svn commit: r191674 - in head/sys/dev/ata: . chipsets

Alexander Motin mav at FreeBSD.org
Thu Jun 18 13:31:24 UTC 2009


Alexander Leidinger wrote:
> Quoting Alexander Motin <mav at FreeBSD.org> (from Wed, 17 Jun 2009
> 16:10:25 +0300):
> 
>> Alexander Leidinger wrote:
>>> Quoting Alexander Motin <mav at FreeBSD.org> (from Wed, 29 Apr 2009
>>> 21:17:18 +0000 (UTC)):
> 
>>>>   PARTIAL state has up to 100us (50us for me) wakeup latency, but
>>>> for my
>>>>   ICH8M saves 0.5W of power per drive. SLUMBER state has up to 10ms
>>>> (3.5ms
>>>>   for me) wakeup latency, but saves 0.8W of power.
>>>>
>>>>   Modes 2 and 3 are implemented only for AHCI driver now.
>>>
>>> Does this mean it is for SATA devices only, or is this a feature of the
>>> complete controller (ICH5 in my case) and also works with PATA drives?
>>
>> This feature is SATA-specific by definition. AFAIK there is no bus power
>> management in PATA.
> 
> What happens if such a setting is made for a pata channel, will the
> system ignore it? The idea of the question is: can I just add those
> hints for all my ata channels on a remote system without getting into
> trouble?

You can. Nothing happen. It will just set variable that is used only by
SATA and AHCI code. PATA does not use it.

-- 
Alexander Motin


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