Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757759AbXFLDSi (ORCPT ); Mon, 11 Jun 2007 23:18:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753007AbXFLDS2 (ORCPT ); Mon, 11 Jun 2007 23:18:28 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:51143 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752581AbXFLDS1 (ORCPT ); Mon, 11 Jun 2007 23:18:27 -0400 Message-ID: <466E1080.4070504@garzik.org> Date: Mon, 11 Jun 2007 23:18:24 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.12 (X11/20070530) MIME-Version: 1.0 To: Arjan van de Ven CC: Tejun Heo , Kristen Carlson Accardi , james.bottomley@steeleye.com, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch 0/3] AHCI Link Power Management References: <20070611114600.7fca1c24.kristen.c.accardi@intel.com> <466DFDB5.9030901@gmail.com> <466E0642.5020506@linux.intel.com> <466E0F30.3000700@garzik.org> <466E0F28.3040701@linux.intel.com> In-Reply-To: <466E0F28.3040701@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.8 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1065 Lines: 26 Arjan van de Ven wrote: > Jeff Garzik wrote: >> SATA standard defines lower power phy states. So the same argument >> you're using for AHCI applies there too -- "just" enabling an existing >> hardware feature. > yes I'm not arguing against that. I was trying to find out (and > suggest-unless-proven-otherwise) that the 2 are not exclusive or > conflicting... in fact I assume both are wanted concurrently. Yes and no. As I understand it, AHCI's capability is an automatic version of what standard SATA phys provide manually. In AHCI's case, the hardware automatically manages the link power, possibly cycling it hundreds of times per second. In the standard case, software must determine when a different power state is appropriate based on current conditions, and update the phy appropriately. Jeff - 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/