I have been running a US Converters Bluetooth to serial converter with KStars/Ekos/INDI for about 2 years now. It is connected to my Robofocus system using the "rfcomm0" port set to 9600 baud. Until recently I have been able to disconnect from INDI and then reconnect without issue. When I try to reconnect now (from about KStars/Ekos version 3.1 or 3.11 forward) I get the following message in the Robofocus INDI message window:

2019-04-12T23:09:49: [WARNING] Port /dev/rfcomm0 is already used by another driver or process.
2019-04-12T23:09:36: [INFO] RoboFocus is offline.
2019-04-12T23:09:11: [INFO] Stopped.
2019-04-12T23:09:02: [INFO] Moving inward...
2019-04-12T23:09:02: [INFO] Focuser is moving to position 50
2019-04-12T23:08:48: [INFO] Stopped.
2019-04-12T23:08:48: [INFO] Moving inward...
2019-04-12T23:08:38: [INFO] Moving outward...
2019-04-12T23:08:38: [INFO] Focuser is moving to position 1000
2019-04-12T23:08:07: [INFO] Debug is enabled.
2019-04-12T23:08:06: [INFO] Device configuration applied.
2019-04-12T23:08:06: [INFO] Debug is disabled.
2019-04-12T23:08:06: [INFO] Loading device configuration...
2019-04-12T23:08:03: [INFO] Debug is enabled.
2019-04-12T23:08:02: [INFO] RoboFocus is online.
2019-04-12T23:08:01: [INFO] Auo search is disabled.

You can see that I was able to connect to the Robofocus and command a move, etc. then disconnect INDI and when I reconnect I get the error (WARNING) message.

My current system is a Raspberry RPI 3B+ setup as follows:

OS - UBUNTU Mate 16.04.6 LTS
KStars nightly PPA version 3.2 Build: 2019-04-11T11:55:34Z

I have also attached a log file. I have been running this bluetooth converter for about 2 years without problem. I have also tested a second converter (same model and type) and I have the same issue with it as well. I have tried deleting the device with the Bluetooth Manager and then reinstalling but this made no difference.

Any thoughts, ideas, help?

I have done some further testing and have found that the Bluetooth connection will release and reconnect properly when going back to the following KStars release version (not the nightly PPA) I kept on an SD card. I am using the same RPI 3 B+ and Bluetooth Dongle as in my first post.

Raspberry RPI 3B+
KStars Version 3.1
Build: 2019-01-08T12:13:33Z

Release 16.04.6 LTS (Xenial Xerus) 32-bit
Kernel Linux 4.14.89-v7+ armv7l

Is anyone else runnung a Bluetooth connection to a telescope mount, focuser, or other similar serial port connection with the latest KStars/Ekos/INDI PPA build? If so, are you experiencing a similar problem as described in my first post with disconnecting and the reconnecting from the INDI Control Panel or Ekos Module? Any feedback is appreciated.

It seems you are correct. I can no longer connect with my bluetooth adapter:
www.irxon.com/english/products/bt578_e.htm
I use it to control my iOptron CEM25C mount. I'm using a nightly version dated April 13 2019. After reverting to a stable version all is working again.

Hi Brian,

Thank you for the reply and the additional confirmation of this problem. It is also good to know that going back to a recent stable version worked for you as well.

In further testing, I tried the same test using an ASUS Tinkerboard with UBUNTU Mate 18.04.2 LTS and running KStars PPA nightly version 3.2 Build: 2019-04-14T19:19:24Z (this is an updated NAFABox build I have recently been testing for my system - thanks to the dedicated crew who made this build). The results are the same. I can make the first connection to the Bluetooth "rfcomm0" port just fine and the focuser works properly. Upon disconnecting from the Robofocus in the INDI control panel and then trying a reconnect I get the same error warning as my first post . It seems the port is not being released properly or something similar. In looking at the logs with KStars/INDI logging at verbose as attached to my first post it doesn't really show much. I hope the developers have a better way of tracking the issue. Thanks again for your reply and information.

Can you compile from source? I suspect it could be related to this change here: github.com/indilib/indi/blob/ab4933bca72.../libs/indicom.c#L980

Can you comment out this block (from line #980 to #985) and see if this resolves your BT issue?

Jasem,
I'll look at setting up a development environment over the next few days. I have initially looked at the development documentation to do this and it looks to be pretty straight forward. I run Kubuntu 18.04 on my desktop machine so I'll probably just set up the dev environment there and run the tests on that machine. I'll let you know what I find.