Re: [PATCH] MSI interrupts: disallow when no LAPIC/IOAPIC support

[Grant Grundler]

On Tue, Sep 27, 2005 at 11:37:50PM +0100, Alan Cox wrote:
> On Maw, 2005-09-27 at 17:26 -0400, Jeff Garzik wrote:
> > Grant Grundler wrote:
> > > I've no clue why folks thought it was better to ignore
> > > the IO APIC on UP kernels.
> > 
> > Hysterical raisins:  the -majority- of the early uniprocessor systems 
> > that claimed IOAPIC support were broken.
> 
> Not really broken in most cases, but since nobody was using the APIC
> board makers didn't bother wiring for it.

ok. Any clue how PCI IRQs got routed/handled on those boxes?
Did UP boards have an 8259 PIC and an IRQ line to the CPU?
Could an 8529 PIC even co-exist with an IO APIC?

Or was it something more silly like BIOS mfgs had no version
of Windows that could grok a IRQ routing table and thus no
incentive to enable that feature?

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