#55 Power management + BIOS not supported in 2.4

John Levon

OProfile has no support for power management
and the BIOS mode found on laptops. This means
it can crash if these features are used.

(This bug is impossible to fix on some broken


  • William Cohen

    William Cohen - 2002-09-18

    Logged In: YES

    On the Dell inspiron 4100 laptop this problem seems to be a
    result of OProfile not informing the kernel that it is using
    the APIC (Advanced Programmable Interrupt Controller). The
    newer versions of the Linux kernel (e.g. 2.4.18) have some
    support to turn off the APIC before the BIOS is used for
    power management and prevent the machine from crashing.
    However, it does not restore the APIC to the proper state
    and OProfile still does not work.

    In theory, the RTC mode should not suffer from the bad
    interaction between OProfile's use of APIC and power management.


  • John Levon

    John Levon - 2002-09-18

    Logged In: YES

    We need to use the apic_pm_register() API I believe.
    However, this
    is not exported to modules.

    More seriously, we do not use the dmi_scan blacklist so we
    will crash
    and burn horribly on laptops that /do/ have a local APIC,
    but where it
    is broken, or APM is broken.

  • John Levon

    John Levon - 2002-11-06
    • summary: Power management + BIOS not supported --> Power management + BIOS not supported in 2.4
  • John Levon

    John Levon - 2002-11-09
    • priority: 7 --> 9
  • Jerry Quinn

    Jerry Quinn - 2003-01-02

    Logged In: YES

    I may be a victim of this bug. I'm using an IBM T30 with
    debian woody, 2.4.20, and power management enabled. I
    rebuilt a kernel, built the oprofile to match. When I try
    to start oprofile, I see the following message and the
    machine locks up hard:

    /lib/modules/2.4.20-686/oprofile/oprofile.o: no local P6
    APIC. Fallinng back to RTC mode.
    Your CPU does not have a local APIC, e.g. mobile P6.
    Falling back to RTC mode.
    oprofile: can't get RTC I/O ports
    /lib/modules/2.4.20-686/oprofile/oprofile.o: init_module:
    Device or resource busy

    No messages make it to any log files.

  • Philippe Elie

    Philippe Elie - 2003-01-02

    Logged In: YES

    Your problem is different, module correctly check than your
    doesn't contain a local APIC but can't fall back to RTC mode
    because RTC is already in use: see:



  • John Levon

    John Levon - 2006-01-22

    Logged In: YES

    Not going to be fixed, document the issue in the manual instead.

  • John Levon

    John Levon - 2006-01-22
    • status: open --> closed-wont-fix

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