Re: RE: ACPI -- Workaround for broken DSDT

[Bas Mevissen <ml-Y9IUUvl1dgU0Iwp8Nzs06g@public.gmane.org>]

Andi Kleen wrote:

> 
> To guarantee parseable AML all you have to do is to compile the AML
> with the Intel AML compiler (available from the Intel ACPI website)
> This could be done from the source code or by just disassembling
> it (iasl -d DSDTdump) and then reassembling it. If it compiles it should be ok
> for the interpreter.
> 

That would at least mean that the interpreter would not have to deal 
with it at runtime. But it looks like a lot of DSDTs don't even pass 
that test...

How is the interpreter currently designed/behaving to cope with such 
situation?

> Of course that doesn't guarantee that Linux will work with it
> (it could parse the tables incorrectly or not like something the
> methods do when executed) but will catch at least some basic AML errors and
> do some static verifying.
> 

Maybe linux-acpi should first do a quick-scan on the DSDT and then 
decide in what "emulation-mode" it should go. Think of

* Simply good according ACPI-2.xxx spec -> follow the spec (ideal case)

* Special Linux-specific behaviour in DSDT -> do what the ACPI 
implementation of does at the moment (likely older BIOS that was tested 
on _some_ version of Linux-acpi)

* DSDT with behaviour customised for one or more Windows version -> 
emulate one of them (the latest version named?)

* Nothing -> just pick a windows emulation depending on BIOS date or 
other prior knowledge

Regards,

Bas.





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