i have been breaking my back and racking my brain for the past few days over this issue. I have made some considerable progress.

I have this nifty HDMI port that is sending video/audio from my slackware box to my samsung television. I've installed the ATI drivers and configured X properly. My issue is setting the HDMI device as the default pcm output. Any console apps (e.g. mplayer, aplay, speaker-test) work just fine, sound plays perfectly (though stereo only, but that's another issue for another time). However editing /etc/asound.conf or /usr/share/alsa/alsa.conf to change the default pcm card/device screws up KDE4's Sound System in such a way that either the HDMI device just "dosen't work" and reverts to the regular analog output, or "this device has been removed from your system". I can get XMMS to play sound through HDMI which will work for now, but i'm hung on getting sound to play in my web browser as well, and for other KDE apps as it should.

Any ideas on how I can work around KDE being a pain in the rear?

Edit: the topic should read ATI Radeon 4200.

If you bring up system settings->multimedia->Audio output, what items are listed?

it lists the HDA ati HDMI output, ati sb analog, and "esound"

i can select the hdmi output, and test it successfully, i've even moved it up to the top in preference order. but no sound from the web browser or even system applications.