USB/NE2000 IRQ conflict?

Gary Aitken freebsd at
Tue Jun 17 11:24:22 PDT 2003

In my case, I have one Netgear card which I can manually configure, 
and one generic card which I cannot, plus an SMC Etherpower (dec 21041 
chip) card which also cannot be configured (the mfg configuration 
program only allows configuration of the media type).  By manually 
configuring the Netgear card, I can get the other ne2000 card to use 
irq 5, so I can get those two working.  But the smc card always comes 
up at 9, and the video card comes up at 15.  The video card works in 
this system, but the smc card doesn't.  If I swap the smc card and the 
video card to another system, they come up reversed (smc card at 15, 
video card at 9) and both work fine.  I've tried moving the cards 
around in the slots, but can't get the irqs to shift.  Nothing is 
landing on irq 12, so I don't think that is a problem.
I was hoping that putting them in the system where they work would set 
the irqs, and those irqs would be honored when moved to another system 
in the absence of a conflict.  But that doesn't seem to be the case.  
I put both cards in the system where they work, then put them in the 
system where they don't, and booted dos and ran the mfg config utility.  
It showed the smc card back at 9, rather than at 15 where it was in the 
previous system.
Can someone give a brief explanation of what the difference is between 
a plug and play setting and one that is manually set?  Is there no way 
to give FreeBSD hints as to where you would like P&P cards to be placed?
Adam Maas wrote:

The ne2000 nic has setup utility that you run from ms/dos that you
can set the nic's irq with. If you did not get one in the box the
Nic came in them check out the MFG website.

That is not the case for RTL8029 based NIC's, which are PCI NIC's that
emulate the NE2000 for driver compatibility. They are assigned IRQ's like
any other PCI card, rather than using a setup utility like the real NE2000
ISA cards.

That said, have you tried a different slot? IRQ12 is often problematic,
since it's supposed to be reserved for PS2 Mice on most systems. See if your
BIOS allows you to exclude that IRQ somehow.

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