On my Samsung Chromebook XE303C12, Xorg segfaults when module libglamoregl.so is loaded, preventing LightDM from coming up. Dowgrading mesa fixes it. (Thanks Arch linux bbs users with DisplayLink devices from 2016!)
$this->bbcode_second_pass_code('', '
sudo pacman -U /var/cache/pacman/pkg/mesa-21.0.3-2-armv7h.pkg.tar.gz
')