<p>neels has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/c/osmo-bts/+/21275">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">part 2 of: fix SAPIs for handover, osmo-bts-sysmo<br><br>Change-Id: I30e2ca003a3b15766d9d9dcf529fb2157523758f<br>---<br>M src/osmo-bts-sysmo/oml.c<br>1 file changed, 25 insertions(+), 17 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/75/21275/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/src/osmo-bts-sysmo/oml.c b/src/osmo-bts-sysmo/oml.c</span><br><span>index 6121f76..a4dc31e 100644</span><br><span>--- a/src/osmo-bts-sysmo/oml.c</span><br><span>+++ b/src/osmo-bts-sysmo/oml.c</span><br><span>@@ -657,10 +657,6 @@</span><br><span> #endif</span><br><span> };</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-static const struct sapi_dir ho_sapis[] = {</span><br><span style="color: hsl(0, 100%, 40%);">- { GsmL1_Sapi_Rach, GsmL1_Dir_RxUplink },</span><br><span style="color: hsl(0, 100%, 40%);">-};</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span> struct lchan_sapis {</span><br><span> const struct sapi_dir *sapis;</span><br><span> unsigned int num_sapis;</span><br><span>@@ -693,11 +689,6 @@</span><br><span> },</span><br><span> };</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-static const struct lchan_sapis sapis_for_ho = {</span><br><span style="color: hsl(0, 100%, 40%);">- .sapis = ho_sapis,</span><br><span style="color: hsl(0, 100%, 40%);">- .num_sapis = ARRAY_SIZE(ho_sapis),</span><br><span style="color: hsl(0, 100%, 40%);">-};</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span> static int mph_send_activate_req(struct gsm_lchan *lchan, struct sapi_cmd *cmd);</span><br><span> static int mph_send_deactivate_req(struct gsm_lchan *lchan, struct sapi_cmd *cmd);</span><br><span> static int mph_send_config_ciphering(struct gsm_lchan *lchan, struct sapi_cmd *cmd);</span><br><span>@@ -1176,10 +1167,10 @@</span><br><span> "%s Trying to activate lchan, but commands in queue\n",</span><br><span> gsm_lchan_name(lchan));</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* override the regular SAPIs if this is the first hand-over</span><br><span style="color: hsl(0, 100%, 40%);">- * related activation of the LCHAN */</span><br><span style="color: hsl(120, 100%, 40%);">+ /* For handover, always start the main channel immediately. lchan->dl_sacch.want_active indicates whether dl</span><br><span style="color: hsl(120, 100%, 40%);">+ * SACCH should be activated. Also, for HO, start the RACH SAPI. */</span><br><span> if (lchan->ho.active == HANDOVER_ENABLED)</span><br><span style="color: hsl(0, 100%, 40%);">- s4l = &sapis_for_ho;</span><br><span style="color: hsl(120, 100%, 40%);">+ enqueue_sapi_act_cmd(lchan, GsmL1_Sapi_Rach, GsmL1_Dir_RxUplink);</span><br><span> </span><br><span> for (i = 0; i < s4l->num_sapis; i++) {</span><br><span> int sapi = s4l->sapis[i].sapi;</span><br><span>@@ -1192,6 +1183,14 @@</span><br><span> fl1h->alive_prim_cnt = 0;</span><br><span> osmo_timer_schedule(&fl1h->alive_timer, 5, 0);</span><br><span> }</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* For handover, possibly postpone activating the dl SACCH until the HO RACH is received. */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (sapi == GsmL1_Sapi_Sacch && dir == GsmL1_Dir_TxDownlink) {</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!lchan->dl_sacch.want_active)</span><br><span style="color: hsl(120, 100%, 40%);">+ continue;</span><br><span style="color: hsl(120, 100%, 40%);">+ else</span><br><span style="color: hsl(120, 100%, 40%);">+ lchan->dl_sacch.activated = true;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> enqueue_sapi_act_cmd(lchan, sapi, dir);</span><br><span> }</span><br><span> </span><br><span>@@ -1880,11 +1879,20 @@</span><br><span> /* Give up listening to RACH bursts */</span><br><span> release_sapi_ul_rach(lchan);</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- /* Activate the normal SAPIs */</span><br><span style="color: hsl(0, 100%, 40%);">- for (i = 0; i < s4l->num_sapis; i++) {</span><br><span style="color: hsl(0, 100%, 40%);">- int sapi = s4l->sapis[i].sapi;</span><br><span style="color: hsl(0, 100%, 40%);">- int dir = s4l->sapis[i].dir;</span><br><span style="color: hsl(0, 100%, 40%);">- enqueue_sapi_act_cmd(lchan, sapi, dir);</span><br><span style="color: hsl(120, 100%, 40%);">+ /* All the normal SAPIs have already been activated, only DL SACCH may still be missing.</span><br><span style="color: hsl(120, 100%, 40%);">+ *</span><br><span style="color: hsl(120, 100%, 40%);">+ * Note: theoretically, it would only be necessary to activate the DL SACCH when it is not active yet, i.e.</span><br><span style="color: hsl(120, 100%, 40%);">+ * dl_sacch.activated == false. With repeated HO RACH received, we shouldn't need to re-send the SAPI activation</span><br><span style="color: hsl(120, 100%, 40%);">+ * every time. However, tests with sysmoBTS show that when sending this SAPI activation only once, the lchan</span><br><span style="color: hsl(120, 100%, 40%);">+ * will release some seconds after a handover, with error messages indicating</span><br><span style="color: hsl(120, 100%, 40%);">+ * "Lost SACCH block, faking meas reports and ms pwr".</span><br><span style="color: hsl(120, 100%, 40%);">+ * When re-sending the SAPI activation for every RACH received, the problem goes away.</span><br><span style="color: hsl(120, 100%, 40%);">+ * Before introducing lchan->dl_sacch.want_active, this code here would activate all SAPIs for the main channel,</span><br><span style="color: hsl(120, 100%, 40%);">+ * which would also repeat for each RACH received. Now we only activate DL SACCH here.</span><br><span style="color: hsl(120, 100%, 40%);">+ */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (lchan->dl_sacch.want_active) {</span><br><span style="color: hsl(120, 100%, 40%);">+ enqueue_sapi_act_cmd(lchan, GsmL1_Sapi_Sacch, GsmL1_Dir_TxDownlink);</span><br><span style="color: hsl(120, 100%, 40%);">+ lchan->dl_sacch.activated = true;</span><br><span> }</span><br><span> </span><br><span> return 0;</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-bts/+/21275">change 21275</a>. To unsubscribe, or for help writing mail filters, visit <a href="https://gerrit.osmocom.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.osmocom.org/c/osmo-bts/+/21275"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: osmo-bts </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I30e2ca003a3b15766d9d9dcf529fb2157523758f </div>
<div style="display:none"> Gerrit-Change-Number: 21275 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: neels <nhofmeyr@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>