This what I had to do to get sound out through HDMI put from an Ubuntu 16.10 system on Intel NUC6CAYH. I hope it helps the dev's
Its very, VERY flakey. Breathe on it & sound stops working again. Totem kills the sound reliably so uninstall it & use VLC.
Note 1 : The package 'oem-audio-hda-daily-dkms' does not exist in the Graphics drivers PPA.
Note 2 : Ubuntu 16.10 is the most recent being packaged for by the ALSA PPA guys.
Note 3 : Keep your resolution no higher than 1920x1080 or no sound via HDMI again..
Note 4 : When sound via inevitably stops, Log out & back in. Check sound mixer settings & return them to HDMI/Display port/Stereo etc again.
Follow these steps to resolve the issue:
1. Make sure that your system is up-to-date using the Update Manager.
In a Terminal window, run the following:
sudo apt-get update && sudo apt-get upgrade
Reboot the system.
2. Add the following groups to your account:
audio, pulse, pulse-access, video, voice
( Install the better user/groups gui to manage this:
sudo apt-get install gnome-system-tools )
3. Add the Graphics Drivers PPA
[ Oibaf : Updated and Optimized Open Graphics Drivers repo ]
[ Updated and Optimized Open Graphics Drivers : Oibaf ]
In a Terminal window, run the following:
sudo add-apt-repository ppa:oibaf/graphics-drivers
sudo apt-get update
Reboot the system.
4. Add the ALSA PPA (all versions of Ubuntu up to 16.10, 17.04 NOT supported)
[ ALSA daily build snapshots repo ]
[ ALSA daily build snapshots : “Ubuntu Audio Development Team” team ]
In a Terminal window, run the following:
sudo add-apt-repository ppa:ubuntu-audio-dev/alsa-daily
sudo apt-get update && sudo apt-get install oem-audio-hda-daily-dkms
Reboot the system.
5. Make this directory if it does not exist under /etc/X11:
sudo mkdir xorg.conf.d
Create this new file:
sudo nano /etc/X11/xorg.conf.d/20-intel.conf
Paste this content into the newly created file:
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
# Option "SwapbuffersWait" "true"
Option "AccelMethod" "SNA"
# Option "AccelMethod" "UXA"
Option "TearFree" "true"
Option "DRI" "3"
EndSection
To revert to standard Ubuntu graphics drivers type the following in a prompt shell:
$ sudo apt-get install ppa-purge
$ sudo ppa-purge ppa:oibaf/graphics-drivers
To revert to standard Ubuntu ALSA drivers type the following in a prompt shell:
$ sudo apt-get install ppa-purge
$ sudo ppa-purge ppa:ubuntu-audio-dev
