I had to set radeon.modeset=0 to be able to boot. That prevents the module from loading at startup because it needs modeset enabled.
After that, I tried to load the module with: # modprobe radeon modeset=1 Then I got the black screen. I logged in to the system using SSH. The system became extremely slow after loading the module. The attached file is the output of dmesg after loading the radeon module. It was loaded at line 1061. ** Attachment added: "dmesg output" https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1568429/+attachment/4652132/+files/dmesg.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1568429 Title: Radeon won't work with KMS enabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1568429/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs