Had a tinker, and used both suppress_notify=2 and suppress_notify=0.

This is the output when an action is preformed; "Previous Track"
Code:
  serial_notify_thread.cpp: 116:@@ N1475
  serial_notify_thread.cpp: 117:@@ F0x8010
  serial_notify_thread.cpp: 118:@@ TThe 'in' Crowd
  serial_notify_thread.cpp: 119:@@ ABryan Ferry & Roxy Music
  serial_notify_thread.cpp: 120:@@ GRock/Pop
50943: IA1:00000004,dk=00ffffff,dr=0,lk=0
50943: IA2:00000004.P,dk=00ffffff,dr=0,lk=0
50943: ENQ.I: @c0125740: 00000004.0
50944: DEQ.I: @c0125740: 00000004.0
50944: ENQ.P: @c01258cc: 00000004.0
Poll ok
50945: DEQ.P: @c01258cc: 00000004.0
Poll wait
Poll fail
50963: IA1:00000005,dk=00000004,dr=0,lk=0
50963: IA2:00000005.R,dk=00000004,dr=0,lk=0
50963: ENQ.I: @c0125748: 00000005.0
50965: DEQ.I: @c0125748: 00000005.0
50965: ENQ.P: @c01258d4: 00000005.0
Poll ok
50966: DEQ.P: @c01258d4: 00000005.0
Poll wait
Poll fail
  serial_notify_thread.cpp: 116:@@ N1474
  serial_notify_thread.cpp: 117:@@ F0x2a40
  serial_notify_thread.cpp: 118:@@ TTougher than the rest
  serial_notify_thread.cpp: 119:@@ ABruce Springsteen
  serial_notify_thread.cpp: 120:@@ G
  spindown_chunk_cache_runner.cpp: 294:Filling up space (-16)


This is the output when using the menu, no action performed (i.e. browsing the menu items)
Code:
63046: IA1:00000004,dk=00ffffff,dr=0,lk=0
63046: IA2:00000004.P,dk=00ffffff,dr=0,lk=0
63046: ENQ.I: @c0125790: 00000004.0
63047: DEQ.I: @c0125790: 00000004.0
63048: ENQ.P: @c012591c: 00000004.0
Poll ok
63048: DEQ.P: @c012591c: 00000004.0
Poll wait
Poll fail
63056: IA1:00000005,dk=00000004,dr=0,lk=0
63056: IA2:00000005.R,dk=00000004,dr=0,lk=0
63056: ENQ.I: @c0125798: 00000005.0
63058: DEQ.I: @c0125798: 00000005.0
63058: ENQ.P: @c0125924: 00000005.0
Poll ok
63059: DEQ.P: @c0125924: 00000005.0
Poll wait
Poll fail


From what I can tell 00000004 is pressing left button, and 00000005 is releasing left button, and hijack is outputting that the button was pressed and released, not the action performed by the button (i.e. the context or result of pressing the buttons) ?

I assume this is why there is no "real" output on the Serial interface when audio is changed from Aux to Player?

I did notice that one of the files in /proc has active audio source, but using it would require "something" to poll that file every n seconds and output on the same serial interface (can they be shared?!?) when the audio source changes?


Waiting for a new battery to power the IR remote as I suspect it will work better as it will output "actions", like prev and next. However, the radio will have no way of knowing if its the active audio source or not and any IR actions when in Player mode will also be performed by the Radio.

So... the question is, how hard is it to add "actions" to the serial output?