Re: [PATCH 3/3] libata: Change medium_power LPM policy to match Intel recommendations

[Tejun Heo]

On Sat, Apr 18, 2015 at 08:26:36AM -0700, Matthew Garrett wrote:
> Intel publish a document on designing energy efficient SATA devices at
> http://www.intel.com/content/dam/doc/reference-guide/sata-devices-implementation-recommendations.pdf
> which recommends that ALPE be set, ASPE be cleared and that DIPM be enabled
> on the device. Right now we have no policy that matches that - medium_power
> does not enable DIPM and min_power sets ASPE. Change medium_power to
> implement these recommendations, with the addition of devslp state being
> inherited from the initial configuration. With luck this will provide
> reasonable power savings without causing the device breakages we
> occasionally see with the min_power policy.

Can we add comment explaining what med_power implements and link to
the above?

Thanks.

-- 
tejun
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