Comment 12 for bug 1124328

That is funny. For me everything worked fine after upgrading 14.04. The dual monitor set up works briliantly after using the additional driver package for ati radeon graphic card adapters (fglrxx-updates).

It stopped working and producing exactly the same behaviour after working on another issue with compiz (skydome, cube rotating not working properly under 14.04). After trying to fix that, it fails, and the dual monitor vanished after logging in, leaving two black blank screens. In the error log there were repeatedly the above mentioned message.

The odd workaround works (plugging off), after changing from Terminal 8 to 7 again (ctrl-alt-F8 and then ctrl-alt-F7 again), then immediately the second monitor came back again....