Ahaaaaaa. I had my two DS3 controllers working in RetroArch using LibreELEC-Generic.x86_64-8.2-devel-20171016 following #2,063. But after an downgrade/restore to LibreELEC-Generic.x86_64-8.0-devel-20170621, and upgrade again to Generic.x86_64-8.2-devel-20171016, I'm not able to get the DS3 controllers working in RetroArch...
Tried following #2,063 again, didn't work.
But even copying the following two files from a backup of the working situation doesn't help:
/storage/.config/retroarch/retroarch.cfg
/storage/.config/retroarch/autoconfig/udev/PLAYSTATION(R)3 Controller.cfg
There is a change in controller behavior, where if I connect the DS3's with the RetroArch menu open it is continue scrolling down, and left/right of the D-pad is working. But the keyboard is not working while a controller is connected, and the other buttons don't work.
Are there other files I need to restore?
Edit:
Copied over the two files again, and now it works. It is '/storage/.config/retroarch/retroarch.cfg' that made it work.