[Server-devel] Exploding wireless interfaces on your laptop

[Martin Langhoff]

I spent a good part of yesterday trying to diagnose why an active
antenna was failing to work on my test mauhine. Not only it was
failing, over time stranger and stranger messages would appear in
dmesg, random strings, chunks of hex. The machine would get less and
less stable, things would fail strangely. Ghosts.

For a while I thought it was an incompatibility between the newer
kernels from Fedora updates and the Libertas firmware. The Libertas
driver devs have warned me about this risk.  Or perhaps the AA
hardware was fried (the lights didn't blink correctly...). Cosmic rays
couldn't be discounted either.

It was, however, something a lot more mundane.

This test machine is a laptop, and sports its own wifi gear
(centrino). Our device naming scheme for the pair of devices that the
Libertas appears as is wlanN/mshN. However, the built-in card took
over wlan0 and so the AA was wlan1/msh0. And some things would still
talk to wlan0 as if it were a libertas.

The trivial local workaround: blacklist the iwlagn driver so the
machine forgets about it's internal card. For 0.6 we'll have to rename
the wlanN side of the libertas to get it out of the way. Some
conventional laptops do make good candidates for XS kit.

back on ejabberd then,



martin
-- 
 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
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