GPE handler livelock

[Nate Lawson]

Great, thanks both of you.  I'll rework this for FreeBSD and repost.

Alexey Starikovskiy wrote:
> Here is the patch...
> Alexey Starikovskiy wrote:
>> I proposed this patch some time ago, it moves _Lxx enabling to the end
>> of Notify queue, thus all notifies must complete before event becomes
>> enabled again.
>> Hope it is readable to non-Linux people...
>>
>> Regards,
>> Alex.
>>
>> Moore, Robert wrote:
>>> No changes that I know of before 20070508.
>>>
>>> You'll need to figure out why you are getting another GPE before the
>>> _Lxx method completes. There was something like this on Linux with an HP
>>> machine, perhaps Alexey can help.
>>>
>>> As I recall, there was something nasty happening where the TZ trip
>>> points had to be reset before the Notify() handler completed, but this
>>> ended up causing another GPE, etc. etc.
>>>
>>> Bob
>>>
>>>
>>>> -----Original Message-----
>>>> From: Nate Lawson [mailto:nate at root.org]
>>>> Sent: Monday, January 07, 2008 10:09 AM
>>>> To: Moore, Robert
>>>> Cc: Yousif Hassan; freebsd-acpi at FreeBSD.org
>>>> Subject: Re: GPE handler livelock
>>>>
>>>> Bob, thanks for the reply.  That's exactly what my investigation is
>>>> showing also.  It appears we're still on 20070320 so I'm not sure why
>>>> this would affect us though.  Perhaps a similar change was already
>>>> present?  In any case, we should see if an import fixes this.
>>>>
>>>> Thanks,
>>>> Nate
>>>>
>>>> Moore, Robert wrote:
>>>>> This sounds suspiciously like the changes we made to the Notify()
>>>>> handling last year. We attempted to make the notify handler run
>>>>> synchronously with the caller to Notify(), but this created more
>>>>> problems than it solved. We ended up returning the behavior of Notify
>>>>> handlers to be asynchronous:
>>>>>
>>>>>
>>>>>
>>>>> 19 October 2007. Summary of changes for version 20071019:
>>>>>
>>>>> 1) ACPI CA Core Subsystem:
>>>>>
>>>>> Reverted a change to Notify handling that was introduced in version
>>>>> 20070508. This version changed the Notify handling from asynchronous
>>> to
>>>>> fully synchronous (Device driver Notify handling with respect to the
>>>>> Notify
>>>>> ASL operator). It was found that this change caused more problems
>>> than
>>>>> it
>>>>> solved and was removed by most users.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: owner-freebsd-acpi at freebsd.org [mailto:owner-freebsd-
>>>>>> acpi at freebsd.org] On Behalf Of Yousif Hassan
>>>>>> Sent: Sunday, January 06, 2008 12:18 PM
>>>>>> To: Nate Lawson
>>>>>> Cc: freebsd-acpi at FreeBSD.org
>>>>>> Subject: Re: GPE handler livelock
>>>>>>
>>>>>> Nate wrote:
>>>>>>> Thanks for digging into this.  I reviewed this and am trying to
>>>>> figure
>>>>>>> out why the _L00 handler never completes.  It keeps getting
>>> preempted
>>>>> by
>>>>>>> the next one.  To help track this down, try removing these two
>>> lines
>>>>>>> from the _L00 method and recompile your ASL:
>>>>>>>
>>>>>>>    Acquire (\_TZ.C173, 0xFFFF)
>>>>>>>    ...
>>>>>>>    Release (\_TZ.C173)
>>>>>>>
>>>>>>> For others who have this problem, instructions on how to recompile
>>>>> and
>>>>>>> load your custom ASL can be found here (11.16.4 and 5):
>>>>>>>
>>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/acpi-debug.htm
>>>>> l
>>>>>> I'm not sure if my situation is exactly what you're referring to in
>>>>>> this note, but since my laptop is also an HP (nx6110), and since it
>>>>> also
>>>>>> hangs during thermal zone changes, I tried your suggestion.  It
>>> didn't
>>>>>> help, unfortunately.  I still get mutex problems when the thermal
>>> zone
>>>>>> increases.  My ASL did not have precisely the Acquire call you
>>> listed,
>>>>>> but it did have a similar one in method _L00 called
>>>>>> Acquire (\_TZ.C170, 0xFFFF) and Release (\_TZ.C170).  Also this pair
>>>>>> of calls was also found in one other place (further down) in the
>>> ASL.
>>>>>> I only removed the first pair in the method you instructed.
>>>>>> FWIW, here are the debug error messages when the machine hangs:
>>>>>>
>>>>>> ACPI Exception (utmutex-0376): AE_TIME, Thread 28 could not acquire
>>>>> Mutex
>>>>>> [0] [20070320]
>>>>>> ACPI Error (exutils-0180): Could not acquire AML Interpreter mutex
>>>>>> [20070320]
>>>>>> ACPI Error (utmutex-0421): Mutex [0] is not acquired, cannot release
>>>>>> [20070320]
>>>>>> ACPI Error (exutils-0250): Could not release AML Interpreter mutex
>>>>>> [20070320]
>>>>>> ACPI Exception (utmutex-0376): AE_TIME, Thread 28 could not acquire
>>>>> Mutex
>>>>>> [0] [20070320]
>>>>>> ACPI Error (exutils-0180): Could not acquire AML Interpreter mutex
>>>>>> [20070320]
>>>>>> ACPI Error (psparse-0626): Method parse/execution failed
>>> [\_TZ_.C242]
>>>>> (Node
>>>>>> 0xc321c220), AE_TIME
>>>>>> ACPI Error (psparse-0626): Method parse/execution failed
>>>>> [\_TZ_.TZ1_._TMP]
>>>>>> (Node 0xc321b9c0), AE_TIME
>>>>>> ... etc ...
>>>>>>
>>>>>> I put more info into PR 79080.
>>>>>>
>>>>>> Let me know if you want me to try anything else.
>>>>>> --Yousif
>>>>>>
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>>>> -- 
>>>> Nate
>>
>>
> 

-- 
Nate