Your ThinkPad X1 Yoga Gen 7 (or X1 Carbon Gen 10?)’s OLED display has a “vignette” effect whenever the charger is unplugged. The corners and edges of the display are dimmer/darker than the center.
This is a bug in the older firmware versions that has now been (mostly) fixed by BIOS version 1.25.
- Download the latest BIOS from Lenovo’s website.
- Go through the installer to install the BIOS update. Your computer will reboot.
- In the Settings app, go to System → Display, and click on the arrow to expand the Brightness section.
- Uncheck “Help improve battery by optimizing the content shown and brightness“.
- You may need to close and reopen the laptop for this to take effect.
Speculating the Cause
Making the corners of an OLED display dimmer while preserving brightness in the center would be a convenient way to cheat in brightness-normalized battery life benchmarks. Very suspicious, Lenovo.
Thanks to u/bytemaster0 for sharing the solution!