Heavy increase in idle power between 2.6.22 and .24

[Dietz Proepper]

Hi,

some time ago I wrote the following about some experiences with 2.6.24.

> yesterday I noticed a strange behaviour regarding the 2.6.24 kernel: The
> idle power consumption went up to around 21 W, while it was around 16.5W
> with a 2.6.22 kernel with ahaci powersave patch applied. The kernel
> configuration stayed untouched.
>
> The machine is a Lenovo Z61 m.
>
> Any idea?

And recently got the time to notice the following (might already be known, 
what I found it nowhere on the website or in the mailing list ;-).

The semantics of usb autosuspend completely changed between 2.6.22 and 
2.6.23. Previousely, every usb device wos put to "automatic suspend" 
(given the right kernel build parameters ;-). But now, the only devices 
are usb hubs - which becomes a real bummer if you have one builtin hub and 
a device sitting behind it, put to "never suspend" mode... In case of the 
Z61m it's the builtin webcam (no linux driver available atm I think).
Anyway, now the machine is back to about 15.1W (kde, idle, usb devices set 
to auto-suspend, hd to min_power), which is perhaps 0.5 W more than with 
2.6.22, but that's ok for me.

How to do it by means uf udev is to create a rule for udevd like the 
following

ATTRS{idVendor}=="0c45", ATTRS{idProduct}=="627b", 
RUN+="test -e /sys/$env{DEVPATH}/power/level && { echo auto 
> /sys/$env{DEVPATH}/power/level; echo 0 
> /sys/$env{DEVPATH}/power/autosuspend; }'"

(no line breaks, replace vendor and product ID to your needs)

regards,
	Dietz