[Bug 97042] Re: Wrong CPU scaling frequencies

Jarmo Ilonen trewas at gmail.com
Wed Apr 11 12:29:26 UTC 2007


*** This bug is a duplicate of bug 82242 ***
    https://bugs.launchpad.net/bugs/82242

Speedstep-centrino (which is now used by default) gives worse frequency
scaling choices for me too on Thinkpad X41, compared to acpi-cpufreq.
With kernel linux-image-2.6.20-14-generic version 2.6.20-14.22
speedstep-centrino gives:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
798000 1064000 1330000 1596000 

And with acpi-cpufreq:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
1600000 1500000 1400000 1300000 1200000 1100000 1000000 900000 800000 600000 

So the acpi-cpufreq gives more choices for the frequency and most
importantly can go 200mhz lower. This used to work fine a few weeks
back, I am not sure when it changed but I think it was kernel version
2.6.20-13. It has one suspicious comment in changelog,

linux-source-2.6.20 (2.6.20-13.21) feisty; urgency=low
  * speedstep-centrino: Include linux-phc built-in tables.
    - GIT-SHA fc9f7238d11d5a9ff03ce67fae0b5b5c9fd7f436
    - Bug #63789

How come speedstep-centrino is used anyway? It was disabled in

linux-source-2.6.20 (2.6.20-3.4) feisty; urgency=low
  * debian/config: Disable speedstep_centrino in favor of acpi_cpufreq.
    - GIT-SHA 2a0e7ef37fb8db5953f4c467219552835d7dddd8

and changelog doesn't mention reverting that.

-- 
Wrong CPU scaling frequencies
https://bugs.launchpad.net/bugs/97042
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