Re: [Qemu-devel] [PATCH v3 3/4] acpi: build TPM Physical Presence interface

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 21 Jun 2018 16:13:32 +0200
Marc-André Lureau <marcandre.lureau@gmail.com> wrote:

> Hi
> 
> On Thu, Jun 21, 2018 at 3:22 PM, Marc-André Lureau
> <marcandre.lureau@gmail.com> wrote:
> > Hi
> >
> > On Thu, Jun 21, 2018 at 3:21 PM, Marc-André Lureau
> > <marcandre.lureau@gmail.com> wrote:
> >  
> >>>> +    method = aml_method("TPFN", 1, AML_SERIALIZED);  
> >>> not quite sure how this method (supposed to ) work(s),
> >>> it could use nice comment explaining mechanics.
> >>>  
> >>
> >> Windows doesn't like DerefOf (FUNC [N]), it returned wrong values. It
> >> took me a while to figure this out. My laptop TPM ACPI table uses the
> >> same trick, so I assume this is a Windows acpi bug/limitation. Instead
> >> we use a function that returns the corresponding field.  
> >
> > Sorry, I am wrong, my laptop doesn't use such table. I don't know
> > where I saw someone using the same trick though..  
> 
> fwiw, I also asked on OSR list for help but got no answer:
> http://www.osronline.com/showThread.CFM?link=288617
it is/might be fine if there is a workaround to make Windows work,
we should mention it in comment though (including windows versions
where it doesn't work) so in future someone else (including me and you)
won't break it by accident.

> 
> 
> 
> 
>