Re: [Xen-devel] [GIT PULL] xen: features and fixes for 4.8-rc0

[Andrew Cooper]

On 27/07/16 19:42, Linus Torvalds wrote:
> On Wed, Jul 27, 2016 at 6:45 AM, David Vrabel <dvrabel@xxxxxxxxxx> wrote:
>> Shannon Zhao (16):
>>       Xen: ACPI: Hide UART used by Xen
> So this caused a trivial conflict. No biggie, it wasn't bad and the
> patch was acked by Rafael. However, looking at it made me somewhat
> unhappy.
>
> Should the device entry in ACPI really be hidden unconditionally? In
> particular, if we are *not* running under virtualization, it sounds
> wrong to hide it.
>
> Comments? Am I missing something?

The purpose of the ACPI STAO table (Status Override table, ratified in
ACPI 6.0) is to list items elsewhere in the ACPI namespace which should
be completely ignored.  It is used in cases where it is impossible or
prohibitive to edit the system AML.

The patch itself only hides the UART if instructed to do so by the STAO
table (last hunk).

~Andrew