On my Thinkpad w520 with Nvidia Optimus (using Nvidia properietary drivers) I connected an external monitor via DisplayPort, using a Displayport -> HDMI adapter cable. The monitor has integrated speakers and the first time I did this, sound output worked like a charm
The next day I tried this (powerd up my laptop, hooked it up just like the day before) it stopped working.
Using Kubuntu 14.10.
This is what I see in the audio settings config dialog:
I tried selecting each one of the High Definition Audio Controllers one by one, but none of them seems willing to output any sound when I press the "Test" button.
Using Alsamixer I selected the Nvidia HDA Sound device and this is what I see instead of volume sliders:
I also tried switching from the GStreamer Phonon Backed to VLC but that didn't work either.
Any ideas as to anything else I could try are appreciated. Thanks!