From 526b4a5f350725d312c6739cf6abdcef040b698c Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Tue, 11 Sep 2018 00:47:29 +0200 Subject: ts,lchan_fsm: do not attempt to allocate CBCH subslots In case a given channel combination contains a CBCH, it replaces sub-slot 2 with a CBCH, i.e. we must not attempt to allocate the same for SDCCH. On timeslot initialization, immediately place such an lchan FSM into new state LCHAN_ST_CBCH, so that it never appears unused and never is picked during lchan_select(). Also set lchan->type = GSM_LCHAN_CBCH. Verified by configuring CBCH timeslots and watching 'show lchan summary'. Immediately after RSL and OML are up, these pchan types show lchan 2 in state CBCH: BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm With a 'phys_chan_config ccch+sdcch4+cbch' and three phones simultaneously requesting USSD, I see: BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 0, Type SDCCH, State ESTABLISHED - L1 MS Power: 14 dBm RXL-FULL-dl: -53 dBm RXL-FULL-ul: -47 dBm BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 1, Type SDCCH, State ESTABLISHED - L1 MS Power: 30 dBm RXL-FULL-dl: -47 dBm RXL-FULL-ul: -47 dBm BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm BTS 0, TRX 0, Timeslot 0 CCCH+SDCCH4+CBCH, Lchan 3, Type SDCCH, State ESTABLISHED - L1 MS Power: 16 dBm RXL-FULL-dl: -47 dBm RXL-FULL-ul: -47 dBm With 'phys_chan_config SDCCH8+CBCH' and three phones simultaneously attaching, I see: BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 0, Type SDCCH, State WAIT_RLL_RTP_ESTABLISH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 1, Type SDCCH, State WAIT_RLL_RTP_ESTABLISH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 2, Type CBCH, State CBCH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm BTS 0, TRX 0, Timeslot 1 SDCCH8+CBCH, Lchan 3, Type SDCCH, State WAIT_RLL_RTP_ESTABLISH - L1 MS Power: 0 dBm RXL-FULL-dl: -110 dBm RXL-FULL-ul: -110 dBm i.e. in all cases the CBCH lchan remains occupied and is not allocated as SDCCH. Detaching and re-attaching the BTS reliably brings back the CBCH state. Also verified that changing the osmo-bsc config from telnet vty and dropping oml followed by the BTS re-attaching brings back the CBCH state. Change-Id: I2bafc5f696e818e38f8907ad0c8f38494df0623d --- include/osmocom/bsc/lchan_fsm.h | 1 + src/osmo-bsc/lchan_fsm.c | 7 +++++++ src/osmo-bsc/timeslot_fsm.c | 9 +++++++++ 3 files changed, 17 insertions(+) diff --git a/include/osmocom/bsc/lchan_fsm.h b/include/osmocom/bsc/lchan_fsm.h index 35b88471e..9fbf9b3dc 100644 --- a/include/osmocom/bsc/lchan_fsm.h +++ b/include/osmocom/bsc/lchan_fsm.h @@ -14,6 +14,7 @@ enum lchan_fsm_state { LCHAN_ST_UNUSED, + LCHAN_ST_CBCH, /*< Blocked by CBCH channel combination, not usable as SDCCH. */ LCHAN_ST_WAIT_TS_READY, LCHAN_ST_WAIT_ACTIV_ACK, /*< After RSL Chan Act Ack, lchan is active but RTP not configured. */ LCHAN_ST_WAIT_RLL_RTP_ESTABLISH, diff --git a/src/osmo-bsc/lchan_fsm.c b/src/osmo-bsc/lchan_fsm.c index 1ef7869d3..c80d8a16e 100644 --- a/src/osmo-bsc/lchan_fsm.c +++ b/src/osmo-bsc/lchan_fsm.c @@ -1035,6 +1035,13 @@ static const struct osmo_fsm_state lchan_fsm_states[] = { , .out_state_mask = 0 | S(LCHAN_ST_WAIT_TS_READY) + | S(LCHAN_ST_CBCH) + , + }, + [LCHAN_ST_CBCH] = { + .name = "CBCH", + .out_state_mask = 0 + | S(LCHAN_ST_UNUSED) , }, [LCHAN_ST_WAIT_TS_READY] = { diff --git a/src/osmo-bsc/timeslot_fsm.c b/src/osmo-bsc/timeslot_fsm.c index 56b335773..fc2546003 100644 --- a/src/osmo-bsc/timeslot_fsm.c +++ b/src/osmo-bsc/timeslot_fsm.c @@ -295,6 +295,15 @@ static void ts_fsm_unused_onenter(struct osmo_fsm_inst *fi, uint32_t prev_state) T_CHAN_ACT_DEACT); break; + case GSM_PCHAN_CCCH_SDCCH4_CBCH: + case GSM_PCHAN_SDCCH8_SACCH8C_CBCH: + /* For any pchans containing a CBCH, lchan[2] is reserved for CBCH and cannot be + * allocated for SDCCH. */ + OSMO_ASSERT(ts->lchan[2].fi); + ts->lchan[2].type = GSM_LCHAN_CBCH; + osmo_fsm_inst_state_chg(ts->lchan[2].fi, LCHAN_ST_CBCH, 0, 0); + break; + default: /* nothing to do */ break; -- cgit v1.2.3