Re: [BUG] USB-C DisplayPort Alt-Mode not detected on MSI Cyborg 15 A12VE (Alder Lake + RTX 4050)

[Francesco Orro <ncesco@interstellar.eu>]

Hi,

One of the symptoms you describe (no Type-C ports under /sys/class/typec)
matches a firmware quirk I recently ran into on an HP ZBook Fury G1i,
and posted a WIP patch for:

  https://lore.kernel.org/linux-usb/20260420172343.84456-1-ncesco@interstellar.eu/

In my case the HP "UcsiAcpi" SSDT exposes a _DSM function 2 (READ) whose
body is empty, so UCSI_VERSION stays 0x0000 and ucsi_init() bails with
-ENODEV. The patch (DMI-gated) bootstraps the PPM via _DSM func 1
(WRITE) at probe time and falls back to UCSI 1.2. After that,
/sys/class/typec/port* appears with partner alt-modes populated.

If the same firmware quirk is present on your MSI, adding its DMI match
to the quirk list in the patch should be enough to get typec ports to
show up. It won't necessarily fix the DP alt-mode negotiation by itself,
but it is a prerequisite for the typec stack to do anything.

Could you share:
1. `dmesg | grep -iE 'ucsi|USBC000'` from a fresh boot
2. The contents of your "UcsiAcpi" SSDT - run:
     sudo apt install acpica-tools
     mkdir /tmp/acpi && cd /tmp/acpi
     sudo acpidump -b
     iasl -d *.dat
     grep -lF 'UcsiAcpi' *.dsl
   and attach the matching ssdtNN.dsl
3. `cat /sys/class/dmi/id/sys_vendor /sys/class/dmi/id/product_name`

If point 2 shows an empty _DSM func 2 body similar to what I described,
we can add your laptop to the quirk list and you can test the patch
locally.

Regards,
Francesco Orro