Re: [patch 0/3] AHCI Link Power Management

From: Jeff Garzik
Date: Mon Jun 11 2007 - 23:18:39 EST

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.


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