Comment 3 for bug 1947417

I am the creator of the mentioned post at archlinux bbs. Apparently I needed to stop troubleshooting this issue (no time). I was at the stage of tracing functions in the newest kernel, but I failed. I wrote to the linux-i2c mailing list and Dmitry gave me a few hints before that.

He suspects that the BIOS update made changes to the ACPI description that Linux didn't expect.

I solved this issue for me with downgrading to the earlier BIOS version:
- Install Windows on an usb stick
- F2 at boot > Configuration > Enable Boot downgrade (or similiar)
- Boot into Windows (set it up etc.)
- Download earlier BIOS: https://download.lenovo.com/consumer/mobiles/FPCN21WW.exe
- Execute & let it Flash (TMP is reset; a warning is shown; I just ack'd it)

To help in some way, I can post my current bag of information:
https://op.xn--bimann-cta.de/bug/2021-10-15_dmesg.txt
https://op.xn--bimann-cta.de/bug/2021-10-16_trace.txt
https://op.xn--bimann-cta.de/bug/2021-10-17_dmesg.txt
https://op.xn--bimann-cta.de/bug/2021-10-17_trace.txt
https://op.xn--bimann-cta.de/bug/acpidump.lenovo-Ideapad-Flex-3-11ADA05.txt
https://op.xn--bimann-cta.de/bug/hwinfo.txt
https://op.xn--bimann-cta.de/bug/running_config.txt

Working:
https://op.xn--bimann-cta.de/bug/working_acpidump.lenovo-Ideapad-Flex-3-11ADA05.txt
https://op.xn--bimann-cta.de/bug/working_dmesg.txt
https://op.xn--bimann-cta.de/bug/working_hwinfo.txt

Also see my mailing list entry: https://<email address hidden>/
If I can be of any further assistance, feel free to ask.