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CPU policy & thermal problem [Solved]
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tbrass
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Joined: 14 May 2010
Posts: 15

PostPosted: Sun Apr 29, 2012 10:03 pm    Post subject: CPU policy & thermal problem [Solved] Reply with quote

Hi Forum!

I am hoping for some insight into my latest problem: I can't get my laptop's CPU to run at full speed when the battery is removed. That said, the whole reason I remove my battery is so that my laptop doesn't overheat and die (or trip a thermal sensor and shut itself down abruptly).

Neither cpufreq-set nor writing directly to /sys settings will enable me to set the freq to 2.4Ghz. But I don't see any errors in the logs or stdout. Advice would be greatly appreciated!

Here's the crux:
Code:
hal-lappy ~ # cat /sys/devices/system/cpu/cpu0/cpufreq/bios_limit
1600000

That said, windows recognizes no such limit. My cpu has no problem with 2.4Ghz when I dual boot. Moreover, when I try to write to bios_limit or scaling_max_freq or anything similar, the value doesn't change. No error, no permission problem, it just doesn't change.

Given that most of my processor-intensive activities occur in linux, I need to resolve this problem!

My system is a lenovo x200 thinkpad. The bios options are quite limited, but I have tried every CPU/energy/acpi setting and the response is always the same. without my battery, I can't go above 1.6G. With the battery, of course: no problem (other than the system getting really, really hot, before I yank it in a panic).

Any advice on how I should start investigating this would be greatly appreciated.

Thanks!

Code:
# cat /proc/cpuinfo
processor   : 0
vendor_id   : GenuineIntel
cpu family   : 6
model      : 23
model name   : Intel(R) Core(TM)2 Duo CPU     P8600  @ 2.40GHz
stepping   : 10
microcode   : 0xa0c
cpu MHz      : 800.000
cache size   : 3072 KB
physical id   : 0
siblings   : 2
core id      : 0
cpu cores   : 2
apicid      : 0
initial apicid   : 0
fpu      : yes
fpu_exception   : yes
cpuid level   : 13
wp      : yes
flags      : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts nopl aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm ida dts tpr_shadow vnmi flexpriority
bogomips   : 4788.82
clflush size   : 64
cache_alignment   : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor   : 1
vendor_id   : GenuineIntel
cpu family   : 6
model      : 23
model name   : Intel(R) Core(TM)2 Duo CPU     P8600  @ 2.40GHz
stepping   : 10
microcode   : 0xa0c
cpu MHz      : 800.000
cache size   : 3072 KB
physical id   : 0
siblings   : 2
core id      : 1
cpu cores   : 2
apicid      : 1
initial apicid   : 1
fpu      : yes
fpu_exception   : yes
cpuid level   : 13
wp      : yes
flags      : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts nopl aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm ida dts tpr_shadow vnmi flexpriority
bogomips   : 4787.74
clflush size   : 64
cache_alignment   : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

hal-lappy ~ #
hal-lappy ~ # cpufreq-set -u 2.4Ghz -c0 -r
hal-lappy ~ # cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 10.0 us.
  hardware limits: 800 MHz - 2.40 GHz
  available frequency steps: 2.40 GHz, 2.40 GHz, 1.60 GHz, 800 MHz
  available cpufreq governors: conservative, userspace, ondemand, performance
  current policy: frequency should be within 800 MHz and 1.60 GHz.
                  The governor "userspace" may decide which speed to use
                  within this range.
  current CPU frequency is 1.60 GHz (asserted by call to hardware).
  cpufreq stats: 2.40 GHz:0.00%, 2.40 GHz:0.00%, 1.60 GHz:45.78%, 800 MHz:54.22%  (5317)
analyzing CPU 1:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 0 1
  CPUs which need to have their frequency coordinated by software: 1
  maximum transition latency: 10.0 us.
  hardware limits: 800 MHz - 2.40 GHz
  available frequency steps: 2.40 GHz, 2.40 GHz, 1.60 GHz, 800 MHz
  available cpufreq governors: conservative, userspace, ondemand, performance
  current policy: frequency should be within 800 MHz and 1.60 GHz.
                  The governor "userspace" may decide which speed to use
                  within this range.
  current CPU frequency is 1.60 GHz (asserted by call to hardware).
  cpufreq stats: 2.40 GHz:0.00%, 2.40 GHz:0.00%, 1.60 GHz:47.86%, 800 MHz:52.14%  (5302)



I posted in this forum b/c I am running Funtoo (so, openrc, etc.)

update: EatMeerKats pointed out that I was looking at bad data, so I am going to just focus on the overheating problem.


Last edited by tbrass on Fri May 11, 2012 11:40 pm; edited 1 time in total
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EatMeerkats
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PostPosted: Mon Apr 30, 2012 12:47 am    Post subject: Reply with quote

You must be using the stock 65W power adapter, which doesn't let you run the CPU at full speed with the battery removed. You'll have to get a 90W adapter to do this. (Although the overheating doesn't sound right either… I used to be able to compile stuff all day with no problem on my old X201)
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tbrass
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PostPosted: Mon Apr 30, 2012 3:41 am    Post subject: Any other potential workarounds? Reply with quote

Thanks for the suggestion, EatMeerkats -- I am using the stock power adapter.

It's an older laptop (though not nearly as out of date as the Toshiba R15 from which I am currently writing), the fan is failing and the battery can no longer hold much more than 55% of its full charge. As well, I have read quite a few complaints about overheating on the x200 online, so perhaps there is something else in the design?

Is there any way to work around this 90w vs 65w setting through software? Windows clearly does, as I have no problem jumping to 2.4Ghz on both cores. And if windows can violate hardware specs, linux ought to be able to accomplish the same kludge.

Could I somehow tell udev that if it sees a 65w power adapter, it actually sees a 90w adapter? I know how to write a rule that identifies an input device as a mouse, could the same be accomplished here?
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EatMeerkats
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PostPosted: Mon Apr 30, 2012 1:39 pm    Post subject: Reply with quote

Are you 100% sure Windows is running the CPU at full speed? Something like CPU-Z will show the actual CPU speed… as far as I know, this limitation is embedded in the BIOS/embedded controller and there is no way to work around it. A little more info: http://forums.lenovo.com/t5/X-Series-ThinkPad-Laptops/ThinkPad-CPU-runs-at-reduced-maximum-clock-speed-with-no-battery/ta-p/545661
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tbrass
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PostPosted: Fri May 11, 2012 11:39 pm    Post subject: You're right! Alas. Reply with quote

EatMeerKats - you were spot on. I wasn't looking at real time clock speed data. Why I wasn't using CPU-Z is beyond me (I have probably gotten too used to linux).

So now I am stuck trying to figure out why the laptop trips a thermal sensor in windows (shutdown @ about 75C), never in linux (perhaps I haven't hit 75c?). Afterward, I can look into whether a 3rd party adapter might trick the EC into running at full load.

First step - reseating the heat sink (again) with good paste (again) on the off chance I did it wrong the first time.

Thanks for your help.
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