CPU going very hot when connecting ac_adapter to laptop

I noticed that when I connect the AC_Adapter to my Thinkpad X1 carbon that the fan went full-throttle and CPU temp goes up to 76C and maybe more if I let it.
Using top I saw "systemd-udevd" maxing out 2 cores.
"udevadm monitor" tells me it's bluetooth/hci connected ....
It turns out using
"sudo systemctl stop systemd-udevd systemd-udevd-kernel.socket systemd-udevd-control.socket && sudo systemctl start systemd-udevd systemd-udevd-kernel.socket systemd-udevd-control.socket"
solves the problem ... until I connect again. Then it has to be run again or I simply dont run the start bit, but then I suspect I will not have bluetooth.

Hope this helps anyone having the same problem and ,maybe it'll be gone in newer kernel releases.


Intrerestingly just using the stop command and resuming from suspend (using dpms) ..... if the touchpad is lost, using a previous solution:
"sudo modprobe -r psmouse;sudo modprobe psmouse" doesn't work. It requires a start of the sockets first. :face_with_raised_eyebrow:

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hum, this sounds like a very specific (hardware) issue :thinking: , FAQ section ?

so what is the process using this much cpu ?

It is (or was).
The laptop started having issues that it wouldn't shutdown through the OS i.e it kept booting up again spontaneously...as if the power button was stuck. :eyepopping:

If I did shutdown the machine by holding the power button for a long time, it wouldn't boot at all without the reset button (a small hole in the bottom) and the resetting time and date in the BIOS -- as if the battery had disconnected.

Eventually I opened the machine and found another (very, very small) button, similar to the reset button near one of the hinges and after pressing that (5 sec or so) --- everything was back to normal after the next reboot.
"Normal" meaning no more systemd-udevd hogging the CPU and proper shutdown procedures.:boogie: