[ltp] X60s USB Bus unbind for more C states..

[Jiang Qian]

On Fri, Sep 15, 2006 at 12:06:47PM +0200, Florian Reitmeir wrote:
> Hi,
> 
> like i've written before, on my X60s there is the internal USB bus which
> forces the CPU1 to C1/C2.. and there is only bluetooth and the fingerprint
> reader connected.
> 
> to disable it (and get much powersaving) use:
> 
> modprobe uhci_hcd
> modprobe ehci_hcd
> 
> cd /sys/bus/pci/drivers/uhci_hcd
> # unbind the driver from the pci device, just
> # use lspci to find one..
> # on my thinkpad its USB Bus5
> echo -n "0000:00:1d.3" >unbind 
> 
> acpitool -c will show you the nice effect..
Thanks a lot! I found it easier to just do /etc/init.d/hotplug stop
*However*, when I do(my old ubuntu hoary doesn't have acpitool)
cat /proc/acpi/processor/CPU/power

active state:            C2
max_cstate:              C8
bus master activity:     00802008
states:
    C1:                  type[C1] promotion[C2] demotion[--] latency[001] usage[00000010]
   *C2:                  type[C2] promotion[C3] demotion[C1] latency[001] usage[00102122]
    C3:                  type[C3] promotion[C4] demotion[C2] latency[085] usage[00041112]
    C4:                  type[C3] promotion[--] demotion[C3] latency[185] usage[00050198]

Sometimes it gets down to C4, but any idea why I can't get down to C8?  
I thought my max_cstate is C8!

Thanks a lot in advance.
Jiang
> 
> -- 
> Florian Reitmeir
> -- 
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