CPU frequency scaling (governor) issue (acpi-cpufreq)

[U.Mutlu]

Hi folks,

on my old laptop I've a quadcore 2.5 GHz CPU, but the max freq
the governor switches to goes only up to 2.1 GHz (at idle it's 1.4 GHz):

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2500000 2100000 1800000 1400000

cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
2100000

cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
2500000

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
ondemand

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
acpi-cpufreq


I stress-tested it with a dummy C-program, but as said it never goes above 2.1 
GHz.

Is this a kernel issue, or is it something else? (Btw, I don't use
any external program to manage this, so I assume it's managed by the kernel).

I would like keep the "ondemand", but it of course should also use the 
max_freq when needed.

Kernel: 4.12.0

Thx
U.Mutlu