New: scaling_max_freq locked
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: [email protected]
ReportedBy: [email protected]
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
http://bugzilla.kernel.org/show_bug.cgi?id=10982
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |acpi-
| |[email protected]
| |et
Status|NEW |NEEDINFO
Summary|scaling_max_freq locked |scaling_max_freq locked -
| |Thinkpad T42------- Comment #1 from [email protected] 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
In reply to [email protected]http://bugzilla.kernel.org/show_bug.cgi?id=10982
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |[email protected] Regression|0 |1
------- Comment #2 from [email protected] 2008-06-25 15:32 ------- I marked this as a regression.
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[Bug 10982] scaling_max_freq locked - Thinkpad T42
In reply to [email protected]http://bugzilla.kernel.org/show_bug.cgi?id=10982
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |[email protected]
------- Comment #3 from [email protected] 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
In reply to [email protected]http://bugzilla.kernel.org/show_bug.cgi?id=10982
------- Comment #4 from [email protected] 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
In reply to [email protected]http://bugzilla.kernel.org/show_bug.cgi?id=10982
[email protected] changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|[email protected] |[email protected] | |m Status|NEEDINFO |NEW Component|cpufreq |Power-Processor Product|Power Management |ACPI
------- Comment #5 from [email protected] 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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