My laptop has two graphics cards. First, an Intel integrated video card, second Nvidia GeForce GT330M. When I had installed Ubuntu and used it as my primary OS I had mostly problems with the display output setup.
On Ubuntu 11.10 I could switch the display output configuration for the Intel card without rebooting or the need to restart the X server. Newly attached monitors or projectors were detected without a problem. When I activated Nvidia drivers and started to use the external video card I couldn’t do it any more via normal system settings. I had to use Nvidia’s tool and it almost in all configuration steps required an X server restart or a reboot, which resulted in closing running applications.
Since I am using a laptop it’s normal to change the display settings while the system is running. I couldn’t imagine myself restarting my laptop when I had to connect a projector.
I installed Ubuntu 12.04 LTS with the help of Wubi (Windows Ubuntu Installer). When Ubuntu boots up it’s running just like a native installation with access to the physical hardware. I checked the new Nvidia drivers and Nvidia settings tool. Now I am able to use TwinView, which allows me to extend my screen to a secondary display, without closing my applications. I checked with HDMI and D-Sub outputs and it works. I couldn’t setup a screen clone, but the screen extend possibility is enough.
Choose ‘Apply’. A confirmation window with a 15 second countdown will appear, probably on the secondary screen. In case of HDMI the monitor detected the signal quickly and displayed the picture. With D-Sub connection I had to wait a little and quickly hit the OK button to confirm that the new video settings are good.
All the changes were made on a running system with additional applications started. After changes, applications were still running and there were no problems with the extended screen. Even detecting newly attached displays without rebooting works great. No problems with projectors, or at least I hope so, because I tested this only with my external monitor.