In enablement, we had a case of the driver not loading that was causing this issue bug 934528. Additionally there was a report of the video switch hotkey not functioning, but that was because the driver was not installed by jockey bug 959438. If we're in optimus mode and jockey is installing the nvidia driver, and we're still having problems with video out, then this looks to be a regression from oneiric.
In enablement, we had a case of the driver not loading that was causing this issue bug 934528. Additionally there was a report of the video switch hotkey not functioning, but that was because the driver was not installed by jockey bug 959438. If we're in optimus mode and jockey is installing the nvidia driver, and we're still having problems with video out, then this looks to be a regression from oneiric.