*Huge* amount of wakeups

[Rafał Krypa]

Hello,
I have seen this phenomenon several times already and want to ask you
about its cause. From time to time I am experiencing my Intel Core Duo
T2250 CPU going mad. The average wakeups per second exceeds 22k (!). 
Here comes the output of powertop -d:

PowerTOP 1.8    (C) 2007 Intel Corporation 

Collecting data for 15 seconds 
Cn                Avg residency
C0 (cpu running)        (67.3%)
C1                0.0ms ( 0.0%)
C2                0.0ms (23.4%)
C3                0.0ms ( 9.3%)
P-states (frequencies)
  1.74 Ghz     0.0%
  1333 Mhz     0.0%
  1067 Mhz     0.0%
   800 Mhz   100.0%
Wakeups-from-idle per second : 22379.8  interval: 15.0s
Power usage (ACPI estimate): 14.5W (3.5 hours) 
Top causes for wakeups:
  24.6% ( 11.5)   hald-addon-cpuf : queue_delayed_work_on
(delayed_work_timer_fn) 
  13.1% (  6.1)              Xorg : do_setitimer (it_real_fn) 
  10.4% (  4.9)       <interrupt> : extra timer interrupt 
  10.3% (  4.8)       <interrupt> : acpi 
   6.4% (  3.0)   multiload-apple : schedule_timeout (process_timeout) 
   6.3% (  2.9)     <kernel core> : queue_delayed_work_on
(delayed_work_timer_fn) 
   3.7% (  1.7)       gnome-panel : schedule_timeout (process_timeout) 
   2.4% (  1.1)       <interrupt> : eth0 
   2.3% (  1.1)              Xorg : schedule_timeout (process_timeout) 
   2.1% (  1.0)            dhcdbd : schedule_timeout (process_timeout) 
   2.1% (  1.0)   glunarclock-app : schedule_timeout (process_timeout) 
   2.1% (  1.0)    cpufreq-applet : schedule_timeout (process_timeout) 
   2.1% (  1.0)         nm-applet : schedule_timeout (process_timeout) 
(...)


As you see, no process is responsible for these wakeups. And it is not a
simple display error of powertop:

tassadar:~# cat /proc/acpi/processor/CPU0/power 
active state:            C2
max_cstate:              C8
bus master activity:     00000000
maximum allowed latency: 8000 usec
states:
    C1:                  type[C1] promotion[C2] demotion[--]
latency[001] usage[00000010] duration[00000000000000000000]
   *C2:                  type[C2] promotion[C3] demotion[C1]
latency[001] usage[1101632640] duration[00000000054670700051]
    C3:                  type[C3] promotion[--] demotion[C2]
latency[057] usage[317590412] duration[00000000103865822447]


Output for the second core is similar.
Please notice very high usage counters for C2 and C3 - and this is only
with 1 day uptime.
I am currently running 2.6.22.3 kernel (preparing for an update) but I
can remember seeing this with other kernel versions too.
The problem is unfortunately non-deterministic. This strange behavior of
CPU happens from time to time and after reboot everything is back to
normal. I cannot notice any particular actions leading into this.
Could you please help me with finding and eliminating cause of this
problem?

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