I had a few problems getting my HDMI sound working on my ASUS S1-AT5NM10E that I bought recently.
The problem seemed to be based around the sub-device being used by HDMI was not the default and the easiest way to get it working with LMCE was to use a probe-mask so that effectively I only had one sound device on the system.
Can you get sound doing
speaker-test c2 -D plughw:0,7
aplay -Dplughw:0,7 <some audio file>
With any of the devices? (ie: substitute the 7 for 3,8,9)
Enter the result of aplay -l and aplay -L
If you can get sound to work explicitly as above then you will be able to use a similar solution to mine.
ps: disable you onboard sound in the BIOS as well.
after more discussion in irc with uplink, possy and tschak, i pretty much determined that im boned. Alsa is an inconsistent pos from version to version. Simple as that. Long story short as it was explained to me, different alsa versions need to be installed for different sound cards / devices. ALC887 (my onboard) works 'ok' with with the install i was trying to get away from with its failing disk. However, same drivers dont work on the same hardware on a new install. go figure.
We thought the diff was that alsa was at 1.0.18 and thats why my onboard was having issues. Turns out, thats the same version on my functional install. I am completely confused @ this point. I wish i could say there was a way to check what was compatible, but if that is changing all the time its a crapshoot and ive got no idea how to solve it.
I did try speakertest to the point of seeing it outputting information in the console, but no sound. Over the past few days ive been through a hundred or so alsa related pages and nothing seems to work. So i guess im just stuck with this install until it dies then ??