I seem to have two devices, but not two cards:

root:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC270 Analog [ALC270 Analog]
Subdevices: 0/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0

I was able to get some sound out of hdmi by selecting the 'hdmi' device for a test sound, but can't figure out how to set that as the device that alsamixer (and anything else) uses by default. I've seen some examples where there are two cards (0 and 1) but none like the above.

Any ideas?

thanks,
Biff.

Try the following ~/.asoundrc:

What works for me is Of course, this is not a solution if you are trying to send all system sound there, but it's perfect for occasional movie-watching

As qweasd said you need to chose the hdmi as audio output in the application.
I change to hdmi in the settings in smplayer or vlc for it to work.
You should see your card in alsamixer by pressing F6 and chose your card.
But i got card 0 and 1 so it might differ.

Indeed, that works on another machine, with on-board audio and HDMI on the graphics card, but I think in the case above I have one chip, with two outputs (laptop with Intel chipset).

What kernel do you have?

I had similar problem with my machine and it went away after a kernel update to --Current (this is a machine that serves mainly as a file server, so I decided to wait it out).

I had tried all the tricks here, but it was the kernel update that did it. It's currently at v. 4.1.6.

I think this should be

2 members found this post helpful.

That fixed it! The only caveat is that after that alsamixer doesn't seem to be able to control the volume any more, however I can control it on the TV or in Firefox, so good enough for me!

Does it only show IEC958 as a control (uncontrollable) in alsamixer on HDMI? Because that's all it should show as far as I know. You just use master volume to control the volume.

try adding
defaults.ctl.device 3

may or may not do it