From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: [patch 0/4] SATA power savings patches (ALPM) Date: Mon, 09 Jul 2007 14:00:51 -0400 Message-ID: <469277D3.2020403@tmr.com> References: <20070705130357.1c172b80.kristen.c.accardi@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.tmr.com ([64.65.253.246]:34966 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753727AbXGIR5E (ORCPT ); Mon, 9 Jul 2007 13:57:04 -0400 In-Reply-To: <20070705130357.1c172b80.kristen.c.accardi@intel.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Kristen Carlson Accardi Cc: jeff@garzik.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, James.Bottomley@steeleye.com, edwintorok@gmail.com, axboe@kernel.dk, linux-scsi@vger.kernel.org Kristen Carlson Accardi wrote: > Hi Jeff, > Here's the most recent patches for ALPM. These are also located at: > http://www.kernel.org/pub/linux/kernel/people/kristen/patches/SATA/alpm > > These patches implement Aggressive Link Power management for AHCI > controllers. This feature is described in detail in the AHCI 1.x spec. > It provides power savings of anywhere from .5-1.5 Watts depending on > the system when it is enabled. (a graph demonstrating power savings > of this patch along with other power patches is located at > http://www.linuxpowertop.org/results.php for your enjoyment). > > This patch is changed from the previous version in that it incorporates all > the feedback I've gotten on the patches to date. It changes the default > of the ahci driver to be max_performance rather than min_power, so userspace > will need to explicitly enable alpm via the sysfs interface when it deems > it an appropriate time to do this. In addition, the patch was changed to > allow either HIPM or DIPM as a prerequisite for enabling ALPM, rather than > just using HIPM. > I suspect these changes would be useful for servers as well, extending run time when a failover to UPS is detected. -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot