From dd6849da1880c73d66d1c57167b21edc0a626d56 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Wed, 29 Aug 2018 14:01:17 +0200 Subject: [PATCH] lchan: pick proper power and ta values When activating an lchan, the power levels should be maximum and TA zero. Only if a new lchan is assigned within the same cell does it make sense to take over the previous power and TA levels. In LCHAN_EV_ACTIVATE: - Separate the code that copies previous encryption data. This should happen regardless of whether we're staying in the same cell or not. - For the power,TA levels, take over an old lchan's values only when it is assigning a new lchan in the same cell. Change-Id: I360b003398487fa6f934296ff03643c33ec61a35 --- src/osmo-bsc/lchan_fsm.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/src/osmo-bsc/lchan_fsm.c b/src/osmo-bsc/lchan_fsm.c index 3352da59d..7d4738045 100644 --- a/src/osmo-bsc/lchan_fsm.c +++ b/src/osmo-bsc/lchan_fsm.c @@ -429,6 +429,8 @@ static void lchan_fsm_unused(struct osmo_fsm_inst *fi, uint32_t event, void *dat { struct lchan_activate_info *info = data; struct gsm_lchan *lchan = lchan_fi_lchan(fi); + struct gsm_bts *bts = lchan->ts->trx->bts; + switch (event) { case LCHAN_EV_ACTIVATE: @@ -446,18 +448,25 @@ static void lchan_fsm_unused(struct osmo_fsm_inst *fi, uint32_t event, void *dat lchan->activate.concluded = false; lchan->activate.re_use_mgw_endpoint_from_lchan = info->old_lchan; - if (info->old_lchan) { + if (info->old_lchan) lchan->encr = info->old_lchan->encr; + else { + lchan->encr = (struct gsm_encr){ + .alg_id = RSL_ENC_ALG_A5(0), /* no encryption */ + }; + } + + /* If there is a previous lchan, and the new lchan is on the same cell as previous one, + * take over power and TA values. Otherwise, use max power and zero TA. */ + if (info->old_lchan && info->old_lchan->ts->trx->bts == bts) { lchan->ms_power = info->old_lchan->ms_power; lchan->bs_power = info->old_lchan->bs_power; lchan->rqd_ta = info->old_lchan->rqd_ta; } else { - struct gsm_bts *bts = lchan->ts->trx->bts; - lchan->encr = (struct gsm_encr){ - .alg_id = RSL_ENC_ALG_A5(0), /* no encryption */ - }; lchan->ms_power = ms_pwr_ctl_lvl(bts->band, bts->ms_max_power); - lchan->bs_power = 0; /* 0dB reduction, output power = Pn */ + /* From lchan_reset(): + * - bs_power is still zero, 0dB reduction, output power = Pn. + * - TA is still zero, to be determined by RACH. */ } if (info->chan_mode == GSM48_CMODE_SPEECH_AMR)