Comment 2 for bug 442644

Few more notes:

Watching from the commandline this time; ifconfig showed the network interface up throughout, no errors reported.

Ping times were pretty bad - 90-120ms to another machine on the local network. Once fixed this was more like 1-5ms. Occasionally much longer pauses.

Then:

64 bytes from mab.local (192.168.0.163): icmp_seq=171 ttl=64 time=89.3 ms
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
ping: sendmsg: No buffer space available
^C
--- mab.local ping statistics ---
199 packets transmitted, 158 received, 20% packet loss, time 230681ms
rtt min/avg/max/mdev = 1.150/75.710/1018.121/97.880 ms, pipe 2

Restarting the ping seemed to make it work again for a bit, but as before, actually putting more traffic through (ie: browsing a couple of pages) made it fall over completely.

So then, instead of rebooting as previously, I did the following:

Disable wireless networking in network manager
rmmod ath9k
rmmod ath
rmmod mac80211
rmmod cfg80211
modprobe ath9k
Re-enable wireless networking in network manager

Network reconnected, and has been fine ever since.