Issue with nrf_sdh_enable_request() after adding DEBUG_NRF to project configuration

[Aviv Okon]

Hi

I've been working on a project over the past few months, and per a new requirement I was asked to add a debug configuration, as thus far I have worked with only a release configuration

I have a few asserts in code that I wanted to check, so alongside DEBUG I've also added DEBUG_NRF to my project, and this causes an issue where my project stops working by reaching the error while loop inside app_error_save_and_stop()

following the code in debug mode, I found what appears to be the function call that causes the error

while initializing the BLE module, I call ble_stack_init() which begins by calling nrf_sdh_enable_request()

at the end of this function is the following call: sdh_state_observer_notify(NRF_SDH_EVT_STATE_ENABLED);

for some reason I can't explain, it seems that the third iteration inside the loop fails when calling handler(evt, p_observer->p_context) inside this function, but only in this case

and as sdh_state_observer_notify() is called 3 times within nrf_sdh_enable_request() and there previous two seem to work correctly, I really have no idea what could cause this issue

The project works fine without DEBUG_NRF, it is a FreeRTOS project based on the ble_app_hrs_freertos example, though it has changed significantly

Please let me know what further information I can provide that might help determine the source of the problem, and I'll provide it as soon as I can

Thanks

Aviv

[Aviv Okon]

I've done some further testing:

I've disabled all of my API calls in main(), so that only log_init() and clock_init() happen before initializing the BLE module, and yet the code still has the same error in the same function call

I did open the ble_app_hrs_freertos example from the SDK and tried running it in debug configuration, and in that example these functions worked (it failed afterwards, but I would suspect this due to the fact I'm running on a PCB rather than the nRF52840 DK)

these tests lead me to believe that this has something to do with the project configurations, specifically in sdk_config.h, so I've attached it below. hopefully this will provide some clues regarding the possible issues

0028.sdk_config.h

[Susheel Nuguru]

for some reason I can't explain, it seems that the third iteration inside the loop fails when calling handler(evt, p_observer->p_context) inside this function, but only in this case

 The handler has to be some function that is registered previously using NRF_SDH_STATE_OBSERVER. If you step into the handler function then you should get the proper context of which callback function caused the error in the third loop.

[Aviv Okon]

thanks for the answer Susheel

however, I think this problem has nothing to do with anything related to your code

I am working on the project with a team, and one of them has decided to touch the project file and create a unified solution to hold the several project files (in SES)

this commit caused this issue somehow

so I think it is safe to say that I need to discuss this change with the rest of the team, and find what exactly happened that could cause this issue. so I don't think there is any reason to involve you any further, it is clearly a bug in our project locally

please consider the issue resolved from your end

if I do determine the cause of the issue, I'll do my best to post it here, to prevent others from making the same mistake

[Susheel Nuguru]

Thank you very much, Aviv, for being very honest and letting me know what you think the root cause could be. 

I will still keep this thread open and I would request you to come back to this thread once you find out the cause just to make this thread and my curiosity end :)

[Aviv Okon]

I believe I found the real problem and managed to solve it, but it is quite bizzare

In this project I have a specific mode that is built around the USB CDC CLI module

This mode is enabled if a USB cable is detected at the start of the project, through a GPIO pin in our PCB

However, because it is comfortable to test all flows with USB connected (as that is also a way to provide power to the PCB), we've added a define that allows us to disable the USB check and the related mode

for some reason, in debug mode, if the USB CDC driver and USB CLI module weren't initialized, I would get the error I described. I am not sure why this is the case, but I managed to solve it by initializing both regardless, and if I do not intend to use these modules I just uninitialize them

could this be because the USB CDC is based on the app_usbd module, and for some reason if it is enabled in sdk_config.h it is required to be initialized in debug mode?

I would love to hear any possible explanations for this, as I have none myself