Comment # 6 on bug 972238 from Takashi Iwai

Then let's start debugging from the very basic stuff.
At first, give alsa-info.sh output on your machine at the mute status.  Do
mixer mute as you did, then run the script with --no-upload option.  Upload
(don't paste) the output file to this bugzilla.

Then, try the command below on a terminal:
  aplay -v /usr/share/sounds/alsa/test.wav
(or you can play any your favorite WAV file there.)  
Does it unmute?  Also, does it show using the pulse plugin, or is it with dmix?

The next is to test paplay.  Run
  paplay /usr/share/sounds/alsa/test.wav
Does this show the auto-unmute behavior?