Re: linux-kernel-digest V1 #824

David A Rusling (
Mon, 07 Apr 1997 08:54:12 +0000

> My questions on your proposal are:
> > Get a list of all available PCI IRQ's, assign the first one
> How to differentiate between ISA and PCI interrupts?

Please don't. It's very hard without understanding the interrupt routing
details of the board. It is easier to let the PCI BIOS handle this.

> > The pci_set_*_irq call should be called in all drivers, just
> > before the call of pcibios_read_config_byte() for the irq.
> How will you figure out the mapping from the INT lines to the interrupt
> controller IC inputs?

Again, the PCI BIOS knows this and the PCI BIOS is specific to the boards.
Alpha, because it has no PCI BIOS, has to have interrupt routing tables, one
per supported system and do PCI fixups (in arch/alpha/kernel/bios32.c). This
would be unsupportable for Intel based systems, it's bad enough having a dozen
Alpha systems around...

David A Rusling Principal Engineer
European Semiconductor Applications Digital Equipment Co Ltd.,
Engineering PO Box 121,
Imperial Way,
Worton Grange
Reading RG2 0TU
Linux, Alpha, StrongArm, PCI Tel: UK-(0)1734-204380
Fax: UK-(0)1734-203133