Workaround script to help solve Ubuntu 16.04 HDMI sound issues when ALSA can use the HDMI sink, but Pulse thinks it's unplugged

fix_sound.sh

#!/bin/bash
{
	#
	# Get rid of pulse and its cache (so this script can be run multiple times)
	#
	rm ~/.config/pulse/*
	pulseaudio -k
  
	#
	# Wait till pulse sorts itself out
	#
	sleep 2
  
	#
	# Find the HDMI "cards" - you will likely have to modify this grep since it is atuned to my 
	# NVidia graphics card's active HDMI audio output device
	#
	card=$(aplay -l | grep "NVidia.*HDMI 1" -m 1)
  
	#
	# Log the card 
	#
	echo $card
	if [ "${card}" ]; then
		#
		# We have a card, so now we parse the aplay output line
		#
		# Effectively, it you split it into an array by "," and ":" then:
		#
		#    the card number is the last "word" of the first item in the array
		#    the device number is the last "word" of the third item in the array
		#
		IFS=',:' read -r -a details <<< "${card}"
		card_number="${details[0]##* }"
		dev_number="${details[2]##* }"
    
		#
		# After that, just force-add the device's associated ALSA sink to Pulse
		#
		pacmd load-module module-alsa-sink device=hw:${card_number},${dev_number}
		#
		# And force Pulse to use that ALSA sink as the default output
		#
		pacmd set-default-sink alsa_output.hw_${card_number}_${dev_number}
	else
		#
		# Can't find your card - fix the grep on line 18?
		#
		echo "No HDMI sound target found"
		exit 1
	fi
#
# And we put all output into a log file in the home directory
#
} >> ~/fix_sound.log 2>&1

Finally! After days digging the web for a solution, yours is the only one that really worked. Thanks a lot!

Finally, I helped someone - in the words of my wife "That almost NEVER happens"!