PCN0 problem

[T <bobs%thelibertytree.org@localhost>]

Hello,
I have a problem with the pcn0 NIC on the following machine:
https://dmesgd.nycbug.org/index.cgi?do=view&id=6120
The integrated pcn0 causes the machine to become unresponsive if 
interacting with it through NetBSD. Two specific examples I can think of 
are:
1) When I originally obtained the system, I used the firmware net boot 
functionality to load the sysinst image over the network and tried to 
install packages from a NFS share. This would initiate and load into 
sysinst, but then the system would become completely unresponsive during 
the unpacking phase of the install, as in the screen would become frozen 
on output related to unpacking the sets. Pressing the NUM_lock key would 
not toggle the keyboard LED for it and no user interaction seemed to work 
(remote ping, SSH, keyboard, debugger key sequence). I started using 
NetBSD with this machine with one of the later version 7 releases, from 
which this example originates.

2) Currently, with 9.2_STABLE, I can reproduce this problem by just 
calling 'dhcpcd pcn0', which will cause the same unresponsive behavior as 
mentioned above. I have worked around this issue by using an alternative 
add-on NIC, but interacting with the integrated pcn NIC has always been 
an issue since the original example.

The system firmware does not seem to have any problems with the NIC when 
using built-in device tests or net boot functionality.

I was wondering if anyone else has had issues with this driver (likely 
being used on a different port) and if the problem is likely not a driver 
issue, but specific to port-prep? It has been mentioned to me on IRC that 
I might need to use something like KGDB to troubleshoot the issue, but 
that would need to be added to the port, because it does not currently 
exist.