wm devices don't work under current amd64

[Tom Ivar Helbekkmo <tih%hamartun.priv.no@localhost>]

I've recently set up a Dell E6400 laptop with NetBSD, and it's working
great - over WiFi.  The built-in wm ethernet interface doesn't work.  It
can send packets out, but can't receive anything.  I tried booting Linux
on the laptop, and it has no trouble with it.  Here's the device:

wm0 at pci0 dev 25 function 0: 82801I mobile (AMT) LAN Controller (rev. 0x03)
wm0: interrupting at msi0 vec 0
wm0: PCI-Express bus
wm0: 2048 words FLASH
wm0: Ethernet address 00:26:b9:cd:21:c2
makphy0 at wm0 phy 2: Marvell 88E1149 Gigabit PHY, rev. 1
makphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 1000baseT-FDX, auto

I first tried installing from a CD containing the NetBSD/amd64 install
image from October 10th (7.99.21).  After that failed to work for the wm
device, I built a new image, using a current from March 4th (7.99.26).
That also failed to work, but it doesn't get kernel panics relating to
arp on the WiFi, so the laptop is working nicely enough without wm0.

However, since I'd built a newer current anyway, I tried upgrading
another Dell box, a 2650 that I use as a server.  It also has wm type
networking devices, which work just fine with 7.99.21.  Surprisingly,
upgrading to 7.99.26 broke them.  The hardware is different, of course:

wm0 at pci6 dev 7 function 0: Intel i82541GI 1000BASE-T Ethernet
(rev. 0x05)
wm0: interrupting at ioapic2 pin 0
wm0: 32-bit 66MHz PCI bus
wm0: 512 words (16 address bits) SPI EEPROM
wm0: Ethernet address 00:13:72:f7:00:06
igphy0 at wm0 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 1000baseT-FDX, auto

I also use this wm0 differently from the plain use I've attempted with
the laptop: this server runs 802.1q VLAN trunking on wm0, and acts as a
router (with pf firewall) between a number of VLANs.  The failures of
the wm devices on the two machines may thus have different causes,
related to either the different hardware, or the difference in use.

Grateful for any hints, things to try, etc.  :)

-tih
-- 
Elections cannot be allowed to change anything.  --Dr. Wolfgang Schäuble