Comment # 22 on bug 1179387 from Nikolai Nikolaevskii

https://forums.opensuse.org/showthread.php/547620-Tumbleweed-DVD-i586-Snapshot20201123-graphical-mode-fail?p=3002500#post3002500

Developers are throwing away AGP code:

https://www.phoronix.com/scan.php?page=news_item&px=AGP-Radeon-Nouveau-Drop-RFC
https://www.phoronix.com/scan.php?page=news_item&px=Radeon-AGP-GART-Disabling-Patch
https://lists.freedesktop.org/archives/dri-devel/2020-May/265527.html
https://lists.freedesktop.org/archives/amd-gfx/2020-May/049540.html
https://lists.freedesktop.org/archives/amd-gfx/2020-May/049541.html

Try to use PCI-only mode for AGP port or PCI video cards.