powersaved: frequency scaling not working [FIX included]

Bug #68423 reported by Arnaud on 2006-10-26
Affects Status Importance Assigned to Milestone
powersave (Ubuntu)

Bug Description

Binary package hint: powersaved

VERSION: using fully updated kubuntu edgy.

- Frequency scaling is not working


- powersaved fails to load cpu frequency governors, and frequency scaling doesn't work


- at the start of the load_governors() function, script /etc/init.d/powersaved checks for readable "/sys/devices/system/cpu/cpu0/cpufreq". And that folder doesn't exist _at that time_. If the folder does not exist or is not readable, cpu freq governors kernel modules are not loaded.


- the folder "/sys/devices/system/cpu/cpu0/cpufreq" is created by the kernel after the appropriate cpufreq module is loaded (in load_cpufreq_modules() function)


- load_governors() is called too early after loading cpufreq module

a quick FIX:
- in function load_cpufreq_modules() of /etc/init.d/powersaved, a small delay could be introduced between the loading of cpufreq module and the call to load_governor. I tried a sleep .2 which was too short, but a sleep 1 works perfectly.

Hoping this reporting is useful, thanks for your work

Arnaud (arnaud-oss) on 2006-10-29
description: updated
Benjamin Wohlwend (piquadrat) wrote :

I can confirm that adding sleep 1 before load_governor fixes the problem.

This problem seems to also affect laptops when coming out of sleep

Daniel T Chen (crimsun) on 2008-08-28
Changed in powersave:
importance: Undecided → Low
status: New → Confirmed
Arnaud (arnaud-oss) wrote :

This is history, closing...

Changed in powersave (Ubuntu):
status: Confirmed → Invalid
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