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

From: Tejun Heo
Date: Thu Jun 14 2007 - 03:57:04 EST

Kristen Carlson Accardi wrote:
>>>>> 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?
>>> Yeah, it was some Lenovo notebook. Pavel is more familiar with the
>>> hardware. Pavel, what was the notebook which didn't save much power
>>> with standard SATA power save but needed port to be completely turned off?
>> Thinkpad x60. Some one Kristen probably used while developing the
>> patch :-).
> Yes - that confirms my conclusion that the first patch just wasn't
> done correctly - cause when I measure the power savings with a power
> meter on the X60 with my patches I see ~ 1W.

Hmmm... Could it be that the controller doesn't enter powersave state
when SControl is written to?

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