[COLUG] Invalid MAC address on new HP F750US laptop

[charles morrison]

February 25, 2008

I recently purchased a laptop, HP model F750US, and found after 
installing Kubuntu 7.10, that the MAC address was invalid. A message 
occurs in dmesg output advising I complain to the hardware vendor. I 
thought this was strange and thought perhaps this was due to a security 
type change to laptop design or something. The laptop works pretty well. 
While connecting it to my network and attempting to disconnect it from 
wireless, I found that my network configuration changes were not 
persistent and after some searching, found the following:

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Flakey BIOS in Gigabyte GA-M68SM-S2L Makes MAC Address Change on Reboot
Over the weekend I have been setting my new Mythbuntu pair, a split. 
back end and front end. Everything has gone pretty smoothly.
One issue I did hit was the onboard NIC on my Gigabyte GA-M68SM-S2L 
motherboard despite what the specs say it is a "nVidia Corporation 
Unknown device 054c (rev a2)" which uses the forcedeth driver. Everytime 
I rebooted the box the NIC would increment its interface number - eth0, 
eth1 ... eth6 and so on. Changing the "Smart LAN" setting in the BIOS 
from auto to disabled just disables the NIC, not what I wanted.
After googling I discovered that others had experienced similar problems 
with ASUS boards with nVidia NICs, changing their MAC addresses. Looks 
like Gigabyte (and ASUS) have been shipping invalid MAC addresses on 
some of their boards, and forcedeth isn't happy about it, so it just 
generates a new (valid yet) random MAC address.
With a little help from sysfs I was able to hack my udev config so it 
all works now. My /etc/udev/rules.d/70-persistent-net.rules looks like

SUBSYSTEM=="net", DRIVERS=="forcedeth", ATTRS{vendor}=="0x10de",
➥ ATTRS{device}=="0x054c", NAME="eth0"
I grabbed the output of "cat /sys/class/net/ethX/device/{device,vendor}" 
to populate the relevant ATTRS entries above.
I am not sure what you do if you have 2 onboard NICs and they are both 
broken.
Gigabyte (and ASUS) or nVidia should look at fixing their broken kit to 
save people from wasting time on this.
by Dave at February 10, 2008 12:09 PM

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I have not attempted to implement this change. The symptoms were that my 
device number kept incrementing. IE eth0, eth1, eth2, etc each time I 
connected. This means that the system detected a new device each time 
and assigned a different device name to it with default configuration. 
This laptop does have the NVidia ethernet chipset. I also checked my 
70-persistent-net.rules udev file and found 26 different definitions in 
the file, eth0 through eth26.

When I get this working, I will post an update.

Charlie Morrison