Can you actually use that DVI>HDMI dongle on the back of your video card in Linux? Why yes, you can, & the Phoronix guys lay it all out for you so that you'll wonder why you ever questioned it in teh first place.

"But what level of HDMI support can Linux users expect when using these latest ATI graphics cards? We have done some testing internally and have the initial ATI Linux HDMI video and audio results to report in this article."