I bought the last of the great Thinkpads...

...and today it had a screen flicker

In a previous article I pat myself on the back for smartsizing and buying the last of the great Thinkpads', the T480, just in time. However today I was not feeling so clever as I woke it up to discover a pretty horendous screen flicker that seemed to go way beyond screen flickering and into damaged or faulty hardware territory. After a couple of reboots, removing the external battery and pondering whether I had attached the 'wrong' (UK plug) cable to the charging brick, it calmed down and stopped flickering. So I did some research as to the likely cause.

It appears that ThinkPad T480 screen flickering is a known issue, particularly linked to PWM (Pulse-Width Modulation) backlight control and dynamic refresh rate switching. Here are the most effective solutions:

• Disable Dynamic Refresh Rate Switching:
  Open Intel Graphics Command Center → Go to System → Power → Disable "Dynamic Refresh Rate Switching". This prevents the screen from flickering when switching between battery and AC power.
• Fix PWM Flickering (for sensitive users): The T480 (especially 1920×1080 models) uses PWM at all brightness levels, which can cause eye strain. While not fully fixable in Windows, disabling dynamic refresh rate helps reduce flicker intensity.
• Linux Fix (Ubuntu 24.04+):
  If using Linux, add these parameters to /etc/default/grub: i915.enable_dc=0 intel_idle.max_cstate=2 Then run sudo update-grub and reboot. This resolves i915 FIFO underrun errors causing flickering. I have in fact 'downgraded' from the Ubuntu 24.04 it came with to Linux Mint 21.3 based on an earlier Ubuntu LTS in order to get the fingerprint reader working and did the same install for the T480 because it is known to have issues.
• Hardware Check:
  Flickering that persists in BIOS or after reseating the eDP display cable may indicate a failing display panel or cable. Check both connectors (left and right) under the bezel.
• Avoid Faulty RAM Slots:
  Some users report flickering only when both RAM sticks are installed. I have indeed upgraded the RAM from 8GB to 16GB with an extra 8GB stick in the second slot. Test with one stick at a time to rule out a faulty memory slot.
• Note: The T480 is widely reported to have flickering issues, especially at lower brightness. If flickering occurs randomly and persists across OSes, it may be hardware-related.