I have an old laptop with a broken charger. The laptop works on the charger but it does not charges the battery. This should not be a problem since the battery is broken also. However I’ve noticed the laptop is very slow. After further investigation I noticed that the cpu maxfreq is always equal the the low frequency no matter the governor:
cat cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
I installed cpufreq and tried setting the governor to performance, no luck. At first the governor was always getting back to ondemand until I realized to stop the ondemand service (update-rc.d remove -f ondemand). Then, even with the performance governor the frequency was never getting as high as it should. Finally after a lot of research I found the following lines which added to /etc/rc.local fixed everything:
echo 1 > /sys/module/processor/parameters/ignore_ppc
echo -n 2000000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
echo -n 2000000 > /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq
Of course you should use your max frequency from /sys/devices/system/cpu/cpu1/cpufreq/scaling_available_frequencies