Instructions which are working for me here:

https://retropie.org.uk/forum/post/293697

https://www.raspberrypi.com/news/bookworm-the-new-version-of-raspberry-pi-os/

Bookworm PiOS came out in October

@PittStone
Are you running plex as a server or media player?

If you just want it to run as a server you don't need a desktop environment for that.

@bholland
Did you use the 64 bit version or the 32 bit?

You may have posted to the wrong forum - RetroPie is a retro-gaming oriented distribution, based on Raspberry Pi OS (and for the moment it's not supported on the RPI OS 'bullseye' release).

If your PS3 controller is already working, then probably you'd have to look into how the program used to read the inputs from it works with your telescope controls (connected via GPIO perhaps?). It may be that it's no longer functioning with 'bullseye' for various reasons, but without details on how this program works, it's just a guessing game trying to diagnose the issue.

@Darksavior I wouldn't recommend anyone use that branch as it was just for my own testing. Some of the commits there may be included but probably not all (and may have further changes).

@Darksavior
Also I have experimented a problem about gpu_mem, when you set it to 256 (which i don't really think is reasonable for pi zero 2, but I have tried) then emulationstation is not loading, instead it is in a constant 104% cpu using state.

I've now managed to get this working with the standard Retropie 4.8 image on a Raspberry Pi 4b!

OP updated with the new instructions!

The full process is quite some work and not tested together with other emulators. Updates to Mesa, SDL and FFmpeg are neccessary for Retropie 4.8.

@mitu Will do just that, thanks

@tavuntu Sorry, no. After I set up my controllers with ES I switch to the pegasus-frontend with my custom theme.

@mitu

I'm totally happy to do some extra installing/building if that would help.
If I build SDL2 from source repo, would I be able to fix this up without too much editing of cmake files etc?
(i do need to use Bullseye unfortunately)

EDIT:
if I did this for the SDL2 build?

./configure --enable-video-kmsdrm --enable-video-opengles

I think long term, it's much better for Raspberry Pis to have a) an open source graphics stack, and b) a more 'standard' solution. as an educational tool it seems silly for the pi having bespoke APIs, and it meant that (as above) several pieces of software ended up being tied to that bespoke ecosystem out of convenience/necessity.

@eusi said in Bullseye dist-upgrade?:

Any idea when retropie will release its new version that is based on Bullseye? Just roughly (within next some weeks?)...

No idea.