Comment 5 for bug 1314167

if your computer chassis do not have hda front audio panel and the front mic jack always return false

pulseaudio treat the front mic jack is not plugged

you need to disable the creation of jack detection control by set bit 8 of pin default

Node 0x19 [Pin Complex] wcaps 0x40058f: Stereo Amp-In Amp-Out
  Control: name="Front Mic Boost Volume", index=0, device=0
    ControlAmp: chs=3, dir=In, idx=0, ofs=0
  Control: name="Front Mic Jack", index=0, device=0
  Amp-In caps: ofs=0x00, nsteps=0x03, stepsize=0x27, mute=0
  Amp-In vals: [0x00 0x00]
  Amp-Out caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
  Amp-Out vals: [0x80 0x80]
  Pincap 0x0000373e: IN OUT HP Detect Trigger
    Vref caps: HIZ 50 GRD 80 100
  Pin Default 0x02a19c50: [Jack] Mic at Ext Front
    Conn = 1/8, Color = Pink
    DefAssociation = 0x5, Sequence = 0x0
  Pin-ctls: 0x24: IN VREF_80
  Unsolicited: tag=02, enabled=1
  Power states: D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
  Connection: 5
     0x0c* 0x0d 0x0e 0x0f 0x26

control.35 {
  iface CARD
  name 'Front Mic Jack'
  value false
  comment {
   access read
   type BOOLEAN
   count 1
  }
 }
 control.36 {
  iface CARD
  name 'Rear Mic Jack'
  value false
  comment {
   access read
   type BOOLEAN
   count 1
  }
 }
 control.37 {
  iface CARD
  name 'Line Jack'
  value false
  comment {
   access read
   type BOOLEAN
   count 1
  }
 }