Well, I still have the issue and haven't been able to find a fix. Updating
to the latest linux-libre kernel didn't help, and neither did all the
wireless module tricks and tricks found on Ubuntu forums.
Actually, I have found several messages on the Ubuntu forums describing the
exact same problem: a wireless connection that was rock-solid before 12.04
becomes unstable with 12.04, mostly when tranferring large files either
through samba or rsync. Unfortunately, those messages either have no answers
at all, or useless answers. It may be a combination of 12.04 and routers
with dd-wrt which causes the problem, but I couldn't find any solution after
playing around with dd-wrt's configuration.
I guess I'll just try to use a wired connection from now on, if I can manage
to pass a cable from my basement where the router is, to the ground floor
room where the desktop is.
