4a-hal-generic: aborting with "Can't enter dispatch while in dispatch!" when a phone is connected via bluetooth

Thierry patched its binding accordlingly to the guidelines above

This happens when connecting to the systemd's event loop of the binder. (see function afb_api_get_event_loop [1]) It that case, it is not possible to call a synchronous call from the callback of the event. The reason is that the call back has to return before the even loop can be used. This limitation comes from systemd (but notice that reading an input in the callback is generally needed to avoid endless call to the event handler callback).

When you do a call_sync in the systemd event handler callback, the binder now emit the message "Can't enter dispatch while in dispatch!" and calls abort.

The implementation of the systemd event handler has to be changed to not block. You can use the asynchronous call variants if needed [2].

[1] http://docs.automotivelinux.org/master/docs/apis_services/en/dev/reference/af-binder/reference-v3/func-api.html#afbapigeteventloop
[2] http://docs.automotivelinux.org/master/docs/apis_services/en/dev/reference/af-binder/reference-v3/func-api.html#afbapicall