Cannot run two instances of Godot on Linux Debian

[sabudum]

Godot version

3.5.2 stable

System information

Linux Peppermint Debian

Issue description

Cannot run two or more instances of anything Godot related, be it an exported build ,the editor, or whatever.
Can't run the editor and a build.
Can't run two editors.
Can't run two builds.
Same as above with the Windows version via Wine.
Even with empty projects, without any script or resource.

Steps to reproduce

Start Linux Peppermint Debian.
Run two Godot instances.

The second instance will freeze and wait for the first to be terminated.

Minimal reproduction project

N/A

[sabudum]

Alright, just found a fix, turns out the problem lies in the nouveau nvidia driver, for some reason it blocks the execution of multiple OpenGL applications with some specific configuration, I don't know exactly why.

The solution was to completely remove the driver and install proprietary legacy nvidia drivers version 340.108 specifically, with a patch for newer linux kernels.

My graphics card is a Nvidia Geforce 9500 GT

I had no clue this was related to graphics drivers though. Maybe this sheds some light on the real problem for a permanent fix, on the nouveau drivers, that is.

[Calinou]

This is a Nouveau issue, and isn't something we can fix on our end (especially since very few contributors, if any, use Nouveau). Nouveau is the fruit of reverse engineering and is prone to regressions.

Also, are you using GLES3 or GLES2 in the project? GLES3 backend support on GeForce 8/9 series hardware is often broken, since these cards' OpenGL 3.3 support has many bugs (even with the proprietary driver).