e-mail exchange on the subject.

On 2014-03-08 16:59, Guenter Roeck wrote:
> On 03/08/2014 03:08 AM, Jean Delvare wrote:
>> On Fri, 7 Mar 2014 14:52:30 -0800, Guenter Roeck wrote:
>>> On Fri, Mar 07, 2014 at 11:04:29PM +0100, Manuel Krause wrote:
>>>> Hi, and thanks for the quick response!
>>>> No special fancy "fan control policy". 'fancontrol' isn't up or
>>>> running.
>>>> Vanilla kernels 3.11.* and 3.12.* had been working on here
>>>> without
>>>> any extra work.
>>>> -- 
>>>> # sensors
>>>> acpitz-virtual-0
>>>> Adapter: Virtual device
>>>> temp1:        +71.0°C  (crit = +256.0°C)
>>>> temp2:        +69.0°C  (crit = +110.0°C)
>>>> temp3:        +52.0°C  (crit = +105.0°C)
>>>> temp4:        +25.0°C  (crit = +110.0°C)
>>>> temp5:        +58.0°C  (crit = +110.0°C)
>>>>
>>>> coretemp-isa-0000
>>>> Adapter: ISA adapter
>>>> Core 0:       +62.0°C  (high = +105.0°C, crit = +105.0°C)
>>>> Core 1:       +60.0°C  (high = +105.0°C, crit = +105.0°C)
>>>> -- 
>>>> My notebook (HP/Compaq 6730b) does not have a seperate fan
>>>> sensor.
>>>> This is with 3.12.13 with my normal workload.
>>>>
>>>> Please, trust my above mentionned values of 94 °C vs. 74°C as I
>>>> don't like to boot 3.13.6 anymore, to avoid harm to the
>>>> notebook's
>>>> casing.
>>>
>>> Understood. Unfortunately, we'll need to get information
>>> from the new kernel to be able to track down the problem.
>>
>> Indeed. Not only the run-time temperatures, but also the high
>> and crit
>> limits.
>>
>>>> But I'd do to test any improvement-patch.
>>>
>>> So far I have no idea what is going on. I don't see anything
>>> in the
>>> drivers providing above data that would explain the behavior,
>>> but I might be missing something.
>>
>> Looks like a regression in the acpi subsystem or in power
>> management,
>> not hwmon. Hwmon is merely reporting the temperatures, it's not
>> responsible for the actual temperatures.
>>
>
> I would agree. I don't think we have enough information to be sure,
> though. There might be some unintended interaction or interference.
>
> gpu is a good hint ... for example, look at commit b9ed919f1c8
> (drm/nouveau/drm/pm: remove everything except the hwmon interfaces
> to THERM). nouveau does export pwm and fan control information,
> so any change in that code may have unintended side effects.
> Similar, I don't know how ec39f64bba (drm/radeon/dpm: Convert to
> use devm_hwmon_register_with_groups) could have the observed impact,
> as it is purely passive, but I prefer to be rather safe than sorry.
>
> This problem has now been submitted into bugzilla as
> https://bugzilla.kernel.org/show_bug.cgi?id=71711.
>
> Guenter
>

Sorry, for beeing late, had to search for/accumulate much info for you...
I hope, you like me to put it into one answer to you all CCing you.

My GFX is a GM45 Intel (mobile), shared memory, running the opensource Mesa drivers/extensions.
kernel-module: i915

According to the output of 'cpupower': I have
CPUidle driver: acpi_idle
CPUidle governor: menu

CPUfreq:
  driver: acpi-cpufreq
  available cpufreq governors: ondemand, performance
-
And "ondemand" is running.
-- 

# sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:        +41.0°C  (crit = +256.0°C)
temp2:        +92.0°C  (crit = +110.0°C)
temp3:        +71.0°C  (crit = +105.0°C)
temp4:        +26.5°C  (crit = +110.0°C)
temp5:        +25.0°C  (crit = +110.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Core 0:       +86.0°C  (high = +105.0°C, crit = +105.0°C)
Core 1:       +84.0°C  (high = +105.0°C, crit = +105.0°C)

FROM a critical "smelly" situation today, kernel-compilation, fan @100%.
-- 

Additional findings:

Identification from bootup ACPI initialisation vs. sensors:
temp1 = DTSZ
temp2 = CPUZ --> triggering Cooling in 3.12.13 if > 74°C
temp3 = SKNZ
temp4 = BATZ "Battery Zone" always calm ~ +6°C of ambient T
temp5 = FDTZ --- in 3.12.13 a representation of the cooling-fan (25 - 45 - 58 - max?)
Core 0 & Core 1 are the internal CPU T sensors.

With the 3.13.x (.5+) kernels the first gatherered cooling settings from bootup do stay forever. Means, rebooting a hot system will get a FDTZ @45°C+ and won't make any problems, as it does cool enough (even for kernel compiling on here). If it gets 25°C @bootup the system goes into emergency cooling somewhen. Same is with a suspend/resume.

Kernel 3.12.13 adjusts the cooling on it's own, but appropriately.


Thank you all for your engagement, best regards,
Manuel Krause.