[tentacleuno]

Update: looks like you were right[0], although it doesn't affect my 2013 Latitude, if Linux's cpufreq diagnostics are anything to go by.

   # Running on battery power.
   cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
   3500000
   3500000
   3500000
   3500000

   # No-name charger inserted.
   cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
   3500000
   3500000
   3500000
   3500000

   # Genuine charger inserted.
   cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
   3500000
   3500000
   3500000
   3500000

[0]: https://unix.stackexchange.com/questions/576692/ignore-ppc-s...

[invalidator]

Try applying load to the CPU and see what cpuinfo_cur_freq reports. If I boot my ThinkPad W530 (workstation laptop with a large power envelope) with no / dead battery, it will say full speed is available, but it will remain at the minimum speed until the battery is partially charged and I reboot.