Comment # 15 on bug 1098912 from Takashi Iwai

Sorry, I forgot to put 0 as the third argument.
And in your case, it's not /dev/hwC0D0 but /dev/hwC1D0. 

  hda-verb /dev/snd/hwC1D0 0x15 GET_PIN_SENSE 0

If this doesn't show any changes in all pins, try to trigger the detection and
read the value
    hda-verb /dev/snd/hwC1D0 0x15 SET_PIN_SENSE 0
    hda-verb /dev/snd/hwC1D0 0x15 GET_PIN_SENSE 0