Linux power management

For x86_64,there are some cpu setting to control the CPU power consumption and therefore CPU power dissipation. On fedora, the package kernel-tools provides tools to handle cpu power management. On debian, the package required is linux-tools-common or ( linux-cpupower ).
Governors are set of rules for scaling cpu frequency. See the kernel documentation for details.
Cpupower example
cpupower frequency-set -g powersave
You can check current governor.
Retrieve governor
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
Setting max and min frequencies
To tune governor, it is possible to set the freq range
Freq range
# set max freq
cpupower frequency-set -u clock_freq
# set min freq  
cpupower frequency-set -d clock_freq
# set the freq ( freq = min = max)
cpupower frequency-set -f clock_freq
Hardware details
Cpupower use kernel module to operate the magic. Its depend on the cpu manifacturer and model.
Driver in use
cpupower frequency-info | grep driver
Available driver can be listed here:
Available driver
ls /usr/lib/modules/$(uname -r)/kernel/drivers/cpufreq/