Comment 2 for bug 1314167

http://www.intel.com/support/motherboards/desktop/sb/cs-015851.htm

did your front audio panel support jack detection ?

your desktop have two capture devices and three input sources

ARECORD

**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC887-VD Analog [ALC887-VD Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 2: ALC887-VD Alt Analog [ALC887-VD Alt Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

how can pulseaudio auto switch the input sources when user plugged in line in and rear Jack at the same time ?

the codec can also be configured to select stereo mixer 0x0b as input by hint

Node 0x22 [Audio Mixer] wcaps 0x20010b: Stereo Amp-In
  Amp-In caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
  Amp-In vals: [0x80 0x80] [0x00 0x00] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]
  Connection: 12
     0x18 0x19 0x1a 0x1b 0x1c 0x1d 0x14 0x15 0x16 0x17 0x0b 0x12
Node 0x23 [Audio Mixer] wcaps 0x20010b: Stereo Amp-In
  Amp-In caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
  Amp-In vals: [0x80 0x80] [0x80 0x80] [0x00 0x00] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]
  Connection: 11
     0x18 0x19 0x1a 0x1b 0x1c 0x1d 0x14 0x15 0x16 0x17 0x0b

control.19 {
  iface MIXER
  name 'Input Source'
  value Line
  comment {
   access 'read write'
   type ENUMERATED
   count 1
   item.0 'Front Mic'
   item.1 'Rear Mic'
   item.2 Line
  }
 }
 control.20 {
  iface MIXER
  name 'Input Source'
  index 1
  value 'Front Mic'
  comment {
   access 'read write'
   type ENUMERATED
   count 1
   item.0 'Front Mic'
   item.1 'Rear Mic'
   item.2 Line
  }
 }