After upgrading from OpenSuSE 10.2 to OpenSuSE 10.3, I had no sound. My sound card is a Via 8233, which uses the Via 82xx driver. I had noticed that the sound in 10.2 was a little faint, but I didn't bother to try to fix it.

I did the alsaconf quadrille, which produced a click but nothing else. Finally I tried configuring the card again in Yast, using the Edit option. I opened the Volume control (under Other) and saw four sliders at the bottom, all labelled VIA DXS. I set them all to the max and when I pressed the test button, the sound blasted out at me. Problem solved!

But the question remains: why are there four separate sliders and what is the difference among them? For that matter, what do they really do?

The existance or otherwise of a particular slider depends on the driver. As for what they do: take a look at the soundcard capabilities. Have you tried muting them one at a time to see what changes?

The first DSX channel seems to set the volume and the others have no effect. Even though I've solved my problem, I'm wondering just what a DSX channel is. Is that particular to the Via 82XX cards or is it a more general term used with soundcards? Neither Google nor Wikipedia was much help on that.

By the way, I posted my query mainly in the hope that it would be useful to others. The questions I asked were out of curiosity, not necessity.

Digital Signals Cross-connect

Thanks, Simon -- but do you know why there are 4 of them, of which only one produces an audible effect?

Well... the card provides 4 DSX channels, perhaps you are not using all the available features of your card?
You did read the documentation?
Is there a man page with the driver?

I didn't think there was any available documentation since the sound chip is on my motherboard and there's no pertinent man page, but I did find it after all. The source code for the driver explains everything. For those interested, it can be found at /usr/src/linux-2.6.22.9-0.4/sound/pci/via82xx.c.