Bad auto-negotiate on network adapter ...

For some reason, my 10/100 Mbps Ethernet adapter has "auto- negotiated" to 100 HALF, which is causing lots of problems.

$ lsattr -El ent0 | grep media_speed
media_speed Auto_Negotiation Media Speed True


$ entstat -d ent0 | egrep 'Errors|Speed'
Transmit Errors: 2345374 Receive Errors: 0
No Carrier Sense: 14 CRC Errors: 0
Lost CTS Errors: 0 Alignment Errors: 0
Max Collision Errors: 79 No Resource Errors: 0
Late Collision Errors: 2344978 Receive Collision Errors: 0
Deferred: 393260 Packet Too Short Errors: 0
SQE Test: 1 Packet Too Long Errors: 0
Timeout Errors: 0 Packets Discarded by Adapter: 0
No mbuf Errors: 0
Media Speed Selected: Auto negotiation
Media Speed Running: 100 Mbps Half Duplex
No Receive Pool Buffer Errors: 41664

The switch side is set to auto; this hasn't been a problem for my other systems (AIX and Solaris.)

Can I force the card to re-negotiate by doing an ...

ifconfig en0 down ; ifconfig en0 up

... or is there something else I can do to get it to re-negotiate (short of rebooting)?

Thanks,
-s-