Messages in this thread | | | Date | Mon, 11 Jun 2007 23:12:48 -0400 | From | Jeff Garzik <> | Subject | Re: [patch 0/3] AHCI Link Power Management |
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Arjan van de Ven wrote: > Tejun Heo wrote: >> Kristen Carlson Accardi wrote: >>> Hi, >>> This series of patches enables Aggressive Link Power Management for >>> AHCI devices, as documented in the AHCI spec. On my laptop (a Lenovo >>> X60), this >>> saves me a full watt of power. On other systems, reported power savings >>> range from .5-1.5 Watts. It has been tested by the kind folks at >>> #powertop >>> with similar results. Please give it a try and let me know what you >>> think. >> >> I'm not sure about this. We need better PM framework to support >> powersaving in other controllers and some ahcis don't save much when >> only link power management is used, > > do you have data to support this? The data we have from this patch is > that it saves typically a Watt of power (depends on the machine of > course, but the range is 0.5W to 1.5W). If you want to also have an even > more agressive thing where you want to start disabling the entire > controller... I don't see how this is in conflict with saving power on > the link level by "just" enabling a hardware feature ....
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.
Jeff
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