Created attachment 682777 [details]
The current (from upstream) libcec udev rule does not work due to two issues;
1) The rule needs to be suffixed with ".rules" not ".udev" to be considered by udev. I presume on Debian their toolset renames it on install.
2) The default 50-udev-default.rules would still take earlier precedence over a fixed 65-pulse-eight-usb-cec.rules by matching against the ttyACM0 device.
Fix both by renaming the file. However, since 50-udev-default.rules no longer applies, we can also set the group to "video" instead of "uucp" since most users are likely to be running Kodi and will already be members of the video group. (Using sed to append the group rule only on lines rules with Pulse USB vendor ID 2548.)
Same patch applies to libcec-4.0.7 (uncleanly due to whitespace change at "if use udev" line).
Created attachment 684040 [details]
Obviously didn't test properly as not working on reboot.
Need to match plural SUBSYSTEMS=="usb" not SUBSYSTEM=="usb" for child tty device. Also (mis)understood that udev would stop at first lexical rule match but 45 was being overruled by 50 for group setting so leave as original 65.
Now properly tested with unplug/plug.