I have a Sapphire HD 7970 OC in my gaming rig that is hooked to my Panasonic TC-L32U3 TV via HDMI, with a Yamaha RX-V371 AVR in the loop after the TV. The only way I've been able to get any kind of HDMI audio device showing as plugged in and usable in the Windows Sound panel is if I disable my Realtek HD Audio onboard sound, in which case my TV shows as an AMD High Definition Audio Device, but it will only configure as stereo.
The Realtek "ATI" HDMI audio driver when installed and the AMD HDMI Audio drivers that install with the graphics driver always show as "unplugged", even if all other devices are disabled.
When I try to go the reverse direction and plug the PC into the AVR first, then the TV, I always get black screen. Thus I've been sufficing with lesser quality optical audio from my PC to my AVR.
My receiver supports ARC, which I use for TV broadcasts, but I'm not sure if it supports HDMI video pass through from a PC to the AVR to the TV, or how to enable it if it does. Even if I CAN get the AVR to pass through the video from the PC to the TV though, there's still the issue of whether I can get HDMI audio from the PC.
Other than the components mentioned, I'm using a Belkin Pure 8' HDMI cable from the PC, which I'm pretty sure is v1.3. The other HDMI cable in the loop is a 6' v1.4 from Monoprice, but it's not long enough to reach from the PC to either the TV or AVR.
It appears my only option might be if I can somehow manage an HDMI video pass through from my AVR to my TV, but I need it to enable HDMI audio as well.
My receiver manual for connectivity info: http://download.yamaha.com/api/asset/file/?language=sv&site=se.yamaha.com&asset_id=23367