I was experiencing this bug. With the upgrade to kernel 3.19.0-21-generic, the issue seemed to go away and my HDMI audio out returned. However, if the computer goes to sleep the HDMI audio disappears again. Restarting the computer is the only solution I have found to bring it back, but it again disappears if the computer suspends.
I was experiencing this bug. With the upgrade to kernel 3.19.0-21-generic, the issue seemed to go away and my HDMI audio out returned. However, if the computer goes to sleep the HDMI audio disappears again. Restarting the computer is the only solution I have found to bring it back, but it again disappears if the computer suspends.