Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

RE: Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

Sam123 — Wed, 16 Apr 2025 17:54:13 GMT

Hi Simon,

Initially, when I had the error I increased the sleep time from 1 second to 2 seconds but it didn't help and the error happened again. Other than that, there was not difference. Currently, the sleep time is back to 1 second and there is no error.

Since the error doesn't happen anymore, lets close this issue. I will follow up if it happens again.

Thanks,

Sam

RE: Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

Simonr — Wed, 16 Apr 2025 10:00:15 GMT

Noted, do you want to dig further into why this might be or should we leave it and close the case since it apparently seems to work now.

Is there any difference in the k_sleep call you did previously and the one implemented now perhaps?

Best regards,

Simon

RE: Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

Sam123 — Tue, 15 Apr 2025 15:47:02 GMT

Hi Simon,

The only difference was the call to k_sleep. I didn't do any other change.

Thanks,

Sam

RE: Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

Simonr — Tue, 15 Apr 2025 13:07:34 GMT

This sounds very strange indeed, but if you're now not able to reproduce this it might have been a typo in your initial project resulting in this. Was this indeed the only difference between yours and the solution main.c?

Best regards,

Simon

RE: Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

Sam123 — Mon, 14 Apr 2025 17:30:23 GMT

Hi Simon,

In my case I didn't pass a number instead of of a struct to bt_conn_le_data_len_update(). I tried the suggested solution to the exercise that I had previously downloaded and the error didn't happen. Then I compared the solution source code in main.c to my owm main.c. The difference was that in the solution k_sleep(K_MSEC(2000)) was not present. So I tried without k_sleep call and it worked. However, I noticed that the call to k_sleep has been added to the solution 5 days ago, so I tried again my code with the call to k_sleep and this time it worked! Not sure what's going on.

RE: Bluetooth fundamental course: Lesson3_Exercise2: data_len_update failed (err -5)

Simonr — Mon, 14 Apr 2025 10:35:31 GMT

The same error message(-5 EIO) seems to be reported in this ticket, where a user was inputting a number instead of a struct to bt_conn_le_data_len_update(). Do you get a build warning about this as well perhaps? You can also check out the suggested solution to the exercise available here and see if the data length update is done similarly or not there.

Best regards,

Simon