RE: [PATCH] ACPICA: Export mutex functions

[Moore, Robert]

> -----Original Message-----
> From: Moore, Robert
> Sent: Monday, April 17, 2017 10:13 AM
> To: Guenter Roeck <linux@xxxxxxxxxxxx>; Zheng, Lv <lv.zheng@xxxxxxxxx>
> Cc: Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx>; Len Brown
> <lenb@xxxxxxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: RE: [PATCH] ACPICA: Export mutex functions
> 
> There is a model for the drivers to directly acquire an AML mutex
> object. That is why the acquire/release public interfaces were added to
> ACPICA.
> 
> I forget all of the details, but the model was developed with MS and
> others during the ACPI 6.0 timeframe.
> 
> 
[Moore, Robert] 


Here is the case where the OS may need to directly acquire an AML mutex:

>From the ACPI spec:

19.6.2 Acquire (Acquire a Mutex)

Note: For Mutex objects referenced by a _DLM object, the host OS may also contend for ownership.




Other than this case, the OS/drivers should never need to directly acquire an AML mutex.
Bob