when there is a new kernel-update by update-manager, then simply
after reboot - with ubuntu-package manager uninstall nvidia-drivers (and bumblebee) - then
install nvidia-drivers again.
this looks inconvenient, but its easier ?!
The solution was found here: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1894017
I just blacklisted intel_vbtn kernel module in /etc/modprobe.d/blacklist.conf and rebooted. Author mentioned that somehow intel_vbtn thinks my laptop is in tablet mode (WHAT?!) and disabled keyboard/touchpad.
How to blacklist
To implement this, you can either create a new file in /etc/modprobe.d with the suffix .conf or use the main blacklist.conf file. The former may be preferable, since you can then just delete the file when it is no longer required (i.e. when the bug is fixed):
sudoedit /etc/modprobe.d/blacklist-intel_vbtn.conf
Add a line to the file, optionally with a comment explaining why you are doing this
# bug in module breaks keyboard, so don't load it
blacklist intel_vbtn
Save the file, exit and reboot.
P.S. After mailing with Mr. Hans de Goede from RedHat I got following answer:
This should be fixed by this upstream commit, which landed in Linus'
tree a couple of hours ago:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/platform/x86?id=8169bd3e6e193497cab781acddcff8fde5d0c416
Igor, if you do:
cat /sys/class/dmi/id/chassis_type
On your laptop, and the output is NOT "31" or "32" then this fix
should work for you.
If the output actually is "31" or "32 (which I do not expect), then
please let me know, because then we need a different fix.
P.P.S. On my system (Intel Celeron N2940) chassis_type returns 10
Best Answer
There is a bug already https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1894017
As of 6/9/2020 it has been confirmed but it is unassigned.
A possible workaround is Ctrl+Alt+F3 on a external keyboard.