I've also figured out how jack-detect works, since the codec's GPIO1 is used for the external-hp-amp enable, the jack-detect signals are directly connected to the Bay Trail SoC's GPIOs:
-gpioget 'INT33FC:02' 14 && gpioget 'INT33FC:00' 0 && gpioget 'INT33FC:00' 3 Nothing inserted: 1 1 0 Headset in dock: 0 1 0 Headphon in dock: 0 1 1 Headset in tabl: 1 0 0 Headphon in tabl: 1 0 0 Conclusion: GPO2 pin 14: !jack in dock GPO0 pin 0: !jack in tablet GPO0 pin 3: 1 when jack in dock with no mic
I am a bit confused about the logic. Could you have a case with 1 1 1 (separate headphones in tablet and dock jacks)?
And I believe that the mic on the tablet jack can be detected using the normal micBIAS over current detection which is normally also used.
This will require some special jack-detect handling inside the machine driver for this model. I plan to also add support for this when I have some time to work on this. """
So ATM this requires an explicit user-choice, but I plan to add support for jack-detect on both jacks when I've some more time to work on this.
Thanks!