Forcing 8259A for one irq.

Zwane Mwaikambo (zwane@linux.realnet.co.sz)
Fri, 2 Nov 2001 09:44:35 +0200 (SAST)

I've got a strange scenario whereupon i have a box with IO-APIC enabled
(SMP box) and a driver which seems not to be SMP safe and only works if i
boot the kernel with noapic. My question is, which is the cleanest way of
making a specific IRQ use the 8259 instead of IOAPIC? (kind of like the
timer on some boxes).

I've looked at the enable_8259A_irq function, but my method looks terribly
incorrect (and untested too). Would this method work? And is there
anything i should look out for?

irq_num = IRQ below 15 (specified as parameter to module)
add entry to IO-APIC routing table? (local-apic to CPU#0)
enable_8259A_irq(irq_num)

This is only a temporary measure until i get the driver completely SMP
safe and i want to avoid running noapic.

Thanks in advance,
Zwane Mwaikambo

--
Anyone for a LUG in Swaziland?


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