I've trolled the internets to make hdmi work on my system Ubuntu 12.04 software center kernel 3.5 uname: Linux ubuntu 3.5.0-18-generic #29~precise1-Ubuntu SMP...x86_64 x86_64 x86_64 GNU/Linux open source radeon drivers vgaswitcheroo (hybrid intel/radeon gpu): I boot with intel, not radeon, running. (and recall that with kernel 3.5, vgaswitcheroo now gives info on a third item, "DIS-Audio"; it indicates pwr on my system) ( /etc/rc.local: chown user:user /sys/kernel/debug/ # change "username" with your user name echo OFF > /sys/kernel/debug/vgaswitcheroo/switch ) grub indeed now has "radeon.audio=1"

for testing audio, I did aplay -l which gave me the card and device, which made me try aplay -D plughw:1,3 /usr/share/sounds/alsa/Front_Center.wav

and lo! I get crystal clear sound on my hdtv. If I play an mp3 file as the argument to that command, I get noise as, I guess, aplay interprets the mp3 code as a wav. If I play a .wav that is not in the /usr/share/sounds/alsa/ directory, I get nothing. Internet flash video in browser plays no sound over hdmi. Both system sounds control and pavucontrol have hdmi cedar selected. Alas, I can not get sound for any gui test (left, right).

Why would only aplay, and only when directed with "-D plughw", yield sound over hdmi? I've also tried only using one sound program at a time, if it was a limitation of alsa, so I tried aplay with web browser and even the sound control gui closed. I tried each of the last two, running alone. No improvement.

alsamixer only shows hda intel and I think it's only the intel audio, not the hdmi.