wierd lockups on KNE100TX (DEC DC21142 (rev 65))

[scottk@plover.atdesk.com]

We have a 3com SuperStack II Switch 3900-36 that seems to reboot
spontaneously.  Whenever it does, it takes down networking on all the
machines on it that have DEC DC21142 (rev 65).  when this happens, these
machines are no longer able to transfer any data. The card is basically
locked up.  I have tried stopping and restarting networking, removing and
re-installing the driver, even warm rebooting fails. The only way to make
these cards work again, is to power cycle them to allow the hardware to
reset.  I ran Becker's tulip-diag tool against these cards while they were
locked up and it thought that they were working..

There are other machines on the same switch with DEC DC21140 (rev 34)
(tulip.c:v0.88) that do not lock up.  

We have 3 machines showing this lock-up behavior, all are Kingston
KNE100TX's.
They are all using tulip.c:v0.91e 5/27/99.  

Here is part of dmesg from one of the offending machines:

m16 kernel: tulip.c:v0.91e 5/27/99 becker@cesdis.gsfc.nasa.gov 
m16 kernel: eth0: Digital DS21143 Tulip rev 65
at 0x1000,00:C0:F0:3B:B7:15, IRQ 5. 
m16 kernel: eth0:  EEPROM default media type Autosense. 
m16 kernel: eth0:  Index #0 - Media MII (#11) described by a 21142 MII
PHY (3) block. 
m16 kernel: eth0:  MII transceiver #1 config 3000 status 7829 advertising
01e1.

Any suggestions other than replace the NICS and/or the switch?
Anyone?