Zephyr API Function bt_gatt_read Takes long time to return an error code

[wliao]

Hi,

I was doing BLE tests with our custom code using two nrf52dk DK boards. The client keeps reading data from the server every 250ms. If I power reset the server during the client's reading activity, I noticed it took a long time (about 20-30 seconds) for the function bt_gatt_read to return the error code (-12, ENOMEM). Is there any specific reason why it takes so much time?

The SDK I was using is v2.4.0 nRF Connect.

Thanks! 

[Simonr]

Hi

The ATT timeout itself can't be changed, as it's given by the specification, but the allocation timeout could be changed without breaking spec. But you should note that the Bluetooth API is blocking in general, so that might be an issue.

Best regards,

Simon

[wliao]

So why 30 seconds is used for the allocation timeout? Just because it is long enough? Do you have a better solution to the problem I described above to shorten the response time in such situation?

Thanks!