I have installed Ubuntu 13.04 on a Lenovo T430s. I connected an external monitor via the VGA port (Samsung SyncMaster 2443). When I go to the Display settings, the monitor appears as "unknown", and the maximum resolution is 1024 x 768.
(The maximum resolution is 1920 x 1200 on Windows 7.)
I tried turning Optimus mode on/off, I tried installing Bumblebee, and I tried installing the latest Intel drivers through intel-linux-graphics-installer, to no avail. How can I get Ubuntu to recognize the monitor and/or enable a higher resolution?