xl1: watchdog timeout on 6-STABLE with 3c575B cardbus NIC

[spil oss]

Since upgrading to 6-STABLE I get errors on my cardbus NIC. If I have
the patience to wait for echo on an ssh terminal one could say that it
works, but in a real world it's unusable.

Hopefully helpful details:
* Worked fine on 5.4
* Whilst downloading a freebsd iso over ftp, no watchdog timeouts
occured and speed was 100%, but immediately after the download
finished they started popping up again (connecting seems to be slow
though)
* Inbound connections on xl1 are extremely laggy, switching screens via ssh take
a long while to start but then suddenly the whole screen is redrawn.
* My xl0 is fine (3Com 3c905C-TX Fast Etherlink XL) ssh, smb, all
works as expected.
* booting no-acpi results in the same error

snippet from dmesg:
cardbus0: Resource not specified in CIS: id=14, size=80
cardbus0: Resource not specified in CIS: id=18, size=80
xl1: <3Com 3c575B Fast Etherlink XL> port 0x1000-0x107f mem
0x88000000-0x8800007f,0x88000080-0x8800
00ff irq 10 at device 0.0 on cardbus0
miibus1: <MII bus> on xl1
tdkphy0: <TDK 78Q2120 media interface> on miibus1
tdkphy0: 10baseT, 100baseTX, auto
xl1: Ethernet address: 00:00:86:57:76:22
<cut>cut
xl1: watchdog timeout
xl1: watchdog timeout
xl1: watchdog timeout

Anyone got a clue what happens here and how I can fix this?

Spil.