Do I have to replace /lib/udev/rules.d/99-steam-perms.rules from Ubuntu's steam pkg?
Installing Steam from the Ubuntu 16.04 repositories places a file in /lib/udev/rules.d/ named 99-steam-perms.rules which has their default Steam Controller setup and contains this text:
# Steam Controller device node write access, per lp:1498655
SUBSYSTEM=="usb", ATTRS{idVendor}=="28de", ATTRS{idProduct}=="1102", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="28de", ATTRS{idProduct}=="1002", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="28de", ATTRS{idProduct}=="1142", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="28de", ATTRS{idProduct}=="1042", MODE="0666"
# Steam Controller udev write access, per lp:1498658
KERNEL=="uinput", SUBSYSTEM=="misc", TAG+="uaccess"
Seeing that the udev rules provided in the README are different (but have some similarities like the idVendor value), do I have to replace the text in the 99-steam-perms.rules file or remove it entirely to work with this driver? Or do I just leave it as is and this driver will work without further editing?
I'd say give it a try as is and see if it works. If it doesn't, you might need to add GROUP=games.
You might need to add MODE="0666" on your last rule if its not working.
My sample udev rules gives permissions only to game group ubuntu's one gives rights to everybody.