nRF52840 BLE HID Keyboard can not reconnect after reboot/power-cycle

RE: nRF52840 BLE HID Keyboard can not reconnect after reboot/power-cycle

Kenneth — Thu, 05 Aug 2021 11:18:54 GMT

Can you also test 1.6.1 or master branch for comparison?

Kenneth

RE: nRF52840 BLE HID Keyboard can not reconnect after reboot/power-cycle

Sasa Karanovic — Tue, 03 Aug 2021 15:18:05 GMT

Thanks for sharing that case. I actually found it trough Google search when troubleshooting a different issue (not being able to send keystrokes to iOS device at all). I have tried the proposed solution for EACCESS error but it didn't solve the issue.

I'm using NCS v1.6.0.

Interesting thing is that this check fails only for iOS devices. Android devices work like a charm.

RE: nRF52840 BLE HID Keyboard can not reconnect after reboot/power-cycle

Kenneth — Mon, 02 Aug 2021 16:14:49 GMT

I was thinking it could be a race condition, where you called bt_hids_in_rep_send() prior to the encryption taking place on the link (since that can take some time, e.g. ~100ms after link is established). If that is not the case then I can find an open case with similar symptoms here:
https://devzone.nordicsemi.com/f/nordic-q-a/71151/the-bluetooth-keyboard-sample-does-not-work-in-an-ios-14-3-environment

Maybe your case is the same? Which NCS version are you using?

Kenneth

RE: nRF52840 BLE HID Keyboard can not reconnect after reboot/power-cycle

Sasa Karanovic — Thu, 29 Jul 2021 13:51:26 GMT

That doesn't really answer the question.

What is the proper way of fixing this issue?

Both devices are paired and bonded. Until you reset nRF52, everything works great. However once you reset the DK, phone connects to the device, bonding information is loaded but nRF can't send reports since bt_hids_in_rep_send() returns error.

RE: nRF52840 BLE HID Keyboard can not reconnect after reboot/power-cycle

Kenneth — Thu, 29 Jul 2021 13:11:35 GMT

Ideally you should not call bt_hids_inp_rep_send() until the link is encrypted, because it's only after the link is encrypted that the notification can be sent (in which case the bt_gatt_is_subscribed() should not fail either).

Kenneth