[Bug 30570] CPU usage very high with no running tasks using it

[David Beaumont]

Public bug report changed:
https://launchpad.net/malone/bugs/30570

Description changed to:
    While my system is apparently idle (I'm not running anything that
    would hammer the CPU) there is still very high use of the CPU,
    though not by any user task. This screenshot might help explain:

    http://www.zorq.net/dump/screenshot-050206.png
    See how the CPU usage is at 70% but the total of the usage by user tasks is below 10%. top was run as a normal user, the same thing happens when run as root.

    This means that the CPU speed is kept at 2.13GHz whereas in breezy
    it would be scaled back, making the machine cooler and quieter.

    A description of my system follows, i think the only thing i changed
    from a stock install was to use the fglrx driver:

    System: Dell Inspiron 6000

    lspci:

    0000:00:00.0 Host bridge: Intel Corporation Mobile 915GM/PM/GMS/910GML Express Processor to DRAM Controller (rev 03)
    0000:00:01.0 PCI bridge: Intel Corporation Mobile 915GM/PM Express PCI Express Root Port (rev 03)
    0000:00:1d.0 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 03)
    0000:00:1d.1 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 03)
    0000:00:1d.2 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 03)
    0000:00:1d.3 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 03)
    0000:00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 03)
    0000:00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev d3)
    0000:00:1e.2 Multimedia audio controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Audio Controller (rev 03)
    0000:00:1e.3 Modem: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Modem Controller (rev 03)
    0000:00:1f.0 ISA bridge: Intel Corporation 82801FBM (ICH6M) LPC Interface Bridge (rev 03)
    0000:00:1f.2 IDE interface: Intel Corporation 82801FBM (ICH6M) SATA Controller (rev 03)
    0000:00:1f.3 SMBus: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 03)
    0000:01:00.0 VGA compatible controller: ATI Technologies Inc M22 [Radeon Mobility M300]
    0000:03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
    0000:03:01.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev b3)
    0000:03:01.1 FireWire (IEEE 1394): Ricoh Co Ltd R5C552 IEEE 1394 Controller (rev 08)
    0000:03:01.2 0805: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 17)
    0000:03:03.0 Network controller: Intel Corporation PRO/Wireless 2915ABG MiniPCI Adapter (rev 05)