Woo, I done science, me! I THINK I've solved it, and this should work irrespective of driver version. So, here's what I've discovered:
- If both DisplayPort and HDMI connectors are connected to the graphics card at the same time, the sound stream will not be routed through the HDMI port.
- Disconnecting the DisplayPort cable from the GPU, dusting off the DVI cable, 'AMD HDMI Output' reappeared on my list of playback devices, and could be set up as before.
Summary: HDMI Sound output is only possible when only DVI and/or HDMI connectors are used. If a DisplayPort cable is connected, the GPU will prioritise it for both video and audio output, bypassing the HDMI port altogether.
I haven't tested this at this time (because FIRE EMBLEM RADIANT DAWN!!!1! - I'm playing it on a Wii U, which lays claim to my receiver), but I'm 95 % confident of having found a working solution. If anyone reads this (AMD representative, plz?), I'd appreciate it to have this verified by someone else.
(Oh, and if you get the bit of in-joke I'll be very much impressed.)
hrmmm in my case my HDMI goes from my Vizio TV, which I use as a monitor, which has speakers built in. The HDMI cable goes to my HDMI port on my HD 7900. It worked fine until this upgrade. I have no other devise plugged into my graphs card..I don't get it..