comments: describe some lchan details

(requested by pespin)

Change-Id: I04ec4ce1fd2b7b110bb496186aae39ecfbbc3628

include/osmocom/bsc/gsm_data.h

@@ -509,10 +509,13 @@ struct lchan_activate_info {
 	/* This always is for a specific lchan, so its lchan->type indicates full or half rate.
 	 * When a dyn TS was selected, the lchan->type has been set to the desired rate. */
 	enum gsm48_chan_mode chan_mode;
+	/* AMR config */
 	uint16_t s15_s0;
 	bool requires_voice_stream;
 	bool wait_before_switching_rtp; /*< true = requires LCHAN_EV_READY_TO_SWITCH_RTP */
 	uint16_t msc_assigned_cic;
+	/* During intra-BSC handover, we keep the MGW endpoint intact and just re-route to the new lchan. This
+	 * activate_info is for the new lchan, the re_use_mgw_endpoint_from_lchan points at the old lchan. */
 	struct gsm_lchan *re_use_mgw_endpoint_from_lchan;
 };
 

src/osmo-bsc/lchan_fsm.c

@@ -547,7 +547,7 @@ static void lchan_fsm_wait_ts_ready_onenter(struct osmo_fsm_inst *fi, uint32_t p
 		lchan->rqd_ta = old_lchan->rqd_ta;
 	} else {
 		lchan->ms_power = ms_pwr_ctl_lvl(bts->band, bts->ms_max_power);
-		/* From lchan_reset():
+		/* Upon last entering the UNUSED state, from lchan_reset():
 		 * - bs_power is still zero, 0dB reduction, output power = Pn.
 		 * - TA is still zero, to be determined by RACH. */
 	}