[Bug 10982] New: scaling_max_freq locked

[Bug 10982] New: scaling_max_freq locked

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10982

           Summary: scaling_max_freq locked
           Product: Power Management
           Version: 2.5
     KernelVersion: 2.6.25
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: cpufreq
        AssignedTo: cpufreq@www.linux.org.uk
        ReportedBy: nicolas.vinot@gmail.com


Distribution: Debian testing
Hardware Environment: IBM Thinkpad T42
Software Environment: 2.6.25 kernel
Problem Description:

Few minutes after boot, scaling_max_freq is locked to the lowest cpu speed.
Impossible to change it, even by hand or cpufreq-set.

root:cpufreq# pwd
/sys/devices/system/cpu/cpu0/cpufreq

root:cpufreq# cat scaling_driver
acpi-cpufreq

root:cpufreq# cat scaling_available_frequencies
1800000 1600000 1400000 1200000 1000000 800000 600000

root:cpufreq# cat scaling_available_governors
powersave userspace ondemand conservative performance

root:cpufreq# cat scaling_governor
ondemand

root:cpufreq# cat scaling_max_freq
600000

root:cpufreq# echo 1800000 > scaling_max_freq
root:cpufreq# cat scaling_max_freq
600000

root:cpufreq# cat cpuinfo_max_freq
1800000
root:cpufreq# cat cpuinfo_max_freq > scaling_max_freq
root:cpufreq# cat scaling_max_freq
600000

root:cpufreq# cpufreq-set -u 1800000
root:cpufreq# cat scaling_max_freq
600000

Before value locking, cpufreq works perfectly as it should.

This problem often occurs when the processor heats (high load, compilation...)
but randomly too (few minutes after boot, even if it does nothing).
Sometimes, after cpu cooling or cpufreqd reboot, I can manage again the speed
by hand.

My old kernel version (2.6.18 with speedstep-centrino driver) hasn't this
problem and cpufreqd works perfectly on it.


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[Bug 10982] scaling_max_freq locked - Thinkpad T42

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10982


len.brown@intel.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |acpi-
                   |                            |bugzilla@lists.sourceforge.n
                   |                            |et
             Status|NEW                         |NEEDINFO
            Summary|scaling_max_freq locked     |scaling_max_freq locked -
                   |                            |Thinkpad T42




------- Comment #1 from len.brown@intel.com  2008-06-25 15:25 -------
Please boot with processor.ignore_ppc=1
or
# echo 1 > /sys/module/processor/parameters/ignore_ppc 

and report if scaling_max_freq stops changing.


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[Bug 10982] scaling_max_freq locked - Thinkpad T42

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10982


akpm@osdl.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |akpm@osdl.org
         Regression|0                           |1




------- Comment #2 from akpm@osdl.org  2008-06-25 15:32 -------
I marked this as a regression.


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[Bug 10982] scaling_max_freq locked - Thinkpad T42

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10982


trenn@suse.de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trenn@suse.de




------- Comment #3 from trenn@suse.de  2008-06-26 04:37 -------
The T61 where this has been reported recently on the cpufreq list did always
show a _PPC value of 0 which is correct. If ignore_ppc=1 still helps it could
also be some more complex kernel/cpufreq and not a BIOS/_PPC problem.

Can you reproduce this easily (e.g. always after some short time or trigger
it)? The report on the T61 was that it only happens on some boots, which makes
it very hard to debug it there or to verify whether a patch/change helps or
not.

If this is ACPI thermal related and is a regression it might be this one:
commit d9460fd227ed2ce52941b6a12ad4de05c195f6aa
Date:   Thu Jan 17 15:51:23 2008 +0800
    ACPI: register ACPI Processor as generic thermal cooling device

If you can reproduce the problem easily, uou may want to give it a try and test
with and without that patch (go back the git history if it doesn't patch
anymore). git-bisect is also an option then (if easy to reproduce) if it is
something else.


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[Bug 10982] scaling_max_freq locked - Thinkpad T42

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=10982





------- Comment #4 from nicolas.vinot@gmail.com  2008-06-26 05:30 -------
With ignore_ppc=1, no problem at all since my last boot.

But this problem occures very randomly and in very differente cases (with hot
or cold cpu, on heavy load or not, at the launch of screensaver...).

So, not sure for the moment the problem is completely resolved with
ignore_ppc=1, but in good way.


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[Bug 10982] scaling_max_freq locked - Thinkpad T42

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http://bugzilla.kernel.org/show_bug.cgi?id=10982


len.brown@intel.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|cpufreq@www.linux.org.uk    |venkatesh.pallipadi@intel.co
                   |                            |m
             Status|NEEDINFO                    |NEW
          Component|cpufreq                     |Power-Processor
            Product|Power Management            |ACPI




------- Comment #5 from len.brown@intel.com  2008-06-27 11:43 -------
since it (seems) PPC related, moving to ACPI category...

re: comment #3, good idea Thomas.
Nicolas, does the problem also go away with CONFIG_ACPI_THERMAL=n?


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