Comment 39 for bug 1365769

the input mux can select rear mic, front mic , line in and audio mixer node 0x21

this mean that the unavailable line in port cannot be the active port

Node 0x1e [Audio Selector] wcaps 0x300501: Stereo
  Power states: D0 D1 D2 D3
  Power: setting=D0, actual=D0
  Connection: 6
     0x2c 0x2b* 0x2a 0x29 0x28 0x21
Node 0x1f [Audio Selector] wcaps 0x300501: Stereo
  Power states: D0 D1 D2 D3
  Power: setting=D0, actual=D0
  Connection: 6
     0x2c 0x2b* 0x2a 0x29 0x28 0x21

ports:
  analog-input-microphone-front: Front Microphone (priority 8500, latency offset 0 usec, available: no)
   properties:
    device.icon_name = "audio-input-microphone"
  analog-input-microphone-rear: Rear Microphone (priority 8200, latency offset 0 usec, available: no)
   properties:
    device.icon_name = "audio-input-microphone"
  analog-input-linein: Line In (priority 8100, latency offset 0 usec, available: no)
   properties:

 active port: <analog-input-linein>