Re: [ugly patch] Save .15W-.5W by AHCI powersaving

From: Pavel Machek
Date: Mon Feb 25 2008 - 17:34:36 EST


Hi!

>> This is a patch (very ugly, assumes you have just one disk) to bring
>> powersaving to AHCI. You need Alan's SCSI autosuspend (attached) patch
>> as a base.
>>
>> It saves .5W compared to config with disk spinning, and even .15W
>> compared to hdparm -y... on my thinkpad x60 anyway.
> ..
>
> There was a discussion of this here today.

Real-life discussion, or something I could read? :-).

> It makes good use of AHCI-specific features.
>
> Has it been tested with a Port-Multiplier yet?

I do not know what port-multiplier is, sorry. But it was not really
tested. It is not expected to work on any other config than notebook
very similar to mine.

> This is cool enough that we really ought to do a hardware-independent
> version, so that all SATA interfaces could benefit. Especially ata_piix,
> but others too.

Well, it seems like it is 10 lines per driver once Alan's SCSI
autosuspend patches are in...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/