From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932668Ab0JHT6t (ORCPT ); Fri, 8 Oct 2010 15:58:49 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:41228 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754651Ab0JHT6s (ORCPT ); Fri, 8 Oct 2010 15:58:48 -0400 Date: Fri, 8 Oct 2010 12:58:03 -0700 From: Andrew Morton To: Russell King - ARM Linux Cc: Felipe Contreras , linux-main , linux-arm , Arnd Hannemann , Han Jonghun , Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , Hemant Pedanekar Subject: Re: [PATCH] ARM: allow, but warn, when issuing ioremap() on RAM Message-Id: <20101008125803.e5bc7306.akpm@linux-foundation.org> In-Reply-To: <20101007192245.GC26435@n2100.arm.linux.org.uk> References: <1286444662-16843-1-git-send-email-felipe.contreras@gmail.com> <20101007192245.GC26435@n2100.arm.linux.org.uk> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 7 Oct 2010 20:22:45 +0100 Russell King - ARM Linux wrote: > On Thu, Oct 07, 2010 at 12:44:22PM +0300, Felipe Contreras wrote: > > Many drivers are broken, and there's no alternative in sight. Such a big > > change should stay as a warning for now, and only later should it > > actually fail. > > > > The drivers are not doing something correct, we get it, but for now it's > > better to allow them to work (they do 99% of the time anyway) rather > > than to force everyone to revert this patch in their internal trees > > until there's a solution. A slightly broken functionality is better than > > no functionality at all. > > > > A warning lets people know that what they are doing is not right, and > > they should fix it. > > So what are _you_ going to do to fix these drivers? Continue reverting > this patch? Or are you just going to ignore the issue entirely? > > Unless people can come up with a plan to fix their drivers using ioremap > on system RAM thereby violating the architecture specification, I'm > _not_ going to apply this patch. We *do* have a plan: as of 2.6.36, the kernel will emit a WARN_ON trace when a driver does this. Offending code will be discovered, developers will get bug reports from worried users, etc. This is usually pretty effective.