I know this is a common problem and I've been reading related questions, but none have helped me so far. Please help if you are able. it's been a week and still no progress on my own attempts to repair
I'm a new Ubuntu user and recently installed 12.04 on my PC tower that is only used for the TV (mainly Netflix). It's a basic Lenovo desktop (can give details if necessary) and I'm connecting it with an HDMI cord to a Sony Bravia TV that has been used for Windows OS (7 & 8) without problem. I have picture, just no sound. When I go to system settings > sound, HDMI/Display Port is an option. The only other option is Analog Output. Sound works when headphones are connected to the tower.
Note: I don't have computer monitors in my household, just the 32" bravia and a 24" (?) TV which runs off a Windows laptop. I also don't have computer speakers.
update: HDMI/Display Port is not longer an option, probably goofed something up. "dummy control" is in its place now. Analog control went away when HDMI/Display Port disappeared; again probably something I unknowingly screwed up.
this is my result from aplay-L: http://pastebin.com/w0DLTsVj
is it possible that this problem is related to my graphics card? it's what came on the Lenovo; hynix semiconductor (hyundai electronics) radeon HD 3000. as in the comments below, I installed pavucontrol, but no luck; dummy control is still my only option.