I am running Ubuntu on a Raspberry Pi 4B and have run into an issue with the KMS driver and overscan. When running dtoverlay=vc4-fkms-v3d the overscan settings apply correctly to keep the display from escaping the screen boundries. However, when I switch to dtoverlay=vc4-kms-v3d the boot process starts correctly but switches halfway through the boot process.
Is there a setting I am missing that controls overscan for KMS other than commenting out disable_overscan=1 in /boot/firmware/config.txt?
Thanks.
