Multi Displays don't work on Ubuntu 16.04 GTS250 & NVIDIA Driver 340.102

Hello All,

I’m unable to make my three displays work with the latest NVIDIA driver 340.102 and Ubuntu 16.04

I have two cards GeForce GTS250 - NVIDIA X Server is able to detect both cards and my 3 monitors are recognized correctly. However Ubuntu Unity does not recognize the 2nd and the 3rd. When I move my mouse across displays, I’m able to move it but the cursor changes from an arrow to an X. I can’t move any window across just the mouse. the other two displays remain black (no image).

I tried installing the NVIDIA driver via ppa or directly downloading from NVIDIA. The best combination, I was able to see was all three displays showing the login UI but the login failed each time. I found in the forum that several users are having a login issue due to driver upgrade.

I’m out of ideas. I would like to see a test report from NVIDIA showing how they tested the driver before releasing it.

Please shed some light.

Thanks for your help.

Run and attach output to your post.
Did this work before with an ealier driver version?
If not, multi gpu setups have always been tricky. You will have to use either xinerama (no 3d accel) or basemosaic (proprietary nvidia) and hope unity will get along with that.