rickb@iaw.on.ca said:
> Dec 20 18:07:24 rick /netbsd: com2 at isapnp0 port 0x3e8/8 irq 5:
> ns16550a, working fifo Dec 20 18:07:24 rick /netbsd: sb0 at isapnp0
> port 0x220/16,0x330/2,0x388/4 irq 5 drq 1,5 
> [...]
> And now there is definantly an IRQ conflict.  Neither the modem nor the
> soundcard seem to function properly.

What probably happens here is:
-the modem picks irq5 because this is the first available
 line (3 and 4 are used by com0/1)
-the sb card does only allow for irq5, or the irq5 is part
 of the first set of "dependant functions" tried
Pulse triggered IRQs are allowed to be shared in principle,
so the setting is considered OK by the kernel.

As a workaround, you could try to disable com0 or com1
in the BIOS, hoping that the modem will pick up irq3
or irq4.

I can't tell a quick solution for the code - this would
all affect the guts of the isapnp framework.

> I tried setting my bios option "PNP OS
> installed" to NO (which I thought might make the BIOS assign irqs to the
> cards), but it didn't help.

While it is generally right to switch "PNP OS" off in the
BIOS, this doesn't help here. The isapnp framework does
its own ressource management in any case and ignores what
the BIOS did to the cards.

best regards
Matthias