Enforce LE transport mode for dual-mode (LE/EDR) peripherals

Summary

Double mode devices (LE/EDR) can be connected in both modes in which situation Android tends to use the EDR mode. There is at least one known behaviour related—in EDR mode specific services may not be discovered correctly. As RxAndroidBle is library aiming on BLE devices the BLE mode should be forces where possible.

[dariuszseweryn]

We are using TRANSPORT_LE whenever possible and it was a deliberate decision. Earlier versions of Android did pose difficulties when TRANSPORT_BREDR or TRANSPORT_AUTO was selected. In fact this is a BLE library hence the TRANSPORT_LE

From my experience the GATT_INSUF_AUTHORIZATION should not disconnect the peripheral but only reject a characteristic write/read. I have seen disconnections (even Today in fact) with status 8 which were not connected with bonding as the peripheral did not support bonding at all (from my knowledge). So I think that this may be a misattribution.

[Drjacky]

I have seen disconnections (even Today in fact) with status 8 which were not connected with bonding as the peripheral did not support bonding at all (from my knowledge).

The peripheral which I tested does actually support bonding. We didn’t encounter this GATT_INSUF_AUTHORIZATION on other phones such as some Samsung phones & Google Pixel 2 XL. So that makes me thinking that this is a problem of the bluetooth stack included in the Android OS of the Moto G phone.

Same issue here. Only on Samsung Galaxy Note9 - Android 10.

@thuytrinh Have you found any solution for this issue?