Habe da noch etwas vergessen. Vielleicht hilft es weiter.
Das XOrg Logfile beim 5.4 sieht am Ende so aus:
[ 51.771] (II) config/udev: Adding input device lircd (/dev/input/event16)
[ 51.771] (**) lircd: Applying InputClass "evdev keyboard catchall"
[ 51.771] (**) lircd: Applying InputClass "libinput keyboard catchall"
[ 51.771] (**) lircd: Applying InputClass "system-keyboard"
[ 51.771] (II) Using input driver 'libinput' for 'lircd'
[ 51.771] (**) lircd: always reports core events
[ 51.771] (**) Option "Device" "/dev/input/event16"
[ 51.771] (**) Option "_source" "server/udev"
[ 51.772] (II) input device 'lircd', /dev/input/event16 is tagged by udev as: Keyboard
[ 51.772] (II) input device 'lircd', /dev/input/event16 is a keyboard
[ 51.775] (**) Option "config_info" "udev:/sys/devices/virtual/input/input17/event16"
[ 51.775] (II) XINPUT: Adding extended input device "lircd" (type: KEYBOARD, id 15)
[ 51.775] (**) Option "xkb_layout" "de"
[ 51.776] (II) input device 'lircd', /dev/input/event16 is tagged by udev as: Keyboard
[ 51.776] (II) input device 'lircd', /dev/input/event16 is a keyboard
Beim 5.5 sört mich ein wenig event16 - lircd: device removed
[ 35.592] (II) config/udev: Adding input device lircd (/dev/input/event16)
[ 35.592] (**) lircd: Applying InputClass "evdev keyboard catchall"
[ 35.592] (**) lircd: Applying InputClass "libinput keyboard catchall"
[ 35.592] (**) lircd: Applying InputClass "system-keyboard"
[ 35.592] (II) Using input driver 'libinput' for 'lircd'
[ 35.592] (**) lircd: always reports core events
[ 35.592] (**) Option "Device" "/dev/input/event16"
[ 35.592] (**) Option "_source" "server/udev"
[ 35.594] (II) event16 - lircd: is tagged by udev as: Keyboard
[ 35.594] (II) event16 - lircd: device is a keyboard
[ 35.594] (II) event16 - lircd: device removed
[ 35.600] (**) Option "config_info" "udev:/sys/devices/virtual/input/input17/event16"
[ 35.600] (II) XINPUT: Adding extended input device "lircd" (type: KEYBOARD, id 15)
[ 35.600] (**) Option "xkb_layout" "de"
[ 35.602] (II) event16 - lircd: is tagged by udev as: Keyboard
[ 35.602] (II) event16 - lircd: device is a keyboard