Situation: Audio is not working over HDMI
Possibility 1: The TV/Monitor is not being detected in CEA mode
DMT is only well defined in DVI and DVI can not do audio. Audio only works in CEA modes..
# run to detect if tv/monitor mode tvservice -s # tvservice -m CEA # tvservice -m DMT
Uncomment the following in
/boot/config.txt to force an HDMI mode. It can make audio work in DMT (computer monitor) modes.
/boot/config.txt is kinda like the Linux version of BIOS settings
# Force the monitor to HDMI mode so that sound will be sent over HDMI cable hdmi_drive=2
Now reboot for the changes to take effect