[ltp] Re: Fingerprint Reader -> USB -> no C3

[Florian Reitmeir]

On Sun, 24 Feb 2008, Stefan Monnier wrote:

> > hw.thinkpad_fingerprint true -> disable the reader
> > hw.thinkpad_fingerprint false -> enable the reader
> 
> Thanks: now I got my T60 down to 13W again!  It makes a 2W difference
> almost.  But in my case (Debian stock 2.6.23 kernel) putting it in
> "auto" works as well as putting it in "suspend".  Don't know why it
> isn't in "auto" in the first place since all the USB power settings in
> the /sys files seem to indicate that it's all in "autosuspend" mode.

the problem is, the kernel people did change the autosuspend policy in the
kernel .. while the core usb is autosuspend enabled, IMHO the devices are now
on a white/backlist for autosuspend (i didn't look into the kernel code)

i did notice the problem because every time regardless of my config powertop
suggested to "enable autosuspend" for usb.. and after applying the CPU did C3
again... and i really do not need the reader :-)

-- 
Florian Reitmeir