Regression: Keyboard+Joystick BT/BLE connection stops working in v4.5.0+

[dmik]

I have two boards: Raspberry Pi Pico 2W (RP2350) and Raspberry Pi Pico W (RP2040). Connecting a BLE keyboard to them works in v4.4.4 and below but stops working in v4.5.0 and above (up to the latest v5.4.1).

Note that BluetoothHIDMaster::connectBLE() properly returns true in any of the versions I tried as soon as I put the keyboard into pairing mode. However, in versions 4.5.0 and above, BluetoothHIDMaster::connected() never returns true after that and onKey* and onMouse* callbacks are never called. In v4.4.4 and below, everything works as expected.

Reproducibility is 100% here, it doesn't make any difference which of the boards I try and which of the keyboards I try to connect to them (I have two completely different BLE keyboards).

[dmik]

From what I see in v4.4.4 → 4.5.0 changeling, Pico SDK was updated from 2.1.0 to 2.1.2-develop and no visible changes in the BLE part anywhere else. May be this is the problem.

[maxgerhardt]

So what you're saying is, ever since the March 11 release (7 months ago), our BLE keyboard example just stopped working?

So this is reproducable with https://github.com/earlephilhower/arduino-pico/blob/master/libraries/KeyboardBLE/examples/BLEKeyboardPassword/BLEKeyboardPassword.ino?

[maxgerhardt]

Interesting, with the sketch above, and of course the Tools -> "IP/Bluetooth stack" set to "IPv4 + Bluetooth", I can confirm that on my Raspberry Pi Pico W and Pimoroni Pico Plus 2W (RP2350), uploading the above sketch in 5.4.1 leads to a Bluetooth device that can be paired with, but pressing the BOOTSEL button doesn't type the text. The battery percentage is however changed randomly on each BOOTSEL press and is also reflected in Windows (10).

[earlephilhower]

Some very quick testing on git master seems to point to a problem only with the Keyboard interface portion.

• KeyboardBT and KeyboardBLE both pair but fail to transmit keyboard events
• SerialBT, which uses the SPP on classic BT, does work fine, though.
• MouseBLE and MouseBT work fine

So, HID and HoG (HID over GATT, which is what BLE uses for HID devices) works since that's what the Mouse uses, as well as other plain BT classic profiles and GATT (which is how battery is sent in BLE).

[earlephilhower]

Concur with your assessment, @dmik, and thanks for narrowing it down to a specific revision. 4.4.4->4.5.0 was minor except for the SDK update: 4.4.4...4.5.0

Keyboard differs from Mouse in that it has 2 reports (one for keyboard, one for "consumer keys" like VolumeUp).

Unfortunately it's not (only) that because I just saw JoystickBT/BLE also fail (while Joystick-USB is fine and dandy).

So we have a case of HID sometimes working, consistently....puzzling!

[earlephilhower]

Well, that was silly. Nothing wrong w/BTStack interface, just not calling the virtual parent's ::begin so the _running flag wasn't set in the Keyboard or Joystick. I ran #3222 with all 6 BT/BLE HIDs and it looks fine now.

[earlephilhower]

Looking thru the code trying to figure out how it ever worked, I think it started failing with the first of many "build USB dynamically" patches where I added more code to sanity check we were alive before trying to do HID ops.
earlephilhower/Keyboard@3635ab6

Without those if (!_running) checks we would happily work w/o actually setting the _running flag anywhere.

[dmik]

I'm sorry for not being fully clear with my report. I'm talking about Pico acting as a BLE host (i.e. when a BLE keyboard is connected to it and transmits key/mouse events that it should receive). What you fixed looks like Pico acting as a BLE device getting connected to some host itself if I get it right -- I didn't even try this part.

The failing example is this one https://github.com/earlephilhower/arduino-pico/blob/master/libraries/BluetoothHIDMaster/examples/KeyboardPianoBLE/KeyboardPianoBLE.ino. In particular, this loop:

arduino-pico/libraries/BluetoothHIDMaster/examples/KeyboardPianoBLE/KeyboardPianoBLE.ino

Lines 209 to 211 in 0affea4

	do {
	hid.connectBLE();
	} while (!hid.connected());

never exits on any version after 4.4.4. I've just double checked (including the latest master with your #3222 merge).

Since there are no visible changes to BluetoothHIDMaster or BluetoothHCI this code example is based on (and to your board libraries at all from what I can see), there is only this Pico SDK 2.1.0 → 2.1.2-develop update left there to blame (note though that I'm not an expert at all, I've been just playing with this microcontroller stuff for a couple of days now since I need to connect a BLE keyboard to an OS that has no Bluetooth support by making it a USB HID device with the Pico help and the USB HID part works great for me here BTW).

I'm reopening the ticket, sorry for that and feel free to create a new one if it is more suitable for you.

UPDATE. Oops, I don't have permissions to reopen -) Should I create a new ticket?

UPDATE 2. This while loop above does eventually terminate (some timeout for how long setup can run that finally kicks in and kills it?) because the BOOTSEL button starts working at some point (loop gets called) but it takes a long time and it doesn't connect even after repeated attempts to call connectBLE in response to BOOTSEL presses anyway. I should point once again that in v4.4.4 the connection is instant, on the first attempt from setup.