Comment 88 for bug 767192

The results with 2.6.38-9.43 are odd. I browsed the changelog and nothing stood out as potentially causing this change on the surface. Did you boot more than once to check that it wasn't a fluke?

There was a new stable kernel this week that has some ahteros fixes. I don't think any will fix your problem, but it might be worth trying if you get a chance. It's available at

  http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.38.5-natty/

I'll start a dialog with the maintainers to see if they can provide an appropriate fix.