During a Mobile Originating voice call, we would normally start
receiving traffic indications with ringback tone (or even some
melody) before the call gets CONNECTed. So in order for the user
to be able to hear that, we need to init the voice call handler
earlier (on receipt of CC ALERTING message).
We should not be transmitting voice/data frames before the call
gets CONNECTed, so add 'rx_only' flag to the TCH state. In
tch_send_msg() drop msgb if this flag is set.
Rx only mode makes no sense for data calls, so in tch_recv_cb() we
discard received DL frames and thus do not trigger sending UL frames.
Change-Id: Idd32c823639cc1f9999d77fcefe7e260e31a85ec
Related: OS#4396
Vadim Yanitskiy
40b0a9094e