How do I get an Atheros AR8162 working?

OK, managed to fix the problem. I downloaded and installed compat-wireless-2012-02-28-p.tar.bz2 from http://linuxwireless.org/download/compat-wireless-2.6/ .

tar -xvf compat-wireless-2012-02-28-p.tar
cd compat-wireless-2012-02-28-p
scripts/driver-select alx
make
sudo make install
sudo modprobe alx

Note: This fix will NOT work with newer versions of compat-wireless-2012-02-28-p.tar.bz2. Alx was removed from newer versions. Use the exact file described here.

Update 2012/09/05: working on Dell Inspiron 14z with same chipset using the tarball compat-wireless-2012-09-01-pc.tar.bz2

In my case (Ubuntu 12.10 with Inspiron 14z), just installing the linux-backports-modules-cw-3.6-quantal-generic package solved the problem. Here's the magic command:

sudo apt-get install linux-backports-modules-cw-3.6-quantal-generic

If you can't run apt-get on your machine (because of the lack of a network connection) you can download the package here. This link is for the 3.5.0.27 kernel - the latest in quantal. You may need a different verion of the package to match whatever you're running (see the output of uname -a).