Comment # 1 on bug 1176971 from Steffen Klein

For the record, kernel tested:
# uname -a
Linux xxxxxxxxxxx 5.8.10-1-default #1 SMP Mon Sep 21 11:00:19 UTC 2020
(af3e800) x86_64 x86_64 x86_64 GNU/Linux

I adapted now the workaround provided in
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1861610/comments/66 (just
built a fixed dsdt.aml and did a acpi /boot/dsdt.aml in grub.cfg before kernel
load (had to disable secure boot in BIOS for that workaround).

I can confirm, that the touchpad works aftwerwards.

Nevertheless it would be nice to have the available kernel fix included in the
standard kernel for not having to fix with the dsdt to get a working touchpad
(and yes, I'm aware of the fact, that this is a BIOS-bug which originally
should be fixed by Lenovo...)

The steps I took:
# acpidump -b
# iasl -d dsdt.dat
# vi dsdt.dsl 
 - Search the HID of the touch pad: ELAN0634
 - Search the next _STA method declaration 
   and comment out these four lines:

  Method (_STA, 0, NotSerialized)  // _STA: Status
  {
    //If ((TPVD == 0x45))
      //{
          Return (0x0F)
      //}
      //Return (Zero)
  }

 - Increment the version number. It���s the last parameter of the DefinitionBlock
(line 21 for me):
  DefinitionBlock ("", "DSDT", 2, "LENOVO", "ICL     ", 0x20170002)

# iasl -sa dsdt.dsl
# cp dsdt.aml /boot

reboot, press e in grub menu on your linux boot entry and enter the following
line before kernel loading:
 acpi /boot/dsdt.aml
(Secure boot has to be disabled in BIOS!)

If it works, add it permanently to the grub.cfg