@Kai-Feng. The other bug regarding p-state as disappeared (I cannot access it on Ubuntu bugs). This bug also appears to be fixed as p-state is now the default scaling driver. However tlp stat is showing unusual max/min cpufreq settings after kernel installation. Do these settings seem incorrect and/or are they even used by the pstate driver?

$ sudo tlp-stat -p

--- TLP 0.8 --------------------------------------------

+++ Processor
CPU Model      = Intel(R) Core(TM) i7-7820HQ CPU @ 2.90GHz

/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq  =  3900000 [kHz]
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq  =  3900000 [kHz]

/sys/devices/system/cpu/cpu1/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu1/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu1/cpufreq/scaling_min_freq  =  3900000 [kHz]
/sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq  =  3900000 [kHz]

/sys/devices/system/cpu/cpu2/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu2/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu2/cpufreq/scaling_min_freq  =   800000 [kHz]
/sys/devices/system/cpu/cpu2/cpufreq/scaling_max_freq  =   800000 [kHz]

/sys/devices/system/cpu/cpu3/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu3/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu3/cpufreq/scaling_min_freq  =   800000 [kHz]
/sys/devices/system/cpu/cpu3/cpufreq/scaling_max_freq  =   800000 [kHz]

/sys/devices/system/cpu/cpu4/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu4/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu4/cpufreq/scaling_min_freq  =   800000 [kHz]
/sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq  =   800000 [kHz]

/sys/devices/system/cpu/cpu5/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu5/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu5/cpufreq/scaling_min_freq  =   800000 [kHz]
/sys/devices/system/cpu/cpu5/cpufreq/scaling_max_freq  =   800000 [kHz]

/sys/devices/system/cpu/cpu6/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu6/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu6/cpufreq/scaling_min_freq  =   800000 [kHz]
/sys/devices/system/cpu/cpu6/cpufreq/scaling_max_freq  =  3900000 [kHz]

/sys/devices/system/cpu/cpu7/cpufreq/scaling_driver    = intel_pstate
/sys/devices/system/cpu/cpu7/cpufreq/scaling_governor  = powersave
/sys/devices/system/cpu/cpu7/cpufreq/scaling_min_freq  =   800000 [kHz]
/sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq  =   800000 [kHz]

/sys/devices/system/cpu/intel_pstate/min_perf_pct      = 100
/sys/devices/system/cpu/intel_pstate/max_perf_pct      = 100
/sys/devices/system/cpu/intel_pstate/no_turbo          = 0

x86_energy_perf_policy.cpu0                            = powersave
x86_energy_perf_policy.cpu1                            = powersave
x86_energy_perf_policy.cpu2                            = powersave
x86_energy_perf_policy.cpu3                            = powersave
x86_energy_perf_policy.cpu4                            = powersave
x86_energy_perf_policy.cpu5                            = powersave
x86_energy_perf_policy.cpu6                            = powersave
x86_energy_perf_policy.cpu7                            = powersave

/proc/sys/kernel/nmi_watchdog                          = 0

+++ Undervolting
PHC kernel not available.