Node 0x18, 0x19, 0x1a and 0x1b have 

  Amp-In caps: ofs=0x00, nsteps=0x03, stepsize=0x27, mute=0
  Amp-In vals:  [0x00 0x00]

as node 0x1b Headphone can be retasked to Headphone Mic , there should be Headphone Mic Boost at node 0x1b


Node 0x18 [Pin Complex] wcaps 0x40058f: Stereo Amp-In Amp-Out
  Control: name="Center Playback Switch", index=0, device=0
    ControlAmp: chs=1, dir=Out, idx=0, ofs=0
  Control: name="LFE Playback Switch", index=0, device=0
    ControlAmp: chs=2, dir=Out, idx=0, ofs=0
  Control: name="Rear Mic Boost Volume", index=0, device=0
    ControlAmp: chs=3, dir=In, idx=0, ofs=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 0x00003734: IN OUT Detect
    Vref caps: HIZ 50 GRD 80 100
  Pin Default 0x01a19020: [Jack] Mic at Ext Rear
    Conn = 1/8, Color = Pink
    DefAssociation = 0x2, Sequence = 0x0
  Pin-ctls: 0x24: IN VREF_80
  Unsolicited: tag=03, enabled=1
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
  Connection: 3
     0x0c* 0x0d 0x0e
Node 0x19 [Pin Complex] wcaps 0x40058f: Stereo Amp-In Amp-Out
  Control: name="Headset Mic Boost Volume", index=0, device=0
    ControlAmp: chs=3, dir=In, idx=0, ofs=0
  Amp-In caps: ofs=0x00, nsteps=0x03, stepsize=0x27, mute=0
  Amp-In vals:  [0x03 0x03]
  Amp-Out caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
  Amp-Out vals:  [0x80 0x80]
  Pincap 0x0000373c: IN OUT HP Detect
    Vref caps: HIZ 50 GRD 80 100
  Pin Default 0x411111f0: [N/A] Speaker at Ext Rear
    Conn = 1/8, Color = Black
    DefAssociation = 0xf, Sequence = 0x0
    Misc = NO_PRESENCE
  Pin-ctls: 0x24: IN VREF_80
  Unsolicited: tag=00, enabled=0
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
  Connection: 3
     0x0c* 0x0d 0x0e
Node 0x1a [Pin Complex] wcaps 0x40058f: Stereo Amp-In Amp-Out
  Control: name="Surround Playback Switch", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=0
  Control: name="Line Boost Volume", index=0, device=0
    ControlAmp: chs=3, dir=In, idx=0, ofs=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 0x00003734: IN OUT Detect
    Vref caps: HIZ 50 GRD 80 100
  Pin Default 0x0181302f: [Jack] Line In at Ext Rear
    Conn = 1/8, Color = Blue
    DefAssociation = 0x2, Sequence = 0xf
  Pin-ctls: 0x20: IN VREF_HIZ
  Unsolicited: tag=04, enabled=1
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
  Connection: 3
     0x0c* 0x0d 0x0e
Node 0x1b [Pin Complex] wcaps 0x40058f: Stereo Amp-In Amp-Out
  Control: name="Headphone Playback Switch", index=0, device=0
    ControlAmp: chs=3, dir=Out, idx=0, ofs=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:  [0x00 0x00]
  Pincap 0x0001373c: IN OUT HP EAPD Detect
    Vref caps: HIZ 50 GRD 80 100
  EAPD 0x2: EAPD
  Pin Default 0x0221401f: [Jack] HP Out at Ext Front
    Conn = 1/8, Color = Green
    DefAssociation = 0x1, Sequence = 0xf
  Pin-ctls: 0xc0: OUT HP VREF_HIZ
  Unsolicited: tag=01, enabled=1
  Power states:  D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
  Connection: 3
     0x0c* 0x0d 0x0e