[OpenBIOS] PCI setup code

Marcus Gossner mgossner at inova-computers.de
Wed Mar 29 10:58:57 CEST 2000

Ronald G. Minnich wrote:
>> What problems exactly are you having in PCI setup?  I've been messing
>> around in that area lately and can help...
>first, in 2.2.10, it doesn't do ANY configuration of memory-addressable
>BARs. Second, it doesn't do any IRQ assignment. If 2.3 fixes this then
>I'll just cut over.

The IRQ assignment can't be done in the operating system. It depends on the
wireing on your board and therefore it is done in BIOS. You can check the
IRQ assignment with your original BIOS:

1. Select fixed ISA IRQs for PCI IRQs
   e.g.  PCI INTA = IRQ  9
         PCI INTB = IRQ 10
         PCI INTC = IRQ 11
         PCI INTD = IRQ 12
2. Put PCI cards in all slots
3. Boot something and look into PCI configuration space
   If for example the card in PCI Slot 1 got IRQ 11 you know now this Slot
uses PCI INTC.

Please remember to set up your chipset correctly to select with PCI IRQ use
with ISA IRQ. Then you can assign this IRQs to your PCI Slots.


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