Weird PCI interrupt delivery problem

[Craig Boston]

On Mon, Dec 05, 2005 at 07:51:29PM -0600, Craig Boston wrote:
> With the ACPI timer disabled (debug.acpi.disabled=timer), the ACPI+APIC
> case now behaves the same as the plain APIC case.  Each IRQ gets
> anywhere from 10,000-500,000 interrupts before it simply stops working.

And to follow up to myself yet again, the i8254 timecounter is also bad
news for APIC.  Switching to it, with or without ACPI, causes things to
stop working really fast.

Just a stab in the dark, but it sounds like there may be something
screwy going on in the interconnect between the I/O APIC and the 8259s.
I'm pretty familiar with old-style (ISA) design, but somewhat fuzzy on
exactly how those two normally coexist, especially when everything is
integrated together on a bridge chip somewhere.

IIRC there used to be some mixed-mode hacks that have been cleaned up in
6.0.  Might Windows still be doing something similar and that's why it
works?

Craig