Re: 2.6.15-ck1

From: Dave Jones
Date: Thu Jan 12 2006 - 19:44:42 EST


On Thu, Jan 12, 2006 at 07:42:36PM -0500, Adam Belay wrote:

> > > It might be possible to do even a little better. Currently, I'm developing a
> > > new ACPI idle policy that tries to take advantage of the long time we may
> > > be able to spend in a C3 state.
> >
> > As soon as that usb timer hits (every 250ms iirc) you'll bounce back out
> > of any low-power state you may be in. It's a bit craptastic that we do
> > this, even if we don't have any USB devices plugged in.
>
> I agree that's annoying, but isn't 250ms not often enough to make any
> significant difference as far as power management is concerned?
> Generally some bus master activity will come along in a shorter time frame,
> causing a jump out of C3.

All I know is that when I removed the usb modules, the power usage stopped
fluctuating as often, and it spent longer times hovering around the 18-19W mark
instead of bouncing anywhere between 18-22W.

Dave

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