msk(4) cannot receive packets on Marvell Yukon 88E8057

I just got a new laptop that has a Marvell Yukon 88E8057 ethernet
adapter.  The msk driver attaches to the hardware on the 8.1 release
candidate, and I seem to be able to transmit packets just fine, but I
can't receive packets reliably.  The first time I tried the driver a
couple of pings succeeded, but dhcp didn't and now that I've tested
for a while longer, it seems that the first ping succeeding was pure
luck.

Does anybody have ideas on where to start debugging this?  I'm willing
to test patches, gather more information and basically do whatever it
takes to get this working, as the laptop isn't too useful to me
without networking.