[ltp] CPU Idle and whine

[Richard Neill]

igorr+tp@ifi.uio.no wrote:
> on Feb 5, 2006, 20:13, Richard Neill wrote:
> 
>> I noticed that there is a faint(*) whine audible through the speakers 
>> of the Thinkpad. It only occurs when the system is idle, so I think it 
>> is caused by the CPU idle state [kernel 2.6,ACPI].

> 
> ThinkWiki has some insights. A few things worth considering:
> 
> 1) Setting cstate to C3 or C2. It's bad because the power is drained.
> 2) Unloading uhci_hcd (if you don't need USB devices)
> 3) Undervolting
> 

Thank you.

1) I tried removing the processor and thermal modules. This does fix the 
problem. What am I losing by doing this?


2)Alternatively, I looked at
  /proc/acpi/processor/CPU/power
and the machine switches between C1 when idle and C2 when busy. It never 
reaches C3, and no other levels are listed.
Changing the value of
  /sys/module/processor/parameters/max_cstate
has no effect.

3)Removing uhci_hcd doesn't make any difference.

Thanks,

Richard