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Re: [PATCH] ACPICA: Export mutex functions

From Guenter Roeck <linux@roeck-us.net>
Newsgroups linux.kernel
Subject Re: [PATCH] ACPICA: Export mutex functions
Date 2017-04-17 21:50 +0200
Message-ID <txkOR-4K8-3@gated-at.bofh.it> (permalink)
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On Mon, Apr 17, 2017 at 07:27:37PM +0000, Moore, Robert wrote:
> 
> > -----Original Message-----
> > From: Moore, Robert
> > Sent: Monday, April 17, 2017 10:13 AM
> > To: Guenter Roeck <linux@roeck-us.net>; Zheng, Lv <lv.zheng@intel.com>
> > Cc: Wysocki, Rafael J <rafael.j.wysocki@intel.com>; Len Brown
> > <lenb@kernel.org>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> > kernel@vger.kernel.org
> > 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.
> 
From the context in the dsdt, and from description of expected use cases for
_DLM objects I can find, this is what the mutex is used for (to serialize
access to a resource on a low pin count serial interconnect, aka LPC).

What does that mean in practice ? That I am not supposed to use it because
it doesn't follow standard ACPI mutex declaration rules ?

Thanks,
Guenter

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

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Thread

[PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-12 17:20 +0200
  RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-12 17:40 +0200
    Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-12 23:30 +0200
      RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-13 00:00 +0200
        Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-13 03:00 +0200
        Re: [PATCH] ACPICA: Export mutex functions "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-04-15 00:40 +0200
          RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-15 01:40 +0200
      RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-17 11:40 +0200
        RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-17 11:50 +0200
          Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-17 16:10 +0200
            RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 01:40 +0200
        Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-17 18:00 +0200
          RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-17 19:20 +0200
            RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-17 21:30 +0200
              Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-17 21:50 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-17 22:50 +0200
                Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-17 23:10 +0200
                Re: [PATCH] ACPICA: Export mutex functions "Rafael J. Wysocki" <rafael@kernel.org> - 2017-04-17 23:30 +0200
                Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-18 00:40 +0200
                Re: [PATCH] ACPICA: Export mutex functions "Rafael J. Wysocki" <rafael@kernel.org> - 2017-04-18 01:00 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 02:00 +0200
                Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-18 06:40 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 09:10 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 09:20 +0200
                Re: [PATCH] ACPICA: Export mutex functions Guenter Roeck <linux@roeck-us.net> - 2017-04-18 16:00 +0200
                Re: [PATCH] ACPICA: Export mutex functions "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-04-18 16:30 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-18 18:10 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-19 03:30 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-19 03:40 +0200
                RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 02:00 +0200
              RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 01:50 +0200
            RE: [PATCH] ACPICA: Export mutex functions "Moore, Robert" <robert.moore@intel.com> - 2017-04-17 21:40 +0200
          RE: [PATCH] ACPICA: Export mutex functions "Zheng, Lv" <lv.zheng@intel.com> - 2017-04-18 01:40 +0200

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