RPI Graphical Session Documentation incomplete

[Johnnynator]

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The rpi doc are mentioning to use mesa-dri + xorg modesetting, but does not mention that it is needed to enable dtoverlay=vc4-kms-v3d in /boot/config.txt, which is needed at least on an rpi3.

xorg will just print that no display is found without this option.

https://docs.voidlinux.org/installation/guides/arm-devices/platforms.html?highlight=pi#graphical-session