Subject: Re: 3Com ep0
To: , <>
From: David Laight <>
List: tech-smp
Date: 11/30/2001 00:53:33
Some of the BIOS fopr these MP systems have been konowd to be dire....

With (multiple) ioapic systems the BIOS has to assign some IRQ to the ISA
bus and others to the PCI bus - the IRQ routing is entirely different
for the two cases.

It is not impossible that the bios allocates IRQ to isa pnp that are also
allocoted to PCI cards!

With EISA/PCI/ISA pnp systems the scope for BIOS errors is exceptional!
(We had one BIOS that failed to allocate an IRQ to an EISA card because
it had already given it to someone else!)

Was also fun persuading people that we had hardware interrupting on IRQ>15
on 'PC' type systems...


----- Original Message ----- 
From: Noud de Brouwer <>
To: <>
Sent: Thursday, November 29, 2001 8:23 PM
Subject: Re: 3Com ep0

> On 29-Nov-2001 Christos Zoulas wrote:
> >did you turn on MP interrupt mappings in the bios?
> how's that done?
> bp6 can assign irq's to pci-slots not isa,
> this 3C509B is a pnpisa.
> bp6 can assign irq's to 'Legacy ISA',
> still GENERIC.MP assigns it to the 3C509B.
> bp6's bios can set 'MPS Version Control for OS:'
> to v 1.1 or 1.4, sounds not relevant to irq behaviour.
> did i overlook something in bios christos?
> ~n
> -- 
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