From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([66.187.233.31]:59561 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1752146AbWCJAsa (ORCPT ); Thu, 9 Mar 2006 19:48:30 -0500 Date: Thu, 9 Mar 2006 19:48:15 -0500 From: Alan Cox Subject: Re: [PATCH] Document Linux's memory barriers [try #4] Message-ID: <20060310004815.GD24904@devserv.devel.redhat.com> References: <16835.1141936162@warthog.cambridge.redhat.com> <17424.48029.481013.502855@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17424.48029.481013.502855@cargo.ozlabs.ibm.com> Sender: linux-arch-owner@vger.kernel.org To: Paul Mackerras Cc: David Howells , torvalds@osdl.org, akpm@osdl.org, mingo@redhat.com, alan@redhat.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org List-ID: On Fri, Mar 10, 2006 at 10:34:53AM +1100, Paul Mackerras wrote: > MMIO accesses are done under a spinlock, and that if your driver is > missing them then that is a bug. I don't think it makes sense to say > that mmiowb is required "on some systems". Agreed. But if it is missing it may not be a bug. It depends what the lock actually protects.