The modeset command fixed this issue for me. I saw a comment above about 'how to'. It's pretty simple:
sudo vi /etc/modprobe.d/radeon-kms.conf and add the following line (press 'o' for Open Line, type in the text, press Esc and then ':wq' for command-write-quit, the colon is important!) options radeon modeset=0 -- [RV530] Video problem: External monitor wavy, unreadable. ati radeon [Needs pll quirk] https://bugs.launchpad.net/bugs/537640 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
