Hello!
First of all, I use Gentoo Linux with Alsa only setup. No pulseaudio or others. It worked pretty perfect since like forever. Since KDE-4.8 I have an very nasty issue:
Kmix doesn't record properly anymore, I always have to set a slider called digital and another called capture. They are alway set to zero after reboot and thus prevent skype or any other audio-recording software to function. No matter what I set in kmix or alsamixer, it always resets to zero after reboot. I even check the "keep settings" in kmix. Another issue with kmix is that the notification icon always shows the master channel as set to zero, even if the sound is working
Please help.

You probably have the wrong Master channel selected - every driver is different with the names it uses so KMix has to guess I believe - and it seems to have guessed wrong here. Right click on the KMix icon > Select Master Channel.

Thanks for the reply, but this is totally not the point.
Point is, that despite any settings, the microphone channel isn't controlled via "mic" or "internal mic" anymore but instead over "digital" and that I have to set the "capture" channel too, to even get skype or gtalk record anything. Additionally, those sliders "digital" and "capture" are always muted after reboot.
Sice I am using KDE for 10 years or more now, things like setting the master channel are pretty obvious and don't fix anything. The Kmix widget is always displayind soud as "0" no matter which master channel I set there... Because I have sound anyway, I don't care, but the mic problem is nasty.

Have you tried installing KMix from 4.7 to see if that has these issues? (Just to eliminate other changes as the cause of this issue)

Yes I can confirm that: kmix-4.7.4 works like expected and all sliders keep their levels as expected.
Kmix-4.8.0 does not. Sounds like a bug to me, right?

Yes, please file a bug report at bugs.kde.org. It seems that there have been some regressions unfortunately.

Done. Thanks for the hint. Happy with 4.7.4 for now
https://bugs.kde.org/show_bug.cgi?id=294290

You could also try this in 4.8 to see whether that fixes the problem.

For the record: I had no probs moving to 4.8...