for some reason theres some issues using multiple keyboards simultaneously in linux, for some applications. this is a very small utility to merge/combine keyboards in linux into one merged input device.
mergeinputs inputeventpaths
example to merge all keyboards: mergeinputs /dev/input/by-path/*-kbd
depending on your distro you might either need the input group or run mergeinputs as root.
leveraging the uinput module, mergeinputs is able to sit before any userspace input drivers:
/dev/input/eventx /dev/input/eventy -> mergeinputs grabs all key events -> "merged input" device -> input drivers -> userspace applications
this means any application will only see one keyboard (merged inputs) pressing keys, eliminating any issues multiple devices might've caused.
make install
To start the utility on every boot, a sample systemd unit is provided:
sudo cp mergeinputs.service /etc/systemd/system
sudo systemctl enable --now mergeinputs
If you want to restart mergeinputs on device changes to handle hotplugging of keyboards, use the mergeinputs-restart units:
sudo cp mergeinputs-restart.* /etc/systemd/system
sudo systemctl enable --now mergeinputs-restart.path