On an Intel SCB2, the ACPI SCI in IOAPIC mode is to IRQ31,
which turns out to be pin 15 of the 2nd IOAPIC.
But this causes pin15 on the 1st IOAPIC to not get initialized with
an identify mapping because that code doesn't expect an override
to be to an IOAPIC other than the 1st.
Created attachment 3080 [details]
This patch checks that (mp_irqs[idx].mpc_dstapic == ioapic)
before accepting that an interrupt source override should
disqualify a legacy identity mapping. 2.6 needs the same.
This patch causes severe problems on at least some x86_64 and i386 systems: the
clock ticks twice as fast -- see, for example, http://lkml.org/lkml/2004/6/20/57
bad fix was made into good fix
linux-acpi-release-2.6.7 on the way to 2.6.8:
*** Bug 2927 has been marked as a duplicate of this bug. ***