nrf9160 lte_lc_init_and_connect() blocks even when running on Zephyr workqueue.

[Jack Panetta]

When my app starts up, I call "lte_lc_init_and_connect()" by using the Zephyr system workqueue. With it running on a separate thread, my main thread is still blocked. I have tried using the CONFIG_LTE_AUTO_INIT_AND_CONNECT, but that is just as annoying because then my application blocks during startup, and I also don't want to connect every time I start up.

Is there anyway to initiate the LTE connection without blocking my whole program?

- Jack

[Håkon Alseth]

Hi,

 

You can set up your application similar to how the asset_tracker is:

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/samples/nrf9160/asset_tracker/src/main.c#L575

CONFIG_LTE_AUTO_INIT_AND_CONNECT=n is then required in your prj.conf.

Could you try this and see if it works per your requirement?

 

Kind regards,

Håkon

[Linus]

I have the exact same problem. I tried to call lte_lc_init_and_connect() in a separate thread, but it still blocks the entire system. I need to perform the connection in the background, because I want the application to run even when the connection fails.

[Håkon Alseth]

This is the call that is performed when you call the function, and k_sleep shall yield for other threads:

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/drivers/lte_link_control/lte_lc.c#L152

Please see my former response on how to configure the lte_lc driver to initialize the LTE connection in main.

 

If you still have issues, please open up a new thread, as this one is quite old.

Kind regards,

Håkon

[Linus]

Hi again. Maybe I'm not understanding things properly (I am new to Zephyr). 

I am using the mqtt_simple sample project as a base, which sets CONFIG_LTE_AUTO_INIT_AND_CONNECT=n in the kernel config. I am then starting a separate thread which calls lte_lc_init_and_connect(), while the main thread sleeps for 10 seconds and calls printk() in a loop, si I can see if it runs.
The end result is that the output from the main thread is not shown until lte_lc_init_and_connect() returns. I have very bad connectivity at the office, so the LTE connection can sometimes take minutes, so I should see several printouts while waiting for the connection.

Regards,

Linus