Comment 37 for bug 1759836

Created attachment 274593
dmesg

Hi,
I'm currently running ubuntu 18.04 with a 4.15 kernel and i can observe very high cpu usage to the systemd-udevd deamon.

removing the rule :
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"

Solved the high CPU usage eventhough my bluetooth card is not available anymore (as not in hci mode)

It seems that the command hid2hci creates a bind/unbind loop in udev that is looping trying to set the device in hci mode. (that what udevadm monitor seems to show, looping from bind to unbind for the device)

I suspect a0085f2510e8976614ad8f766b209448b385492f introduced a regression (i have not tried to revert it yet).

Please not that there also seem to be a bug in hid2hci.c from bluez l148 :
 if (err == 0) {
  err = -1;
  errno = EALREADY;
 }
Correcting this and recompile bluez desn't solve the issue as cpu usage remains very high.

Using a 4.13 kernel result in a normal CPU usage, this seems a regression in 4.14.

Other people seems to have the same issue, here is a bug report related to this :
https://dev.solus-project.com/T5224

Thanks a lot for your support,

Mathieu Tournier