Re: [PATCH 2/2] acpi: bus: Introduce acpi.skip_ids= boot parameter

On Thu, Aug 13, 2026 at 12:09:41PM +0200, Rafael J. Wysocki (Intel) wrote:
> On Thu, Aug 13, 2026 at 4:41 AM <[email protected]> wrote:
> >
> > From: Denis Mukhin <[email protected]>
> >
> > In virtualized environments it is possible that a device managed by the
> > hypervisor or another VM is described in the ACPI tables. In these
> > cases, binding a device driver to it can cause functional issues.
> 
> Examples, please.

One example would be a system with two MMIO-based UARTs described in ACPI
tables. Both UARTs have the same _HID, but different _UIDs. One UART reserved
for the hypervisor console, another is assigned to the guest.

Both devices reported as present and same platform driver may probe both device
instances.

I understand that, ideally, guest ACPI tables should omit the unassigned
device or report it unavailable via _STA.

The proposed parameter was intended for configurations where the device
assignment varies between boot environments while the firmware-provided ACPI
description remains common.

What would be the preferred way to prevent Linux from enumerating or probing
one specific _HID/_UID instance in such a configuration?

Thanks,
Denis