I have observed a problem with Ubuntu 13.04. The problem was not there on 11.10 I used earlier. The maximum CPU frequency is stuck at 2GHzon my Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz (Dell Lattitude E6320)
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
2000000
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2701000 2700000 2400000 2200000 2000000 1800000 1600000 1400000 1200000 1000000 800000
# echo 2700000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
2000000
I can set scaling_max_freq to a lower value and that works. I can also go back to 2GHz, but not more than that:
# echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
800000
# echo 2000000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
2000000
# echo 2200000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
2000000
Nothing I do seems to help - I have installed TLP, uninstalled it, checked different kernel versions available in 13.04. I have attached and removed the power supply. I have changed the governors and also used the userspace. Regardless of whether I am on AC or battery, the above problem persists.
I have seen people having similar problems before (here, or here), but that was related to a kernel bug back in 2008 and does not seem to be relevant.
Does anyone know how to fix this?