I have Radeon card connected over HDMI to my TV. To resolve bug with HDMI-sound, I switch between virtual terminal and GNOME desktop each time the TV is switched on with CTRL+ALT+F1 and after console appear with CTRL+ALT+F7. It's ugly, but its worked for me. Since yesterday I got system freezes on CTRL+ALT+F1 - no reaction on keyboard, mouse pointer disappear at all, GNOME desktop still displayed. Probably has nothing to do with HDMI. Any suggestion how to resolve it?