Re: Sticky IO-APIC problem

From: Manfred Spraul (
Date: Tue Jul 03 2001 - 18:03:21 EST

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> This shows that Linux mapped the APIC (part of the processor).
> It says nothing about mapping any IO APICs (unless you deleted
> that part :).
Correct. Linux always enables the APIC, but it needs some bios tables
for the IO APIC. And the IO APIC is not present on all uniprocessor

> So, how does one know if a (UP) system has an IO APIC and that
> Linux can be configured to use the UP IO APIC code?...

Figure out which ICH is used (lspci?), then check Intel's documentation.

But even if an io apic is present, Linux can only use it if a MP table
is present. Afaik ACPI tables are not yet supported on i386, but ia64
already supports detecting the IO APIC's based on ACPI tables.

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This archive was generated by hypermail 2b29 : Sat Jul 07 2001 - 21:00:13 EST