Still IRQ routing problems with bridged devices.

Bernd Walter ticso at
Mon Jan 5 15:16:09 PST 2004

On Mon, Jan 05, 2004 at 05:29:40PM -0500, John Baldwin wrote:
> On 02-Jan-2004 Bernd Walter wrote:
> > in use for a ISA device by an PnP On-Board component.
> Yes, our current algorithm for choosing which interrupt to use if we
> don't see one set by the BIOS already is incredibly dumb, which is
> what I said earlier. :)
> > And I don't see the point why this is not a problem for non bridged
> > devices, which would also require an IRQ for 0.2.0 INTA.

OK - now I got it.
Nevertheless the current situation is a regression to previous
behavour in such a case.
The board works fine if interrupts are left untouched.
The point is that it shouldn't take an IRQ for PCI which is configured
for an ISA device in device.hints.
I don't know the IRQ selection code and how hard it would be to fix.

> If the BIOS has already set an IRQ, we use what the BIOS says.

Mmm - this sentence makes be wonder.
The BIOS has setup everything in a working condition.
All 4 links are configured with IRQs by the BIOS.
It seems that exectly this check failed.

> If the BIOS has already set an IRQ for another device using the
> same link, we use that same IRQ.  The problem case is when the
> BIOS has not set a device yet for another device with the same
> link.  Then the "dumb algorithm" kicks in.

B.Walter                   BWCT      
ticso at                                  info at

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