siop0: couldn't map interrupt

Hi,

experimenting with Open Firmware for QEMU PReP target.
Since QEMU doesn't support Plug'n'Play extensions for ISA, I thought
I'd better use a PCI card.
NetBSD sees it but

siop0 at pci0 dev 4 function 0: Symbios Logic 53c895a (ultra2-wide scsi)
siop0: using on-board RAM
siop0: couldn't map interrupt

How does NetBSD/prep map interrupts? Does it use residual data?

-- 
Regards,
Artyom Tarasenko

SPARC and PPC PReP under qemu blog: http://tyom.blogspot.com/search/label/qemu