Is the ATI linux driver for the Sapphire ATi Radeon HD 2400 PRO 256MB PCI-E card supported for HDMI, video and audio? The article Using HDMI With ATI Radeon HD Linux Drivers, Dec 13, 2007, by Michael Larabel in Phoronix Forums said HDMI was supported on the ASUS Radeon HD 2600PRO 256MB with a DVI to HDMI dongle but alsa audio was a problem. Now that alsa v1.0.16 says its fixed this problem I'm hoping the Sapphire card is fully supported. Does anyone know?
I haven't tested it myself but it should work. The main point is that you need two things -- a video driver which enables the audio feed onto the HDMI video output, and an audio driver which understands the concept of having an audio controller on the graphics card rather than just on the motherboard.
The fglrx driver turns on the audio output; radeonhd was patched recently to do the same; not sure about radeon today. The latest alsa driver should handle the audio part.
There are still conflicting reports about whether a DVI output and DVI-to-HDMI adapter works for audio. AFAIK it should (HDMI just multiplexes the audio onto the same pairs as video) but some reports say it doesn't work. Don't know if that was HW or SW though -- but if you have a card with an HDMI connector it should just work.