GCW0/RG350 (OpenDingux) - Trying to make the DRM/KMS backend work

[gameblabla]

Hello,
i've been trying to make this work on the RG-350 but it always fails at

sfml-pi/src/SFML/Window/Unix/DRM/DRMContext.cpp

Line 467 in 754ed8f

if ( drmModeSetCrtc( my_drm.fd, my_drm.crtc_id, fb->fb_id, 0, 0,

with that function returning -22. "Failed to set mode: Invalid argument"
I attempted to get this working by putting

drmSetMaster(my_drm.fd);

above it but no dice sadly.

For some context, the device i'm working on has a modern linux kernel with OpenGLES 1.1/2.0 available using the open source etnaviv engine.
I was able to run other games (including with and without gl4es) on it and setting up an EGL context but usually i would do it with SDL2.
And that's confusing to me because the DRM code that you use looks very similar to the fix used for rRootage (see screen.c) :
plrguez/rRootage-for-Handhelds@96605a6

Any insight would be helpful xox
Here are the changes i've done so far :
gameblabla@b3dfc64

And the minimal sfml example project that i'm using for testing
https://github.com/gameblabla/sfml_example_drm_test