resolved by removing iommu=soft option which was preserved from workaround of bug https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1921995 now kernel boots fine and wayland session and amdgpu works fine
** Changed in: xorg (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1947453 Title: wayland black screen with white flashes, display corruption, kernel 5.13 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1947453/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp