I have Kubuntu 14.04 64-bit on an AMD box. I have Coax Digital IEC958 sound output to an audio receiver. After startup, sound works for a while (10-15 min), and thereafter (kmix) volume falls to zero - no sound thereafter. I can adjust sound in kmix, but it will invariably do the same thing.
I cannot find any relevant messages in dmesg or syslog.
I have Asus K55V, fedora 17 64 biti instaled. I have audio from laptop, but I canot use an audio sistem because when I connect the audio jack in audio out port, it doesn't get out any sound anymore. The sound from laptop stops and audio sistem doesn't work either. In win 7 it works OK. The sound hard from my laptop is provided by realteck.