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From: Bill Davidsen <davidsen@tmr.com>
To: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
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
Subject: Re: [patch 0/4] SATA power savings patches (ALPM)
Date: Mon, 09 Jul 2007 14:00:51 -0400	[thread overview]
Message-ID: <469277D3.2020403@tmr.com> (raw)
In-Reply-To: <20070705130357.1c172b80.kristen.c.accardi@intel.com>

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 <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

      reply	other threads:[~2007-07-09 17:57 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-05 20:03 [patch 0/4] SATA power savings patches (ALPM) Kristen Carlson Accardi
2007-07-09 18:00 ` Bill Davidsen [this message]

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