Comment 52 for bug 996906

which motherboard are you using ?

do this motherboard support internal spdif connector to graphic card ?

it is rare that it only has internal spdif connector but not optical/rca digital output

You can also connect the onboard header to an S/PDIF input header available on some graphics cards using an S/PDIF cable. This connection routes digital audio to the HDMI output of the graphics card.

http://www.intel.com/support/motherboards/desktop/sb/CS-032871.htm

Node 0x20 [Pin Complex] wcaps 0x400701: Stereo Digital
  Control: name="HDMI Phantom Jack", index=0, device=0
  Pincap 0x00000010: OUT
  Pin Default 0x185600f0: [Jack] Digital Out at Int HDMI
    Conn = Digital, Color = Unknown
    DefAssociation = 0xf, Sequence = 0x0
  Pin-ctls: 0x40: OUT
  Power states: D0 D1 D2 D3
  Power: setting=D0, actual=D0
  Connection: 1
     0x12

APLAY

**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: VT1708S Analog [VT1708S Analog]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 2: VT1708S Alt Analog [VT1708S Alt Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 3: VT1708S Digital [VT1708S Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0