I have an amd radeon hd5450, and a dell u2711. Both support HDMI, and I've connected an hdmi cable b/n the two.

The Dell can take an hdmi signal, and convert that to analog output, it has jacks for this on the screen itself. From there it goes into my speakers.

Problem is that I can only hear audio through my speakers when I am also viewing my ubuntu desktop through HDMI port. When I switch the input on my dell to DVI instead (I also have a dvi cable running from card to monitor), the sound immediately stops playing as soon as the display changes to dvi mode. The funny thing is that the sound signal is still there when viewing video over dvi, if I crank the amp to the max I here the music very faintly, it's like the volume on something gets dropped to just above 0 as soon as I switch to dvi. I checked the sound levels but they are all at max everywhere.

I've played with using alsa instead of pulse audio, switching from kde to unity etc etc, nothing makes a difference.

Is there any way I can use dvi for video while playing sound through hdmi? The reason I want to use dvi for video is because of the higher resolution that dvi supports. Hdmi is limited to 1280 by 1080 whereas my monitor gets 2560 by 1440 when using dvi-d.