[ltp] X60s: Power drawn by audio?

[Atul Chitnis]

I just noticed that when I start playing music on my X60s (Fedora 7, 
Kernel 2.6.23.1-10.fc7, KDE with ARTS disabled), power consumption goes up 
from around 12W to more than 15W (using powertop). USB modules have been 
unloaded, and the machine is running on wireless using ATrpms' ipw3945 
drivers (the free drivers don't work for me).

I suspect something ugly in the interrupts, so here is my 
/proc/interrupts:

            CPU0       CPU1
   0:    1278565          2   IO-APIC-edge      timer
   1:       2884          0   IO-APIC-edge      i8042
   8:          3          0   IO-APIC-edge      rtc
   9:        545       4688   IO-APIC-fasteoi   acpi
  12:        150      49880   IO-APIC-edge      i8042
  14:          0          0   IO-APIC-edge      libata
  15:          0          0   IO-APIC-edge      libata
  20:          0          0   IO-APIC-fasteoi   yenta, i915@pci:0000:00:02.0
  21:     189831          0   IO-APIC-fasteoi   ipw3945, HDA Intel
  22:          0          0   IO-APIC-fasteoi   sdhci:slot0
218:          3       1414   PCI-MSI-edge      eth1
219:       6545      17477   PCI-MSI-edge      ahci
NMI:          0          0
LOC:     242456     777758
ERR:          0
MIS:          0

powertop reports:

Power usage (ACPI estimate): 15.0W (3.9 hours) (long term: 16.1W,/3.6h)

Top causes for wakeups:
   30.6% (216.1)       <interrupt> : extra timer interrupt
   24.4% (172.3)              xmms : schedule_timeout (process_timeout)
   13.4% ( 94.8)       <interrupt> : ipw3945, HDA Intel
   13.1% ( 92.6)              xmms : do_nanosleep (hrtimer_wakeup)
    6.9% ( 49.1)       S06cpuspeed : queue_delayed_work_on (delayed_work_timer_fn
    4.8% ( 34.3)              Xorg : do_setitimer (it_real_fn)
    1.1% (  8.1)         amarokapp : schedule_timeout (process_timeout)
    0.8% (  6.0)       <interrupt> : i8042
    0.6% (  4.3)              Xorg : schedule_timeout (process_timeout)
    0.6% (  4.1)           konsole : schedule_timeout (process_timeout)
    0.5% (  3.6)       firefox-bin : futex_wait (hrtimer_wakeup)

Any recommendations? I remember Rasmus Lerdorf once posting an optimized 
IRQ layoout, but for the life of me cant find it (and am unsure if they 
would work on an X60s).

TIA

Atul

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