Question about AthlonXP on nforce 2 : C2-C3 states

[Arthur Huillet <arthur.huillet@agoctrl.org>]

Hello,

I've recently discovered that my system didn't seem to go into C2/C3 states. In fact, they're not
even recognized :

# cat /proc/acpi/processor/CPU0/info 
processor id:            0
acpi id:                 0
bus mastering control:   no
power management:        no
throttling control:      no
limit interface:         no

# cat /proc/acpi/processor/CPU0/power 
active state:            C1
max_cstate:              C8
bus master activity:     00000000
states:
   *C1:                  type[C1] promotion[--] demotion[--] latency[000] usage[00000000]

Would you happen to know why the Cx states are not seen ? Also, isn't there supposed to be bus
mastering control available ? 
My mainboard is a Asus A7N8X rev 1.xx (nforce2).
The kernels I tried with no success in whatever case are 2.4.29 and 2.6.15.2.
Unfortunately, google doesn't seem to know much about this problem...

-- 
Greetings, 
A.H.