BLE connection failed with REASON_TIMEOUT(10)

[Hu-Muran]

Dear developers,

When using this library, we occasionally encounter the REASON_TIMEOUT issue, which causes connection failures and leads to user complaints. Could you please explain the specific cause of this problem? Is it related to the Bluetooth function of the Android system? When REASON_TIMEOUT occurs, is the Bluetooth disconnection triggered by the App?

09-19 13:04:39.822 D [Nordic] VMStack (BCManagerHandlerThread) [Callback] Connection state changed with status: 0 and new state: 0 (DISCONNECTED) - device = [address = 4E:9F:93:04:xx:xx, name = null, uuids = null]
09-19 13:04:39.833 D [Nordic] VMStack (BCManagerHandlerThread) Disconnected - device = [address = 4E:9F:93:04:xx:xx, name = null, uuids = null]
09-19 13:04:39.843 D [Nordic] VMStack (BCManagerHandlerThread) gatt.close() - device = [address = 4E:9F:93:04:xx:xx, name = null, uuids = null]
09-19 13:04:39.869 I [XXX] BluetoothClient (BCManagerHandlerThread) connectionObserver.onDeviceDisconnected(): device = [address = 4E:9F:93:04:xx:xx, name = null, uuids = null], reason = REASON_TIMEOUT(10)

[philips77]

Hi,
Seems like the REASON_TIMEOUT is thrown here:
https://github.com/NordicSemiconductor/Android-BLE-Library/blob/565d0e136dbda772466626954ca4155cc16543ba/ble/src/main/java/no/nordicsemi/android/ble/BleManagerHandler.java#L2321

This occurs when the device disconnects without the user calling disconnect(). Some devices report status=8 (timeout), but some 0 (success):
https://github.com/NordicSemiconductor/Android-BLE-Library/blob/565d0e136dbda772466626954ca4155cc16543ba/ble/src/main/java/no/nordicsemi/android/ble/BleManagerHandler.java#L3038-L3042

Anyway, only based on your attached logs I would say, that the link terminates for some reason (out of range? phone's issue? device restarts?) and this is reported to the app (library) as disconnection with status 0.

[Hu-Muran]

Hi philips, thank you very much for your quick response.

So we cannot identify the exact cause of the Bluetooth disconnection. At the very least, the disconnection is not triggered at the App or SDK level. Does that make sense?