I have a small problem with my Thinkpad T480s. After I updated it from Fedora 29 to 30, and an external screen is connected to it, my laptop screen flickers sometimes. Note that I use XORG instead of Wayland.
I've tried several things already:
I tried to install the latest stable kernel from Vanilla
Added these options in GRUB_CMDLINE_LINUX in the file
intel_iommu=on,igfx_off i915.enable_psr=0 i915.enable_rc6=0. And updated the GRUB by using
sudo grub2-mkconfig -o /boot/grub2/grub.cfg.
I also did an BIOS update to version 1.31.
All these things didn't work.
For information, DMESG:
[drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun