Comment 27 for bug 1644919

Hi Andrew,

You need to boot to 4.4.0-XX kernel instead of mainline kernel.

The latest mainline kernel is for testing only - you can safely remove those kernels after testing is done.

To remove mainline kernels, you can run something like this:
$ sudo apt purge $(dpkg -l | grep 041100rc2 | awk '{print $2}')

Do the same for other mainline kernels you installed for testing.