bge problems (bcm5752 broken?)

I'm having troubles getting the BCM5752 ethernet
controller in my new HP DC7600 to work with either
-CURRENT or 6-STABLE.

Running dhclient on bge0 seems to generate no output
packets (according to tcpdump on another machine)
and dhclient eventually gives up.  I've also seen
occasional messages about "firmware timeouts."

Any debugging suggestions welcome.  (I've not spent
much time looking at Ethernet drivers, so I'm
not really sure where I should start.)

Tim Kientzle