Nvidia drivers don't work with mainline kernel

Solution 1:

(answering my own question, as Bruno suggested in comments)

This problem is fixed by installing the Nvidia-provided drivers by hand, following the below steps.

1. Download the drivers from the Nvidia website
2. Reboot into recovery mode as the drivers won't install with X running. Do this by rebooting, holding shift if necessary to get into Grub and choosing the recovery option, then "Root shell" at the text menu.

3. You should now be faced with a shell that looks something like this:

   root@sirius:~# 
   

   Enter the following command so that the root filesystem is writable:

   mount -o rw,remount /
   

4. Install a few required packages (you may need to do dhclient eth0 to bring the network up beforehand):

   apt-get install dkms
   

5. Make the Nvidia installer executable and run it:

   chmod +x $INSTALLER_FILE
   ./$INSTALLER_FILE
   

   where $INSTALLER_FILE is the location where the installer is downloaded to (use tab-completion to help you, probably something like /home/josh/Downloads/NVIDIA-Linux-x86_64-302.17.run)

6. Work through the steps in the installer. The defaults should work.

7. Reboot into a normal system.