From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [ugly patch] Save .15W-.5W by AHCI powersaving Date: Tue, 26 Feb 2008 10:52:36 -0500 Message-ID: <47C435C4.9000402@rtr.ca> References: <20080225134558.GA1611@elf.ucw.cz> <47C34081.5090205@rtr.ca> <20080225223432.GN2659@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([76.10.145.34]:3478 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763248AbYBZPtl (ORCPT ); Tue, 26 Feb 2008 10:49:41 -0500 In-Reply-To: <20080225223432.GN2659@elf.ucw.cz> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Pavel Machek Cc: Mark Lord , kernel list , Linux-pm mailing list , stern@rowland.harvard.edu, linux-ide@vger.kernel.org Pavel Machek wrote: > Hi! > >>> This is a patch (very ugly, assumes you have just one disk) to bring >>> powersaving to AHCI. You need Alan's SCSI autosuspend (attached) patch >>> as a base. >>> >>> It saves .5W compared to config with disk spinning, and even .15W >>> compared to hdparm -y... on my thinkpad x60 anyway. >> .. >> >> There was a discussion of this here today. > > Real-life discussion, or something I could read? :-). > >> It makes good use of AHCI-specific features. >> >> Has it been tested with a Port-Multiplier yet? > > I do not know what port-multiplier is, sorry. But it was not really > tested. It is not expected to work on any other config than notebook > very similar to mine. > >> This is cool enough that we really ought to do a hardware-independent >> version, so that all SATA interfaces could benefit. Especially ata_piix, >> but others too. > > Well, it seems like it is 10 lines per driver once Alan's SCSI > autosuspend patches are in... .. Cool (literally)! I think I might have gotten your patch confused in my mind with another AHCI patch, which uses features of the chip itself to automatically negotiate/change link power status on the fly (no s/w needed, other than to turn it on). That one is very ACPI specific, though.