Comment 58 for bug 1583801

It might be of interest that together with this "no sound in jack" problem, my screen stopped to turn off after the specified amount of time. It locks, but does not turn off. I resolved this with
xset +dpms
xset dpms 300
but the Ubuntu Settings / Brightness & Lock didn't work as regards turning off the screen.
So it might be another hint the problem is somehow related to power management

(Dell 7790 17" G7 Gaming Laptop)