Comment 26 for bug 540827

I got trouble with this chipset too. I also needed to unplug/plug it frequently and tha was annoying.
I fixed the trouble by using compat-wireless:
- download Stable compat-wireless from http://wireless.kernel.org/en/users/Download/stable/ and extract the content
- install linux-headers-generic package
- these commands
./scripts/driver-select ar9170
make
sudo make install
sudo make unload
modules="cfg80211 mac80211 ar9170usb"
for i in $modules; do sudo modprobe $i; done

It works like a charm scine these operations :).
I'm running Ubuntu 10.10 with linux 2.6.35 amd64