Re: hdmi out not working to external monitor
You're right, it's not a hardware issue -- it's an issue of the version of the video driver being incompatible with the version of the kernel.
If you're using open-source drivers, you should not be having this problem.
If you're using restricted drivers, and you installed them from a website -- you will continue to have this problem because you have to "remake" the drivers for every kernel update.
If you, instead, install the restricted drivers through Additional Drivers, that installs them differently, such that, when you update the kernel, the drivers get updated automatically.
I don't use Additional Drivers myself, so I don't have the commands handy.
Ubuntu 16.10 Mate, Mint 18 Mate; MS Win 8.1, MS Win10 Pro.
Will not respond to PM requests for support -- use the forums.