Comment 119 for bug 946232

the mic pin support impedence sense which alllow the driver which kind of jack plugged since mic has higher impedance than the other jack

Node 0x0e [Pin Complex] wcaps 0x400181: Stereo
  Control: name="Mic Jack Mode", index=0, device=0
    ControlAmp: chs=0, dir=In, idx=0, ofs=0
  Control: name="Mic Phantom Jack", index=0, device=0
  Pincap 0x00001737: IN OUT Detect Trigger ImpSense
    Vref caps: HIZ 50 GRD 80
  Pin Default 0x02a79130: [Jack] Mic at Ext Front
    Conn = Analog, Color = Pink
    DefAssociation = 0x3, Sequence = 0x0
    Misc = NO_PRESENCE
  Pin-ctls: 0x22: IN VREF_GRD
  Unsolicited: tag=00, enabled=0
  Connection: 1
     0x04r