Dell D800 (FBSD 5.2-release) Broadcom BCM5705M MTU/Jumbo Problem

[Mike Hunter]

Hi everybody,

I'm going to be trying to get gigabit throughput between my laptop (Dell
Latitude D800 running 5.2-release) and a shuttle box running FreeBSD 5.1 
(not in front of me at the moment.)  As part of the process, I attempted
to increase the frame size on my laptop, only to be greeted with
disappointment:

celeste# ifconfig bge0
bge0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
        options=1b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
        ether 00:0b:db:99:d6:06
        media: Ethernet 1000baseTX <full-duplex> (none)
        status: no carrier
celeste# ifconfig bge0 mtu 9000
ifconfig: ioctl (set mtu): Invalid argument
celeste# ifconfig bge0 mtu 1501
ifconfig: ioctl (set mtu): Invalid argument
celeste# ifconfig bge0 mtu 1500
celeste#

The C file talks about being able to do jumbo frames when the mtu is big
enough...anybody know what I'm missing?  My card is a "Broadcom BCM5705M"
and I'm running FreeBSD 5.2-release.  When I asked google, it mostly
pointed me at comments in if_bge.c talking about jumbo frames :|
 
Thanks,

Mike