Created attachment 642376 [details] Debug output from "systemd-udevd" for a connection with the model "Stylus C84" (In reply to Johannes Meixner from comment #28) I extended some debug log messages a bit in the source files which correspond to the last commit "e4e66993951e9e349e8008fa7c81184b6e4ae385" at the moment. I hope that an excerpt from the shown program control flow (for a C84 connection) is useful to achieve a better understanding here.