: Arnd Bergmann To: Stephen Warren Subject: Re: [PATCH] arm/tegra: select AUTO_ZRELADDR by default Date: Fri, 14 Oct 2011 17:29:41 +0200 User-Agent: KMail/1.12.2 (Linux/2.6.37; KDE/4.3.2; x86_64; ; ) Cc: "Russell King - ARM Linux" , Olof Johansson , Peter De Schrijver , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-tegra@vger.kernel.org" , "Colin Cross (ccross@android.com)" , Erik Gilling References: <1317172068-14872-1-git-send-email-pdeschrijver@nvidia.com> <20111014071500.GP21648@n2100.arm.linux.org.uk> <74CDBE0F657A3D45AFBB94109FB122FF173BE1A260@HQMAIL01.nvidia.com> In-Reply-To: <74CDBE0F657A3D45AFBB94109FB122FF173BE1A260@HQMAIL01.nvidia.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201110141729.41515.arnd@arndb.de> X-Provags-ID: V02:K0:hK4TJiqsHrhiPfc9FasvIyckgWxtLd0jpIEsH3tmqQD 4uUl2n4s1DQA/cad0KEytxvQ5HjOodNqnHsZPwDG7KtAluv1RM oaG/loVk1OxIRFISljzdvOvwU9b5c2Vd387sV+TrpgaBx/Xqr5 ELzPjl56J20YbFYDD6g7TDJ/KzEfZiSw8vgqtVn9XaPS4dPxsh JtCCob8AjZl1rCnoK664qcDGmsD5+Z7AnVuwaCtPz9bOp6CEe9 CVBsRFPewG0Si4akRhD1QUa7XAQsWrlLTSgI971tL6DdHX4OER NgcauxkRuki6xddFuBHcHO10NPt4c2GvwBFQmIZy7cxB59v3xM 5cYT4ZZN8EL//QhzlqAE= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 14 October 2011, Stephen Warren wrote: > Russell King wrote at Friday, October 14, 2011 1:15 AM: > > On Thu, Oct 13, 2011 at 04:38:46PM -0700, Olof Johansson wrote: > > > > I'll point out that this makes Tegra incompatible with ZBOOT_ROM, which > > can still be enabled. ZBOOT_ROM=y AUTO_ZRELADDR=y is an invalid > > configuration at runtime. > > I see that at least one machine solves that by doing: > > config ARCH_EP93XX > ... > select AUTO_ZRELADDR if !ZBOOT_ROM > > That said, given the way Tegra works, ZBOOT_ROM isn't useful; typically, > systems don't use NOR flash for storage of the kernel, so I don't think > ZBOOT_ROM is likely to be used. Perhaps we should just depend on !ZBOOT_ROM? That sounds like a correct fix, but also confusing because the top-level subarchitecture selection should not depend on too many things that are not obvious to someone configuring the kernel. From the perspective of least suprise I would think that instead ZBOOTROM should depend on !ARCH_TEGRA, but there is no precedent for this in the current Kconfig. You mention that tegra30 will require AUTO_ZRELADDR. Does that mean that with tegra30 merged you would no longer be able to build any tegra kernel? If not, the best solution for now would probably be to put AUTO_ZRELADDR into the defconfig for now (provided that tegra20 can still boot without it) and make tegra30 depend on AUTO_ZRELADDR within the tegra Kconfig. This is only a temporary solution I think, because it is one of the areas that we will have to revisit once we make it possible to combine multiple subarchitectures into a single kernel. I have some ideas how I would express that in Kconfig but I'm sure that we will have a lot of debate over it before we coem to a solution that works for everyone. Arnd