[BRLTTY] Brlapi not connecting in headless mode

[Julian Dreykorn]

Dear developers,

I've been making use of Brlapi to involve a braille display in an 
existing program that is running on a Raspberry Pi 4b.
On initial testing I started a console program from Raspians desktop 
environment and I had no issues writing on
and reading from the braille display.

Now the Pi is set to headless again and Brlapi behaves weirdly. From my 
own logging I can confirm that the program
successfully connects to the Brlapi-server ( I get the device model etc. 
back aswell ) and enters tty-mode .
No warnings or errors are thrown. Any call to write is returned 
successfully.
Read-related functions never get called after a display key is pressed.

The device is never actually claimed though. The display is either 
constantly displaying "Screen not in text mode",
which is expected before brlapi takes control, or, if attached before 
start up, is on the login screen.
The mentioned program is started by the same user in any case, headless 
or not, automatically after powering up.
I do not expect any permission problem.

It seems to me, that the program gets handed some virtual display while 
the real displays stays completely unaffected.
I've been bug hunting to the best of my ability without any success.

If important, I am using the Java bindings.

Any insight on why this behavior happens would be very appreciated.

Best, Julian