Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758741AbZD0TsV (ORCPT ); Mon, 27 Apr 2009 15:48:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752675AbZD0TsL (ORCPT ); Mon, 27 Apr 2009 15:48:11 -0400 Received: from ovro.ovro.caltech.edu ([192.100.16.2]:52987 "EHLO ovro.ovro.caltech.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750963AbZD0TsL (ORCPT ); Mon, 27 Apr 2009 15:48:11 -0400 Message-ID: <49F60BF8.8040404@ovro.caltech.edu> Date: Mon, 27 Apr 2009 12:48:08 -0700 From: David Hawkins User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: Timur Tabi CC: linuxppc-dev@ozlabs.org, Dan Williams , Liu Dave-R63238 , linux-kernel@vger.kernel.org, Ira Snyder Subject: Re: [PATCH] fsldma: use PCI Read Multiple command References: <20090424183517.GB23140@ovro.caltech.edu> <49F608B7.9080409@ovro.caltech.edu> <49F60A3A.4060402@freescale.com> In-Reply-To: <49F60A3A.4060402@freescale.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (ovro.ovro.caltech.edu); Mon, 27 Apr 2009 12:48:10 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1186 Lines: 36 >> Would you like some sort of summary of this info for a commit >> message? > > That's probably overkill. I just want a sentence or two that tells > someone looking at the code casually that the behavior of reading PCI > memory might be different than what they expect. Ok, will-do. >> Would you like us to check any other transaction/register combos? > > Yes, could you try this on non-PCI memory? We've been using it to DMA between the x86 host main memory and the MPC8349EA boards (PCI targets). The reason we changed to Read Multiple was that it had a dramatic improvement in efficiency through bridges. However, the x86 host memory is prefetchable, so is consistent with the use of Read Multiple. Can you give me an example of non-PCI memory that would be non-prefetchable that you'd like us to try? We can see if our host CPUs have an area like that ... we just need to know what device to look for first :) Cheers, Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/