From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754015AbYE0E1Z (ORCPT ); Tue, 27 May 2008 00:27:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750819AbYE0E1P (ORCPT ); Tue, 27 May 2008 00:27:15 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:32813 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774AbYE0E1O (ORCPT ); Tue, 27 May 2008 00:27:14 -0400 Date: Mon, 26 May 2008 21:20:10 -0700 From: Arjan van de Ven To: Roland Dreier Cc: David Miller , benh@kernel.crashing.org, linux-arch@vger.kernel.org, scottwood@freescale.com, linuxppc-dev@ozlabs.org, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, tpiepho@freescale.com Subject: Re: MMIO and gcc re-ordering issue Message-ID: <20080526212010.664302cf@infradead.org> In-Reply-To: References: <1211852026.3286.36.camel@pasglop> <20080526.184047.88207142.davem@davemloft.net> <1211854540.3286.42.camel@pasglop> <20080526.192812.184590464.davem@davemloft.net> <20080526204233.75b71bb8@infradead.org> Organization: Intel X-Mailer: Claws Mail 3.3.1 (GTK+ 2.12.9; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 26 May 2008 21:08:10 -0700 Roland Dreier wrote: > > either via sparse or some fancy lockdep like "device store" thing? > > If we can't test for it and it doesn't show up on x86 ... it'll > > just be an eterrnal chase. > > Ben's point is that it will start showing up on x86 because newer > compilers are reordering things... > > - R. I know a basic reorder will show up there. A simple "barrier()" in readl/writel solves it for x86. Understandably, Ben doesn't really like that answer ;-) -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org