I'm glad to hear you found the problem!

Note that if the LAN chip does not report a valid MAC--say, if the board manufacturer didn't set one--then Linux will assign it a probabilistically unique MAC that will change on every boot. ifconfig can be used to set a fixed one, though that requires a minimal amount of work to find a per-device unique ID on which to base the MAC. My Tobi isn't plugged in or I'd check to see if Gumstix does assign MACs.

Careful with DHCP here, as it can start before the MAC is changed and produce strange DHCP traffic.

The correct way is to pay for a MAC range to put it in, but it's kinda pricey for small runs.


On Jul 15, 2013 12:45 PM, "Ross Berteig" <Ross@cheshireeng.com> wrote:
Thanks for the prompt reply, and the pointer to where it keeps its
brain. Editing /etc/udev/rules.d/70-persistent-net.rules worked.

On 7/12/2013 5:42 PM, Michael Wynne wrote:
> This is just what popped into my mind immediately as I was reading this,
> so your mileage may vary, but I am using an AirSTORM with a Pinto-TH
> board using both Bluetooth and WiFi. I am also using a custom
> OpenEmbedded image, not Linaro. Though both are Debian-based.
> I have about a dozen of these that I'm working with right now and I've
> noticed that udev will assign a different device name to the wlan device
> based on the MAC address. So the image is configured to bring up wlan0,
> but udev has assigned it wlan1, for example. Every time I put the
> microSD in another COM and boot it adds another entry into
> /etc/udev/rules.d/70-persistent-net.rules based on the wlan MAC and
> increments the wlan device name.

I am running Linaro 12.11, which is Ubuntu and hence also Debian. I
found the file /etc/udev/rules.d/70-persistent-net.rules and in it were
rule stanzas for each of the three boards (two Tobi and the Chestnut43)
where that particular AirSTORM got mounted while I flailed at the
problem, each showing a distinct name for the interface. To save myself
trouble in case I swap the card around again, I left all present, but
changed them all to name it "eth0". I figure it can only have one
carrier board mounted at a time. For completeness I should probably
tease the MAC address of my third Tobi out of it and add that one too...

I guess the new user experience whine I should post upstream is that the
boot sequence called the interface "eth0" early on, then rather than
noticing that it had a different MAC addr than last time and saying
something in the boot log, it just silently gave it a new name.
Ross Berteig                               Ross@CheshireEng.com
Cheshire Engineering Corp.           http://www.CheshireEng.com/

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