12-27-2015 10:28 AM
After doing a clean Windows 10 installation, the DisplayPort on my T520 was not functional. I use it with a DP to HDMI adapter to send output to my TV. The TV was not detected. In the NVIDIA control panel, I noticed that only the 3D Settings section was visible in the left hand menu bar.
In Windows Programs and Features, only the Intel HD display driver installed. I tried installing the Lenovo NVIDIA driver (Win 10 version), which also requires the Intel display driver installed first. The DisplayPort still would not function.
I tried uninstalling all display drivers (Intel included) and letting Windows 10 instal the standard NVIDIA driver. The DisplayPort would still not work.
SOLUTION: Uninstall all display drivers in Windows Programs and Features, both the Intel and NVIDIA. Reboot and hit F1 to enter the BIOS configuration. Go to Config > Display. Change the Graphics Device to Discrete Graphics. Disable OS Detection for NVIDIA Optimus. F10 to save and exit.
Log into Windows and open the Device Manager. Verify that the Display Adapter is using the NVIDIA NVS 4200M driver. The version that is working for me is 10.18.13.5362. In the NVIDIA control panel, all sections and options now show up in the left hand menu bar and the display port works great to my TV via a passive StarTech DP2HDMI2 adapter dongle. When I plug it in, my TV is recognized and the F7 screen toggle works great.
Side Note: After the Windows 10 upgrade, I now have to remove/reinstall the battery prior to the reboot in order to use F1 to get into the BIOS. If I don't remove/reinstall, F1 does not work and Windows boots.