Headset jack events emit 2 events: 'Headset Microphone Jack'
and 'Headphone Jack'. These were properly detected before,
but not headphone jack events only: 'Headphone Jack'.
This change allows to detect headphone jack events as well
and act on these events by setting the headphones as
default audio output while keeping the internal
microphone as audio input. For headsets,
the microphone is switched to the headset microphone as well.
We used to have it at 40% and just bumped it to 100%. With 100%, I can
hear static noise in the headphones when using the PinePhone (pmOS CE)
in a silent room, even if I turn the volume down in Pulseaudio (e.g.
18%-30% in Phosh). This was not the case when we had it at 40%.
70% seems to be the sweet spot, where no static noise can be heard when
using headphones in a silent room, but where volume can still be turned
up to a very high level if necessary.
