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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 25 Feb 2008 17:42:58 -0500
From:	Jeff Garzik <jeff@...zik.org>
To:	Mark Lord <liml@....ca>
CC:	Pavel Machek <pavel@....cz>,
	kernel list <linux-kernel@...r.kernel.org>,
	Linux-pm mailing list <linux-pm@...ts.osdl.org>,
	stern@...land.harvard.edu, linux-ide@...r.kernel.org
Subject: Re: [ugly patch] Save .15W-.5W by AHCI powersaving

Mark Lord wrote:
> Pavel Machek wrote:
>> 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.
> It makes good use of AHCI-specific features.
> 
> Has it been tested with a Port-Multiplier yet?
> 
> 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.

BTW we can also save power by allowing the user to choose to disable 
hotplugging support.  Then we can power down PHYs that are not in use.

That requires the addition of some policy controls, because it is 
user-specific whether or not to waste power waiting for a plug-in event.

	Jeff



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/