Issues with ondemand governor on overclocked CPU

Issues with ondemand governor on overclocked CPU

[Daniel Klaffenbach]

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Hi,

I am using a Core2 Quad (Q9650) on a Gigabyte GA-EP45-DS4 board. The default 
CPU specs look like this:
  * FSB: 333MHz,
  * Multiplier: 6-9
 
without overclocking frequency scaling with acpi-cpufreq works pretty well - 
it either uses a 6x multiplier (2 GHz) or a 9x multiplier (3 GHz).
 
After setting the FSB to 400MHz and limiting the multiplier to 6-8 in the BIOS 
(3,2 GHz), frequency scaling with the ondemand governor does not work any 
more. The actual frequency information is still correct:

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 
3200000 2400000

However the ondemand governor does not do any upscaling any more - the CPU is 
stuck at 2,4 GHz. It is still possible to use the maximum frequency by setting 
"scaling_min_freq" to "3200000" (or probably by using the performance 
governor).

Is this expected? Could this be a bug? Without limiting the multiplier 
(leaving the default 6/9) ondemand scaling also works as usual (2,4 GHz/3,6 
GHz).

Kernel version: 2.6-git


Regards,
 Daniel

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