Comment 82 for bug 1759836

I fix the problem with this approach:

https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1759836/comments/70

from "Florian Dittmer (fd81)"

"
Following the instructions mentioned by one user in the comments helped me to solve the cpu load issue with udev-239 and kernel 4.18.17, while Bluetooth still works.

Run the following command:

/lib/systemd/systemd-udevd -D

This should print garbage in endless loop containing ".../97-hid2hci.rules:"

If so, edit /lib/udev/rules.d/97-hid2hci.rules

and add

ACTION=="add",

in front of line mentioned by above command.

In my case, I had to change the following lines in 97-hid2hci.rules from:

ATTR{bInterfaceClass}=="03", ATTR{bInterfaceSubClass}=="01", ATTR{bInterfaceProtocol}=="02", \
  ATTRS{bDeviceClass}=="00", ATTRS{idVendor}=="413c", ATTRS{bmAttributes}=="e0", \
  RUN+="hid2hci --method=dell --devpath=%p", ENV{HID2HCI_SWITCH}="1"

to:

ACTION=="add", ATTR{bInterfaceClass}=="03", ATTR{bInterfaceSubClass}=="01", ATTR{bInterfaceProtocol}=="02", \
  ATTRS{bDeviceClass}=="00", ATTRS{idVendor}=="413c", ATTRS{bmAttributes}=="e0", \
  RUN+="hid2hci --method=dell --devpath=%p", ENV{HID2HCI_SWITCH}="1"

And this fixed the issue (after reboot).
"

from