[BRLTTY] Repeated Bluetooth pairing request on Android

[Dave Mielke]

[quoted lines by Robert Pösel on 2018/03/05 at 18:20 +0100]

>And during writing of this e-mail I've found the issue and solution.

Excellent!

>Problem was indeed in BRLTTY code, namely in the BluetoothConnection.open() 
>method. There is check "if (channel == 0)" based on which it uses either 
>direct call on device object, or it uses reflection to call some hidden method 
>on the device object. I don't understand the purpose of this channel argument 
>and whole condition, could you clarify why it was written this way?

Some braille devices (by now, usually older ones) don't support SDP 
(Bluetooth's Service Discovery Protocol). Some drivers, therefore, supply a 
hard-coded channel number to try if SDP isn't working.

I just checked the HumanWare driver. It specifies to fall back to RFCOMM 
channel 1, and doesn't request that SDP be tried. This was the problem, and has 
now been fixed.

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