Getting channel sounding start_simple_cs_test working in zephyr bluetooth shell

[psychogenic]

How can you get the simple channel sounding test going with the bluetooth/cs shell commands?  

I've got the shell working over UART and devices talking with each other but can never get passed:

Received subevent results.
Subevent Header:
- Procedure Counter: 0
- Frequency Compensation: 0x0000
- Reference Power Level: -61
- Procedure Done Status: 0x00
- Subevent Done Status: 0x0f
- Procedure Abort Reason: 0x00
- Subevent Abort Reason: 0x02
- Number of Antenna Paths: 1
- Number of Steps Reported: 3
Subevent results contained step data:
- Step mode 0
- Step channel 52
- Step data hexdump:
00000000: 02 7f 01 f0 58 |....|
Subevent results contained step data:
- Step mode 0
- Step channel 9
- Step data hexdump:
00000000: 02 7f 01 f0 58 |....|
Subevent results contained step data:
- Step mode 0
- Step channel 62
- Step data hexdump:
00000000: 02 7f 01 f0 58 |....|
uart:~$

This is aborting for reason 0x02, i.e. BT_HCI_LE_CS_PROCEDURE_ABORT_REASON_TOO_FEW_CHANNELS.  I've tried messing with the internals to get more channels enabled than the default to wind up with a config something like this:

- ID: 0
- Role: Initiator
- Main mode: 2 (PBR)
- Sub mode: 1 (RTT)
- RTT type: AA only
- Main mode steps: 2 - 3
- Main mode repetition: 3
- Mode 0 steps: 3
- CS sync PHY: LE 1M PHY
- T_IP1 time: 60
- T_IP2 time: 30
- T_FCS time: 80
- T_PM time: 20
- Channel map: 0x1FFFFFFFFFFFFC7FFFFC
- Channel map repetition: 3
- Channel selection type: Algorithm #3b
- Ch3c shape: Hat shape
- Ch3c jump: 2

but it just never works.  Perhaps I'm missing something with the sequence of shell commands--the commands are all there, but there aren't any examples of actually using anything.  So I've worked out the following sequence:

bt init

bt connect-name MY_REFLECTOR

bt security 2

cs read_remote_supported_capabilities

cs set_default_settings true false 0x01 -20

cs security_enable

cs default_config initiator local-remote

cs create_config 0 local-only initiator pbr-rtt aa-only

cs set_procedure_parameters

cs start_simple_cs_test 0

Has anyone got the CS start_simple_cs_test actually working and can you specify how you managed to do so/anything you see in the above I'm doing wrong.

Thanks,

PatD

[Simonr]

Hi

Sorry, I guess that description was a bit overly technical.

I don't have a sample on how to do so, and as far as I know we haven't done this yet, no. Can you share a snippet of your code showing how the channel sounding synchronization is done on your end and we will try to see what needs to be done here.

Best regards,

Simon

[psychogenic]

Hi,

I don't think I've been too clear with this, sorry. 

I don't have any code that you don't have: the zephyr/subsys/bluetooth/host/shell/cs.c file mentioned above (which has the channel sounding uart interface for the bt shell) is "Copyright (c) 2024 Nordic Semiconductor ASA" -- am assuming someone tried it out before releasing it, so what I'd like is just to know the sequence of commands to issue in the uart to actually get a successful test going, past the first three mode0 events to some actual ranging.

[Elfving]

Sorry about the wait Pat, I'll taking over this case for a bit.

Could you try using: cs create_config 0 local-remote initiator pbr-rtt aa-only?

Regards,

Elfving

[psychogenic]

What I'd really love is for someone to try and get it working on their side and then show me how they did it. 

To answer: yes, I did try.  Which is how I found the persistent bug at 
https://github.com/zephyrproject-rtos/zephyr/blob/main/subsys/bluetooth/host/shell/cs.c#L296
 

where the code will never accept local-remote as a parameter.  Even fixed, this doesn't make any difference.

[Elfving]

Could you try returning the value in the LE CS Config Complete event on both sides of the connection?