bts: Start a DL TBF if needed after establishment of an UL TBF
Currently an existing DL TBF can get lost in the process of
establishing an UL TBF via RACH. This can lead to stalled connections
until the network sends more LLC frames.
This commit adds a check for a non-empty LLC queue after the UL TBF
has been established to rcv_control_ack (GPRS_RLCMAC_UL_ASS_WAIT_ACK
path) to eventually establish a new DL TBF on the UL TBF's PACCH.
Sponsored-by: On-Waves ehf
diff --git a/tests/tbf/TbfTest.err b/tests/tbf/TbfTest.err
index 8401e08..70b5c57 100644
--- a/tests/tbf/TbfTest.err
+++ b/tests/tbf/TbfTest.err
@@ -1825,6 +1825,25 @@
RX: [PCU <- BTS] TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Packet Control Ack
TBF: [DOWNLINK] UPLINK ASSIGNED TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)
TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) changes state from ASSIGN to FLOW
+********** TBF starts here **********
+Allocating DL TBF: MS_CLASS=1
+Slot Allocation (Algorithm A) for class 1
+- Skipping TS 0, because not enabled
+- Skipping TS 1, because not enabled
+- Skipping TS 2, because not enabled
+- Skipping TS 3, because not enabled
+- Skipping TS 4, because not enabled
+- Skipping TS 5, because not enabled
+- Skipping TS 6, because not enabled
+- Assign downlink TS=7 TFI=1
+PDCH(TS 7, TRX 0): Attaching TBF(TFI=1 TLLI=0x00000000 DIR=DL STATE=NULL), 2 TBFs, USFs = 01, TFIs = 00000003.
+- Setting Control TS 7
+Attaching TBF to MS object, TLLI = 0xf1223344, TBF = TBF(TFI=1 TLLI=0xf1223344 DIR=DL STATE=NULL)
+Allocated TBF(TFI=1 TLLI=0xf1223344 DIR=DL STATE=NULL): trx = 0, ul_slots = 80, dl_slots = 80
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Trigger downlink assignment on PACCH
+Send dowlink assignment on PACCH, because TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) exists
+TBF(TFI=1 TLLI=0xf1223344 DIR=DL STATE=NULL) changes state from NULL to ASSIGN
+TBF(TFI=1 TLLI=0xf1223344 DIR=DL STATE=ASSIGN) starting timer 0.
UL DATA TFI=0 received (V(Q)=0 .. V(R)=0)
TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) restarting timer 3169 while old timer 3169 pending
- BSN 0 storing in window (0..63)