Validate CPU scaling governance inputs against available options

[farshidtz]

rt-conf/src/model/pwrmgmt.go

Lines 17 to 21 in f0a9cfe

	var scalProfilesMap = map[string]ScalProfiles{
	"balanced": balanced,
	"powersave": powersave,
	"performance": performance,
	}

The possible scaling governor value depends on the CPU and drivers. The values should be validated against the available ones.

Example:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
performance powersave

[farshidtz]

Similar issue with min/max frequency. The input validation could consider the allowed range:

$ cd /sys/devices/system/cpu/cpu0/cpufreq/
$ grep . cpuinfo_m*
cpuinfo_max_freq:5600000
cpuinfo_min_freq:800000

Also note that for some CPUs, scaling_available_frequencies lists the supported frequencies; see:

• https://wiki.archlinux.org/title/CPU_frequency_scaling
• https://web.archive.org/web/20201029114421/https://software.intel.com/sites/default/files/comment/1716807/how-to-change-frequency-on-linux-pub.txt
• https://askubuntu.com/questions/1064269/cpufrequtils-available-frequencies