From: Jeff Garzik <jeff@garzik.org>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Tejun Heo <htejun@gmail.com>,
Kristen Carlson Accardi <kristen.c.accardi@intel.com>,
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
Date: Mon, 11 Jun 2007 23:18:24 -0400 [thread overview]
Message-ID: <466E1080.4070504@garzik.org> (raw)
In-Reply-To: <466E0F28.3040701@linux.intel.com>
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
next prev parent reply other threads:[~2007-06-12 3:18 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-11 18:46 [patch 0/3] AHCI Link Power Management Kristen Carlson Accardi
2007-06-12 1:58 ` Tejun Heo
2007-06-12 2:33 ` Jeff Garzik
2007-06-12 2:34 ` Arjan van de Ven
2007-06-12 3:12 ` Jeff Garzik
2007-06-12 3:12 ` Arjan van de Ven
2007-06-12 3:18 ` Jeff Garzik [this message]
2007-06-12 4:13 ` Tejun Heo
2007-06-12 4:19 ` Arjan van de Ven
2007-06-12 4:40 ` Tejun Heo
2007-06-12 15:56 ` Kristen Carlson Accardi
2007-06-12 4:43 ` Jeff Garzik
2007-06-12 15:43 ` Kristen Carlson Accardi
2007-06-13 14:51 ` Pavel Machek
2007-06-13 9:04 ` Pavel Machek
2007-06-13 16:26 ` Kristen Carlson Accardi
2007-06-14 7:56 ` Tejun Heo
2007-06-13 14:56 ` Pavel Machek
2007-06-14 11:56 ` Jens Axboe
2007-06-14 12:30 ` Tejun Heo
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