i8042: Fujitsu LIFEBOOK U7410 needs i8042.nomux (keyboard and touchpad dead)

Hi,

On a Fujitsu LIFEBOOK U7410 the internal keyboard and touchpad are dead
after boot with the default i8042 settings. Both work in BIOS and GRUB.
The kernel registers the devices (AT Translated Set 2 keyboard, and the
Elan touchpad 04F3:3092 via I2C-HID), but evtest shows no events on
either.

System:
  Kernel:          7.0.0-31-generic (Linux Mint 22.3)
  sys_vendor:      FUJITSU CLIENT COMPUTING LIMITED
  product_name:    LIFEBOOK U7410
  board_name:      FJNB2D4
  BIOS:            Version 2.12, 06/23/2020

With default parameters, dmesg reports:

  i8042: Detected active multiplexing controller, rev 1.1
  atkbd serio0: Spurious ACK on isa0060/serio0 (repeated)
  atkbd serio0: Unknown key pressed (translated set 2, code 0x0)

What I tried:
  - i8042.nopnp i8042.reset: no change
  - i8042.nomux=1 i8042.reset: keyboard and touchpad work, on warm and
    cold boot. The multiplexing message and the Spurious ACK messages
    no longer appear.
  (I have not tested i8042.nomux=1 without i8042.reset.)

Could a DMI quirk with nomux be added for this model?

Thanks,

Heiko
-- 
Heiko Brey

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