Various network issues with an Enterprise 4500

[wecc]

I've got Gentoo running on an Enterprise 4500 but with some network issues.

First, I've got two sun gem gigabit sbus cards installed, which show up in prtconf -pv as follows:
Node 0xf00f00f0
.node: f00f00f0
local-mac-address: 080020c6.0cb1
gem-rev: 00000000
burst-sizes: 0078007f
shared-pins: 'serdes'
board-rev: 00000005
interrupts: 00000004
compatible: 'SUNW,sbus-gem'
model: 'SUNW,sbus-gem'
has-fcode: ' '
version: '1.7'
device_type: 'network'
address-bits: 00000030
max-frame-size: 00004000
reg: 00000001.00100000.00000014.00000001.00200000.00009060
name: 'network'

The gem driver is compiled into the kernel, yet I get no ethernet interface for either of them. Nothing relevant to speak of in dmesg. What do I have to do to get these to show up?

The second issue, which is really the more important one, is that the HME chips on the I/O boards seem to have some kind of bug: These are the ones where the ethernet and SCSI controllers are in the same chip. The problem is, when you take the ethernet interface down, it seems to take the SCSI port with it. That can't possibly be right, can it?