Not able to Broadcast BT-PAN

Using BT-PAN we must be able to connect more than one devices. But as of now we are able to pair multiple devices, but only one device can be connected.

Could you specify which board and software/release you’re using?

I am using linaro 4.14.89 kernel and the linaro supported Debian image for dragonboard 820c.

coul you please share the way you setup BT-PAN on your system

I am using the bluez application for Bluetooth commands.
So using bluetoothctl interface was trying to connect multiple devices.
First power on the bluetooth and then make it discoverable using the commands power on and discoverable on respectively. Then paired two devices using the command pair . After that tries to connect the devices using the command connect . The first device use to connect fine, but whenever try to connect the other device it is getting the failure message “Failed to pair: org.bluez.Error.ConnectionAttemptFailed”.

The below shown is the logs which I was getting while trying to connect:-

[bluetooth]# discoverable on
Changing discoverable on succeeded
[CHG] Controller 48:5F:99:48:F8:06 Discoverable: yes
[bluetooth]# scan on
Discovery started
[CHG] Controller 48:5F:99:48:F8:06 Discovering: yes
[bluetooth]# [ 3050.511546] g_mass_storage gadget: high-speed config #1: Linux File-Backed Storage
[NEW] Device 30:52:CB:71:23:7E LAP000296
[CHG] Controller 48:5F:99:48:F8:06 Discoverable: no
[bluetooth]# [ 3223.075541] IPv6: ADDRCONF(NETDEV_UP): wlp1s0: link is not ready
[NEW] Device 18:19:D6:BB:52:66 Galaxy A50s
[bluetooth]# pair 30:52:CB:71:23:7E
Attempting to pair with 30:52:CB:71:23:7E
[CHG] Device 30:52:CB:71:23:7E Connected: yes
Request confirmation
[agent] Confirm passkey 413153 (yes/no): yes
[CHG] Device 30:52:CB:71:23:7E Modalias: bluetooth:v0006p0001d0A00
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001000-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001115-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E ServicesResolved: yes
[CHG] Device 30:52:CB:71:23:7E Paired: yes
Pairing successful
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001000-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001115-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E ServicesResolved: no
[CHG] Device 30:52:CB:71:23:7E Connected: no
[CHG] Device 30:52:CB:71:23:7E Class: 0x002a010c
[CHG] Device 30:52:CB:71:23:7E Icon: computer
[bluetooth]# trust 30:52:CB:71:23:7E
[CHG] Device 30:52:CB:71:23:7E Trusted: yes
Changing 30:52:CB:71:23:7E trust succeeded
[bluetooth]# paired-devices
Device 30:52:CB:71:23:7E LAP000296
[bluetooth]# connect 30:52:CB:71:23:7E
Attempting to connect to 30:52:CB:71:23:7E
[CHG] Device 30:52:CB:71:23:7E Connected: yes
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001000-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 0000110a-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001115-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device 30:52:CB:71:23:7E ServicesResolved: yes
Connection successful
[LAP000296]# scan on
Failed to start discovery: org.bluez.Error.InProgress
[LAP000296]# scan off
Discovery stopped
[CHG] Controller 48:5F:99:48:F8:06 Discovering: no
[CHG] Device 18:19:D6:BB:52:66 RSSI is nil
[CHG] Device 30:52:CB:71:23:7E TxPower is nil
[CHG] Device 30:52:CB:71:23:7E RSSI is nil
[LAP000296]# pair 18:19:D6:BB:52:66
Attempting to pair with 18:19:D6:BB:52:66
[CHG] Device 18:19:D6:BB:52:66 Connected: yes
Request confirmation
[agent] Confirm passkey 938819 (yes/no): yes
[LAP000296]# paired-devices
Device 30:52:CB:71:23:7E LAP000296
[CHG] Device 18:19:D6:BB:52:66 Connected: no
[CHG] Device 18:19:D6:BB:52:66 Paired: yes
Pairing successful
[CHG] Device 18:19:D6:BB:52:66 Connected: yes
[CHG] Device 18:19:D6:BB:52:66 Connected: no
[LAP000296]# connect 30:paired-devices
Device 30:52:CB:71:23:7E LAP000296
Device 18:19:D6:BB:52:66 Galaxy A50s
[LAP000296]# connect 18:19:D6:BB:52:66
Attempting to connect to 18:19:D6:BB:52:66
Failed to connect: org.bluez.Error.Failed
[LAP000296]# connect 18:19:D6:BB:52:66
Attempting to connect to 18:19:D6:BB:52:66
Failed to connect: org.bluez.Error.Failed
[LAP000296]# [ 3533.168681] Bluetooth: Unexpected continuation frame (len 54)
[ 3533.169727] Bluetooth: Unexpected continuation frame (len 6)
[ 3538.079192] IPv6: ADDRCONF(NETDEV_UP): wlp1s0: link is not ready
[ 3853.080567] IPv6: ADDRCONF(NETDEV_UP): wlp1s0: link is not ready
[ 3974.640653] g_mass_storage gadget: high-speed config #1: Linux File-Backed Storage
[LAP000296]# disconnect
Attempting to disconnect from 30:52:CB:71:23:7E
[CHG] Device 30:52:CB:71:23:7E ServicesResolved: no
Successful disconnected
[CHG] Device 30:52:CB:71:23:7E Connected: no
[bluetooth]# paired-devices
Device 30:52:CB:71:23:7E LAP000296
Device 18:19:D6:BB:52:66 Galaxy A50s
[bluetooth]# connect 18:19:D6:BB:52:66
Attempting to connect to 18:19:D6:BB:52:66
[CHG] Device 18:19:D6:BB:52:66 Connected: yes
[CHG] Device 18:19:D6:BB:52:66 Modalias: bluetooth:v0075p0100d0201
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001105-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 0000110a-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001112-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001115-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001116-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 0000111f-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 0000112d-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 0000112f-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001132-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001800-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 00001801-0000-1000-8000-00805f9b34fb
[CHG] Device 18:19:D6:BB:52:66 UUIDs: 7c7bcc5e-27a2-11e9-ab14-d663bd873d93
[CHG] Device 18:19:D6:BB:52:66 ServicesResolved: yes
Connection successful
[Galaxy A50s]# connect 30:52:CB:71:23:7E
Attempting to connect to 30:52:CB:71:23:7E
[CHG] Device 18:19:D6:BB:52:66 ServicesResolved: no
[CHG] Device 18:19:D6:BB:52:66 Connected: no
Failed to connect: org.bluez.Error.Failed
[bluetooth]# disconnect
Missing device address argument
[bluetooth]# disconnect 18:19:D6:BB:52:66
Attempting to disconnect from 18:19:D6:BB:52:66
Successful disconnected
[bluetooth]# connect 30:52:CB:71:23:7E
Attempting to connect to 30:52:CB:71:23:7E
Failed to connect: org.bluez.Error.Failed
[bluetooth]#

It is sometimes connecting for the first time after pairing the second devices. Next time onward, both the devices wont be able to connect.

Once your devices are paired, you should use the specific app you want to run depending on the profile you want to connect to. So in your case you probably wnat to use bt-pan app/tool.

http://bluez.sourceforge.net/contrib/HOWTO-PAN
https://blog.fraggod.net/2015/03/28/bluetooth-pan-network-setup-with-bluez-5x.html