Comment 10 for bug 91324

Currently your 'Line' element is toggled for capture:

Simple mixer control 'Line',0
  Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 31 [100%] [12.00dB] [on] Capture [on] <--
  Front Right: Playback 31 [100%] [12.00dB] [on] Capture [on] <--

Note also that your 'IEC958' (optical output) element is unmuted for playback, which is known to affect functionality:

Simple mixer control 'IEC958',0
  Capabilities: pswitch pswitch-joined cswitch cswitch-joined
  Playback channels: Mono
  Capture channels: Mono
  Mono: Playback [on] Capture [off]

Is the above setting intentional?