How to debug DRI problems?

Hi there,

I am trying to run kodi-standalone in a docker setup (also tried direct
on host). GBM, hence DRI usage.=20
However I do not get it to output to the HDMI I have connected. Logs
are not showing anything useful to me. I had that same setup working
before and can't find the cause why nothing ends up with the screen.

Is there any way to get more information in a debug mode from the
driver to see what is happening and finding the core of this issue?

Sorry for a noob question here, but I really exhausted my options so
far.

Kind regards
  Chris