From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] AHCI prefetch Date: Sat, 11 Mar 2006 19:32:19 -0500 Message-ID: <44136C13.4020002@garzik.org> References: <20060304173505.GA28643@havoc.gtf.org> <20060310043717.GA7510@htj.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.dvmed.net ([216.237.124.58]:63415 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1751354AbWCLAcV (ORCPT ); Sat, 11 Mar 2006 19:32:21 -0500 In-Reply-To: <20060310043717.GA7510@htj.dyndns.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Tejun Heo wrote: > On Sat, Mar 04, 2006 at 12:35:05PM -0500, Jeff Garzik wrote: > >>This patch has been sitting in my tmp directory for ages. >> >>We should probably turn this on, though the practical difference is >>probably minimal. >> > > > The patch works okay on my machine (ICH7R) although the patch didn't > apply to #upstream. I'm not very sure about this change though. > > 1. Why apply it only to ATAPI devices? ATA devices can benefit to. > If it's because this bit shouldn't be turned on for NCQ, we can > turn it on conditionally. We'll probably need similar condition > for ATAPI devices too if we support FIS-based PM switching. Main reason is that it will largely only have benefits on ATAPI devices, and I've only tested it on ATAPI devices. > 2. I'm a bit skeptical whether this change will bring any noticeable > performance improvement. OTOH, this seems to be a good source for Agreed. > obscure problems on some controllers which might not implement/test > this feature properly. As more controllers implement AHCI spec, > the possibility grows. Agreed. > Anyways, here's the patch regenerated against #upstream. Could I trouble you for a resend, with a proper signed-off-by and patch description? Jeff