Ubuntu 22.04, Fujitsu Lifebook E5510, Keyboard not working after Update. (Kernel 6.2.0-26-generic)

Summarize the problem:
after an minor Update (Ubuntu 22.04), internal keyboard not working for login. (Kernel 6.2.0-26-generic)

Provide details and any research:
First Check: goto Bios, Keyboard Working there, keyboard hardware probably ok. On Installing Ubuntu for first time on e5510 (ubuntu 20.04) i had problems with the touchpad which i solved, but this is actually working.

When appropriate, describe what you’ve tried:
I tried booting an older Kernel, with 5.19.0-50 everything works fine.

I tried modprobe i2c_hid and modprobe i2c_hid_acpi but it does not help.

I used dmesg | grep ... searching for hid, input, key and i2c to locate interesting parts, but everything is about touchpad and mouse, barely an entry found which hints directly to keyboard, they look similar.

### kernel 6.2.0-26
[    0.734497] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input2
[    4.666515] input: Fujitsu FUJ02E3 as /devices/LNXSYSTM:00/LNXSYBUS:00/FUJ02E3:00/input/input17
### kernel 5.19.0-50
[    1.376799] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input2
[    4.570803] input: Fujitsu FUJ02E3 as /devices/LNXSYSTM:00/LNXSYBUS:00/FUJ02E3:00/input/input17

any ideas are appreciated

I'm having the same issue with kernel 5.15.0-82-generic (I'm on 22.04 LTS). After some research I've found out, that the laptop switched to tablet mode. You can check if that's the case with

cat /sys/class/dmi/id/chassis_type

If the output is 10, then that's the case. A small inconvenient workaround is to close the lid and open it again (doesn't work with disk encryption). I've yet to find a permanent fix.