PulseAudio is used for handling all audio on postmarketOS.
This also involves Bluetooth audio such as A2DP, HSP and HFP audio.
In the case of HFP/HSP, the HF and AG can interact with each other
through AT commands defined in the Bluetooth HFP 1.8 spec.
This set of patches implements HFP support to allow Bluetooth devices
to accept/reject/hangup calls, dial numbers, DTMF tone generation,
query signal strength, roaming status, service status, AG battery level,
call status, etc.
More details in the upstream MR:
https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/693
Available in edge for testing this merge request with a broader user
base. Not intended for backporting to stable branches.
[ci:skip-build]: already built successfully in CI
