I recently decided to upgrade from Ubuntu 12.04 to Ubuntu 13.04 on my Dell Latitude E6400. Everything went smoothly (I did a clean install, actually, so not really an upgrade per se), except the laptop would display an unlit, black screen after resuming from suspend. To fix this, I needed to activate the proprietary Nvidia graphics driver. In Ubuntu 12.04, the open-source Noveau driver worked fine, but not in 13.04.
To activate the driver, open the Software Center and select “Edit” from the program menu, then click on “Software Sources…” at the bottom. After that opens, click on the “Additional Drivers” tab and select the first NVIDIA driver that says:
Using NVIDIA binary Xorg driver, kernel module and VDPAU library from nvidia-310 (proprietary, tested)
I rebooted afterward, just to be sure, although a log out/log in would probably do the trick. Afterward, I could suspend the laptop and resume with no display issues.
Also, if you’re looking to get your wireless working on a Dell E6400, the driver for that is on this same tab as
Using Broadcom 802.11 Linux STA wireless driver source from bcmwl-kernel-source (proprietary)
Ubuntu 12.04 would activate this driver during the OS install, but 13.04 doesn’t do this.