From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765690AbYBZVsw (ORCPT ); Tue, 26 Feb 2008 16:48:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763145AbYBZVsn (ORCPT ); Tue, 26 Feb 2008 16:48:43 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:33904 "EHLO gprs189-60.eurotel.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762868AbYBZVsm (ORCPT ); Tue, 26 Feb 2008 16:48:42 -0500 Date: Tue, 26 Feb 2008 22:49:08 +0100 From: Pavel Machek To: Mark Lord Cc: Mark Lord , kernel list , Linux-pm mailing list , stern@rowland.harvard.edu, linux-ide@vger.kernel.org Subject: Re: [ugly patch] Save .15W-.5W by AHCI powersaving Message-ID: <20080226214908.GC10280@elf.ucw.cz> References: <20080225134558.GA1611@elf.ucw.cz> <47C34081.5090205@rtr.ca> <20080225223432.GN2659@elf.ucw.cz> <47C435C4.9000402@rtr.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47C435C4.9000402@rtr.ca> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 2008-02-26 10:52:36, Mark Lord wrote: > 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. Yep, I seen that, too. I'm just afraid to check, maybe AHCI powerdown does not save that much power when links in powersave already... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html