Re: [PATCH] usb: typec: ucsi: acpi: Check ACPI companion before use

[Huang Wei]

Hi Jiale,

A heads-up on the history here: a functionally identical patch was
posted in September by Yogesh Gaur:

  https://lore.kernel.org/linux-usb/20260920090711.300-1-yogeshgaur.83@xxxxxxxxx/

Greg declined it on the grounds that the only realistic way to reach
probe without an ACPI companion is the driver_override + sysfs bind
path, which is a deliberate root action, with the resulting OOPS
being identifiable by the taint flag - "if userspace does it, it
deserves the pieces the kernel ends up in":

  https://lore.kernel.org/linux-usb/2026092130-thong-secrecy-1dd4@gregkh/

The open question left from that thread was whether syzbot still
exercises the override+bind path - if it does and keeps generating
these reports, that would be an argument for taking the guard anyway.
Yogesh's version referenced a syzbot report; yours does not, so I
can't tell from the patch whether you hit the same report or found
this independently.

For what it's worth, the fix itself is fine - I reviewed Yogesh's
version at the time, including checking that this is the only
unchecked ACPI_COMPANION() in drivers/usb/typec/. Whether it lands
is purely a policy call at this point.

Thanks,
Huang Wei