svn commit: r191674 - in head/sys/dev/ata: . chipsets
Alexander at Leidinger.net
Wed Jun 17 13:00:26 UTC 2009
Quoting Alexander Motin <mav at FreeBSD.org> (from Wed, 29 Apr 2009
21:17:18 +0000 (UTC)):
> Author: mav
> Date: Wed Apr 29 21:17:18 2009
> New Revision: 191674
> URL: http://svn.freebsd.org/changeset/base/191674
> Add experimental support for SATA interface power management.
> Feature is controlled by hint.ata.X.pm_level tunable:
> 0 - PM disabled, old behaviour, default.
> 1 - device is allowed to initiate PM state change, host is passive.
> 2 - host initiates PARTIAL state transition every time port is idle.
> 3 - host initiates SLUMBER state transition every time port is idle.
Did I miss a man-page update for this? If yes, where is it, I would
have expected it in ata(4).
> 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
BOFH excuse #345:
Having to manually track the satellite
http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137
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