bt_ctlr_hci: Tx Buffer Overflow on LL/CON/MAS/BV-04-C, LL/CON/SLA/BV-05-C & LL/CON/SLA/BV-06-C

[aescolar]

Describe the bug
At some point during the last couple of week in master LL/CON/MAS/BV-04-C, LL/CON/SLA/BV-05-C & LL/CON/SLA/BV-06-C started failing

To Reproduce
The fastest way, would be to

1. take this branch: Add EDTT tests (BT controller conformance) to CI #21006
2. west update
3. source zephyr-env.sh
4. WORK_DIR=${ZEPHYR_BASE}/bsim_bt_out tests/bluetooth/bsim_bt/compile.sh
5. export EDTT_PATH=${ZEPHYR_BASE}/../tools/EDTT/
6. tests/bluetooth/bsim_bt/edtt_ble_test_app/tests_scripts/ll.1.sh
7. See error in the log

To narrow the run to just one the failing cases, you can edit
tests/bluetooth/bsim_bt/edtt_ble_test_app/tests_scripts/ll.set1.test_list
to only include one of those failing tests (just delete or comment all other lines)

Expected behavior
No errors, testcase passing

Impact
It would seem the controller will not pass certification

Screenshots or console output

LL/CON/MAS/BV-04-C [Master receiving Data packets from Slave] test started...
d_01: @00:03:52.498407  [00:03:52.498,382] <inf> bt_ctlr_hci: handle: 0x0000, rssi: -35 dB.
d_02: @00:03:52.498404  [00:03:52.498,382] <inf> bt_ctlr_hci: handle: 0x0000, rssi: -35 dB.
d_02: @00:03:52.855773  Failed to send ACL Data (err -22)
d_02: @00:03:53.135192  Failed to send ACL Data (err -22)
d_02: @00:03:53.414611  Failed to send ACL Data (err -22)
d_02: @00:03:53.694030  Failed to send ACL Data (err -22)
d_02: @00:03:53.973449  Failed to send ACL Data (err -22)
d_02: @00:03:54.252868  Failed to send ACL Data (err -22)
d_02: @00:03:54.512329  Failed to send ACL Data (err -22)
d_02: @00:03:54.791748  [00:03:54.791,748] <err> bt_ctlr_hci: Tx Buffer Overflow
d_02: @00:03:54.791748  Failed to send ACL Data (err -105)
d_02: @00:03:54.851623  [00:03:54.851,623] <err> bt_ctlr_hci: Tx Buffer Overflow
d_02: @00:03:54.851623  Failed to send ACL Data (err -105)
d_02: @00:03:54.911499  [00:03:54.911,499] <err> bt_ctlr_hci: Tx Buffer Overflow
d_02: @00:03:54.911499  Failed to send ACL Data (err -105)
d_02: @00:03:54.971374  [00:03:54.971,374] <err> bt_ctlr_hci: Tx Buffer Overflow
d_02: @00:03:54.971374  Failed to send ACL Data (err -105)

Environment:

• OS: Linux (Ubuntu 18.04)
• Toolchain: host gcc
• Commit SHA: (today's master) 9a111df

[cvinayak]

The said test cases LL/CON/MAS/BV-04-C, LL/CON/SLA/BV-05-C & LL/CON/SLA/BV-06-C, all passed on EBQ tester 2019-1.7263

Investigation in progress as to why they fail in EDTT framework. I am suspecting either the readBufferSize and number of completed packets count or buffer allocation in the EDTT target application is not being respected correctly.

The failure is due to changes in a1d73ac which fixes the PB flags checks, disallowing the ACL START and only allowing ACL_START_NO_FLUSH for BLE HCI data.

[aescolar]

Fixed by EDTTool/EDTT#1