Comment # 6 on bug 104391 from Andy Furniss

It seems that

HDMI has no sound after Panel power off/on

is the cause of the warnings.

I tested 4.18-wip, no sound of course but nothing in dmesg.

I then applied "HDMI has no sound after Panel power off/on" as a patch and get
no sound + the warnings in dmesg on enabling the TV.

Remove the patch, then 

git revert cfb071f7a9673109415d097125b3c12c16836acc 

= working sound.