From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753561AbXKSVoU (ORCPT ); Mon, 19 Nov 2007 16:44:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751750AbXKSVoK (ORCPT ); Mon, 19 Nov 2007 16:44:10 -0500 Received: from sj-iport-3-in.cisco.com ([171.71.176.72]:60708 "EHLO sj-iport-3.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751652AbXKSVoI (ORCPT ); Mon, 19 Nov 2007 16:44:08 -0500 To: benh@kernel.crashing.org Cc: James Bottomley , Linux Kernel list , linux-scsi , Russell King Subject: Re: SCSI breakage on non-cache coherent architectures X-Message-Flag: Warning: May contain useful information References: <1195450523.7022.37.camel@pasglop> From: Roland Dreier Date: Mon, 19 Nov 2007 13:43:59 -0800 In-Reply-To: <1195450523.7022.37.camel@pasglop> (Benjamin Herrenschmidt's message of "Mon, 19 Nov 2007 16:35:23 +1100") Message-ID: User-Agent: Gnus/5.1008 (Gnus v5.10.8) XEmacs/21.4.20 (linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 19 Nov 2007 21:43:59.0780 (UTC) FILETIME=[4B3E7E40:01C82AF5] Authentication-Results: sj-dkim-3; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com/sjdkim3002 verified; ); Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > I've been debugging various issues on the PowerPC 44x embedded > architecture which happens to have non-coherent PCI DMA. > > One of the problem I'm hitting is that one really need to enforce > kmalloc alignement to cache lines or bad things will happen (among > others with USB), for some reasons, powerpc failed to do so, I fixed it. Heh... I hit the same problem literally 5 years ago: http://lwn.net/Articles/1783/ I implemented the __dma_buffer annotation: http://lwn.net/Articles/2269/ But DaveM said we should just use the PCI pool code instead: http://lwn.net/Articles/2270/ - R.