Hi I finally found the solution for my problem, so I explain it in case someone else needs it:
It’s a probleme with udev configuration, the new device manager used by SDL2.
To make my joystick work, I had to setup rights for my user + add the INPUT_ID_JOYSTICK tag on it to be recognized as the Joystick.
I created the following file:
/etc/udev/rules.d/99-joystick.rules
with this content:
# My Joystick
KERNEL==”event*”, ENV{ID_MODEL}==”USB_JOYSTICK_PS3″, MODE=”0644″, ENV{ID_INPUT_JOYSTICK}=”1″
More infos on:
https://hg.libsdl.org/SDL/file/e3e00f8e6b91/README-linux.txt