Re: Sticky IO-APIC problem

Manfred Spraul (manfred@colorfullife.com)
Wed, 04 Jul 2001 01:03:21 +0200



Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

> 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
motherboards.

> 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.

--
	Manfred
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/