Re: [v3.20]: Missing /sys/class/ACAD directory OR Cannot release Mutex

From: JÃrg Otte
Date: Tue Feb 24 2015 - 08:29:41 EST


2015-02-24 12:03 GMT+01:00 JÃrg Otte <jrg.otte@xxxxxxxxx>:
> 2015-02-24 0:24 GMT+01:00 Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>:
>> On Sunday, February 22, 2015 01:33:09 PM JÃrg Otte wrote:
>>> Starting with kernel 3.19.0-05184-g18320f2, I often find my notebook
>>> running with 'powersave' policy even if it is on AC.
>>>
>>> It turned out that /sys/class/ACAD directory is missing and in the
>>> logs I see:
>>>
>>> ACPI Error: Cannot release Mutex [MUT0], not acquired (20150204/exmutex-376)
>>> ACPI Error: Method parse/execution failed [\_SB_.ACAD._PSR] (Node
>>> ffff880216028d48), AE_AML_MUTEX_NOT_ACQUIRED (20150204/psparse-536)
>>> ACPI Exception: AE_AML_MUTEX_NOT_ACQUIRED, Error reading AC Adapter
>>> state (20150204/ac-131)
>>>
>>> At the last 25 startups since 3.19.0-05184-g18320f2 it occured 13 times.
>>>
>>> It does not occur with kernels older than 3.19.0-05184-g18320f2.
>>
>> Which mainline commit is that?
> 18320f2 Merge tag 'pm+acpi-3.20-rc1-2' of
> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
>
>>
>> The only changes in 4.0-rc1 that can affect that are the ACPI EC updates IIRC.
>>
>> Is there a chance to try the acpi-ec branch from linux-pm.git and see if the
>> problem is there?
> Should be no problem. I will give it a try.

I booted kernel 3.19.0-rc5-00560-g92e4b1b from linux-pm/acpi-ec 5 times
and it didn't occure.

Today I noticed 2 other things:
1) There are at least 2 slightly different error cases
a) ACPI Error: Cannot release Mutex [MUT0], not acquired
b) ACPI Error: Thread 370114560 cannot release Mutex [MUT0]
acquired by thread ..

2) Boot times are different between good and bad case, bad case takes
significally longer:
a) Good case
[ 0.285892] intel_idle: MWAIT substates: 0x21120
[ 0.285893] intel_idle: v0.4 model 0x3A
[ 0.285894] intel_idle: lapic_timer_reliable_states 0xffffffff
[ 0.288461] ACPI: AC Adapter [ACAD] (off-line)

b) Bad case
[ 0.284061] intel_idle: MWAIT substates: 0x21120
[ 0.284062] intel_idle: v0.4 model 0x3A
[ 0.284063] intel_idle: lapic_timer_reliable_states 0xffffffff
[ 1.279089] tsc: Refined TSC clocksource calibration: 2494.334 MHz
[ 2.280355] Switched to clocksource tsc
[ 5.194933] ACPI Error: Thread 370114560 cannot release Mutex [MUT0]

Thanks, JÃrg
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