Workaround for Dell "Power supply not recognised" issue

If you're ready for a hardcore solution, you can unsolder the ID chip from the AC adapter and solder it to the laptop's motherboard or even create a fake ID chip.

An ideal solution would be to patch the BIOS, but I've found only this discussion, nobody did it (yet?)

Can something be done on the software side?

Yes! At least, we can overcome underclocking. Battery won't load.

Linux:

Add processor.ignore_ppc=1 to GRUB_CMDLINE_LINUX in /etc/default/grub, then run update-grub. Reboot.

Windows:

This paper describes Windows XP performance control policies and mentions this:

NOTE: All policies will always respect the highest available performance state currently available as reported in the _PPC method by system firmware, when using the ACPI 2.0 interface.

So, no native support. But there are third-party tools. I personally had success with RMClock, other people in this thread suggest using ThrottleStop instead.

This solved my issue in two laptops, I searched and never came across this so I wanted to post it for someone else. These dell laptops were purchased refurbished with 3rd party chargers, batteries are dell.

8/17/2018 RE: Problem with laptops (E5430)

REINSTALL BATTERY DRIVER - Shut down the laptop - Unplug the AC Adapter from laptop - Remove the battery - Reconnect the AC Adapter to the laptop - Power on - Go the Start and type in Device Manager (search program and files) then Enter - Under Batteries, uninstall Microsoft AC Adapter and Microsoft ACPI- Compliant Control Method Battery (both) - Please note that this will auto-install for you again - Shut down laptop - Remove the AC Adapter from laptop - Insert the Battery and reconnect the AC Adapter - Power on the computer - You should now see the message, Plugged in, Charging

FWIW: I "solved" it by disabling the SpeedStep Technology part in the BIOS.

Although the description there implies that this will then run the CPU at full throttle 100% of the time this not the case in reality. TaskManager shows the frequency to go up and down according to the load.

This does not fix the actual "PSU not recognized"-issue, but at least the machine isn't stuck at 1.18GHz anymore because of that.