* Ingo Molnar <mingo@elte.hu> wrote:

quoted text
> > [   27.097095] ENABLING IO-APIC IRQs
> > [   27.097287] ..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1
> > [   27.107291] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
> > [   27.107343] ...trying to set up timer (IRQ0) through the 8259A ...  failed.
> > [   27.107346] ...trying to set up timer as Virtual Wire IRQ... failed.
> > [   27.117353] ...trying to set up timer as ExtINT IRQ... works.
> > 
> > The last 4 lines above are not logged without that argument.  So my 
> > theory ATM is that this forced the kernel to initialize something in 
> > the boards registers that it does not initialize without that 
> > command, and that its going fubar as shown in the msg quoted above 
> > is a totally random thing, perhaps dependent on the phase of one of 
> > jupiters moons as to what state it powers up in.  And I got lucky, 
> > so far in that my single powerdown reset didn't trigger it again...  
> > And you _know_ what that knocking sound is by now. :)
> 
> that's weird. Could you try the hack below and _remove_ the 
> acpi_use_timer_override flag? The change should artificially cause the 
> above 4 lines to appear again, in all cases.
> 
> This would test the following aspects of your theory: is this unknown 
> side-effect of the the acpi_use_timer_override flag related to the 
> timer setup sequence in io_apic_32.c? If not, then the difference most 
> likely lies in the different ACPI setup sequence.

i tried that patch on a box here, and it produces similar 4 lines:

[    0.172141] ENABLING IO-APIC IRQs
[    0.175498] init IO_APIC IRQs
[    0.176059]  IO-APIC (apicid-pin) 2-16, 2-17, 2-18, 2-19, 2-20, 2-21, 2-22, 2-23 not connected.
[    0.187942] ..TIMER: vector=0x31 apic1=0 pin1=0 apic2=-1 pin2=-1
[    0.233859] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
[    0.236014] ...trying to set up timer (IRQ0) through the 8259A ...  failed.
[    0.236014] ...trying to set up timer as Virtual Wire IRQ... failed.
[    0.236014] ...trying to set up timer as ExtINT IRQ... works.
[    0.277879] Using local APIC timer interrupts.

but ... in all likelyhood it's some ACPI side-effects of the 
acpi_use_timer_override flag, not really this IO-APIC/timer-setup detail 
that matters.

	Ingo
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