"Hang" on boot

[David N Hicks <dave@prescoinc.com>]

Dear all,

I have aproblem with a PCI plug-in card I designed in '96 that has an bridge
chip and three "local" PCI devices (on the embedded bus) and I was wondering
if anyone could provide some insight.

Background:
The card was designed for a custom application (low volume, installed by
OEM) and uses the embedded chips default vendor and device IDs.  The card
does not support subsystem vendor IDs.  The three embedded devices attached
to the "PCI to PCI Bridge" are a "Bridge Device", a "Memory Adapter", and a
"SCSI Bus Device".  These devices are assigned to Device IDs 4, 5, and 6
(respectively).  Each of the three embedded PCI devices uses 1 interrupt
which is assigned to INTA for the device.  The interrupts from the secondary
bus are routed to INTA, INTB, and INTC on the primary bus PCI connector.

Problem:
The card is not working when installed in "modern" motherboards.  It doesn't
"crash" the system, but keyboards and network interfaces stop working.
Testing to date is minimal, but the problem seems like it may be an
interrupt assignment issue.  In a failing system, the Memory Adapter is
assigned the same interrupt as a network card and a USB device (Interrupt
Line B).

Any insights or recommendations on where I can look for answers?

Thanks,
Dave Hicks