I am connecting a new ECS MB with ATI Radeon HD graphics to a Toshiba HD flat screen DMI to HDMI. Pitcture is great! However, the sound doesn't work. One time only I received a popup indicating I would need to run audio cables to the TV, because of the "HDMI to DVI connection"...except it's HDMI-HDMI...The PC just THINKS it's HDMI to DVI. I can't find any settings anywhere that would let me direct the settings to HDMI. The drivers are up to date. Ever heard of this?
Not sure if this will help you but if you right click the speaker in the bottom right corner and press playback devices you should see AMD HDMI Output. Try right clicking it and pressing Set as default device.
Thank you. That wasn't the exact answer, but it led me to the solution. The playback devices tool insisted that there was no HDMI device hooked up. So, I decided that maybe the TV, somehow was giving the wrong feedback. Playing around with the TV's settings, I found that even though the TV sound appeared to be set for HDMI, digging deeper there was a setting that had sound set as "PC". How odd. I would expec that from the VGA selection, but not HDMI. Anyway, I changed it to digital, Dolby and viola'. It began working.
The loss of HDMI audio after switching or refreshing the signal seems to be related to the ATI driver defaulting back to DVI-D mode.
It seems to be present in the 10.x through 11.x drivers. You may also get a popup incorrectly indicating that the ATI card is connected to a DVI-D monitor.
It seems that the ATI drivers now assume DVI-D by default. So if you switch the monitor after boot time BIOS initialization, the HDMI connection does not EDID handshake properly and default the output back to no audio DVI-D mode.
I wish that ATI would put a monitor EDID display and refresh buttons into CCC to make troubleshooting a bit easier.