Re: Machine no longer enters C3 on 2.6.11-rc1-bk

Len Brown
2005-01-21T04:30:53Z

On Thu, 2005-01-20 at 09:32, Rich Townsend wrote:

> Gak, I just read the wiki, and USB was the culprit. But that doesn't
> explain why I'm not seeing any transitions to C1, even under full load.

This is normal for the current code -- we run C1 16 times and promote,
but if C2 latency is very low, we never demote to C1:

[root@d600 root]# cat /proc/acpi/processor/CPU0/power
active state: C4
max_cstate: C8
bus master activity: 00000000
states:
C1: type[C1] promotion[C2] demotion[--] latency[001] usage[00000010]
C2: type[C2] promotion[C3] demotion[C1] latency[001] usage[00266192]
C3: type[C3] promotion[C4] demotion[C2] latency[085] usage[00028664]
*C4: type[C3] promotion[--] demotion[C3] latency[185] usage[00359811]