keyboard and touchpad not working on Lenovo V15 G4 AMN

["David Lazăr" <dlazar@gmail.com>]

Hi,

The keyboard and touchpad on the Lenovo V15 G4 AMN laptop (AMD Ryzen 3 7320U) work well in the UEFI setup interface and in the bootloader, but stop working after booting the Linux kernel (Debian's 6.1.55-1). [0][1]

[0] https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-6.2/+bug/2034477
[1] https://www.reddit.com/r/archlinux/comments/13kuska/keyboard_trackpad_on_a_v15_g4_amn_not_working/

When booting, the i8042 driver prints the following message:

        i8042: PNP: PS/2 appears to have AUX port disabled, if this is incorrect please boot with i8042.nopnp

I have disassembled the DSTS ACPI table, and indeed, no mouse device seems to be declared (none of the PNP devices IDs listed in pnp_aux_devids appears, nothing using IRQ 12).  So I booted with the following kernel arguments (inspired by the i8042_dmi_quirk_table):

        i8042.debug=1 atkbd.reset=1 i8042.nomux=1 i8042.reset=1 i8042.nopnp=1 i8042.dumbkbd=1

and this is what  I got:

        i8042: PNP detection disabled
        i8042: [0] aa -> i8042 (command)
        i8042: [0] 55 <- i8042 (return)
        i8042: [0] 20 -> i8042 (command)
        i8042: [0] 67 <- i8042 (return)
        i8042: [0] 20 -> i8042 (command)
        i8042: [0] 67 <- i8042 (return)
        i8042: [0] 60 -> i8042 (command)
        i8042: [0] 76 -> i8042 (parameter)
        i8042: [0] d3 -> i8042 (command)
        i8042: [0] 5a -> i8042 (parameter)
        i8042: [0] 5a <- i8042 (return)
        i8042: [0] a7 -> i8042 (command)
        i8042: [0] 20 -> i8042 (command)
        i8042: [0] 76 <- i8042 (return)
        i8042: [0] a8 -> i8042 (command)
        i8042: [0] 20 -> i8042 (command)
        i8042: [0] 56 <- i8042 (return)
        i8042: [0] 60 -> i8042 (command)
        i8042: [1] 56 -> i8042 (parameter)
        i8042: [1] d3 -> i8042 (command)
        i8042: [1] a5 -> i8042 (parameter)
        i8042: [72]      -- i8042 (aux irq test timeout)
        i8042: [72] a5 <- i8042 (flush, aux)
        i8042: [72] 60 -> i8042 (command)
        i8042: [72] 74 -> i8042 (parameter)
        i8042: [72] 60 -> i8042 (command)
        i8042: [72] 65 -> i8042 (parameter)
        serio: i8042 KBD port at 0x60,0x64 irq 1

To my untrained eyes, this looks like a reasonable PS/2 keyboard initialization sequence, (with the AUX port seemingly unresponsive), but the keyboard still does not work.

I'm running out of ideas on what to try next, so I'd be grateful for any help.  Let me know if you need any other information I might have missed.

Thanks.