Ubuntu: Multi-display Nvidia issue, desktop sliding on secondary display - Ubuntu 14.04



Question:

I've been attempting to configure my laptop with a secondary display. Here's the details:

Laptop: Asus N56V
OS: Ubuntu 14.04 64 bit
Primary display: 1080p laptop display
Secondary display: Samsung UE40H5000 1080p TV
On-board GPU: Intel HD 4000
Dedicated GPU: NVIDIA Corporation GF108M [GeForce GT 630M] (rev a1)
Nvidia driver version: 340.76 from nvidia-340 (open-source)

I normally have Nvidia Prime set to use the Intel GPU and then use optirun to run applications on the Nvidia GPU. However, the Intel GPU doesn't appear to detect when the secondary display is plugged in (it isn't shown in the Screen Display settings). However, if I change Prime to use the Nvidia GPU, both displays are shown.

Mirroring the displays works fine (except for the occasional graphics freeze which I understand is a known bug with the Nvidia drivers). However, if I uncheck mirroring, I get some strange behaviour. At first glance, it appears to be correct - the TV shows the left desktop and the primary display the right desktop. Firstly, the primary display is actually frozen (I can see the cursor on it despite moving it on the other display). Secondly, when I try to move the cursor from the TV to the primary display, the desktop just slides on the TV - that is, it's like I'm pushing the viewport along with my cursor.

Here is what I get if I take a screenshot. I have added the red box to show you the area shown on my TV at the time. If I moved my cursor to the sides, this red box would slide along.

Screenshot

You can also see that nvidia-settings only shows the TV as a display and not the primary display.

Here's my current xorg.conf:

Section "ServerLayout"      Identifier "layout"      Screen 0 "nvidia"      Inactive "intel"  EndSection    Section "Device"      Identifier "intel"      Driver "intel"      BusID "PCI:0@0:2:0"      Option "AccelMethod" "SNA"  EndSection    Section "Screen"      Identifier "intel"      Device "intel"  EndSection    Section "Device"      Identifier "nvidia"      Driver "nvidia"      BusID "PCI:1@0:0:0"      Option "ConstrainCursor" "off"  EndSection    Section "Screen"      Identifier "nvidia"      Device "nvidia"      Option "AllowEmptyInitialConfiguration" "on"      Option "IgnoreDisplayDevices" "CRT"  EndSection  


Solution:1

Extremely likely that you're hooking up the TV to an HDMI port. However, the NVidia is the only graphics adapter that can service the HDMI port internally in your PC as the Intel can not.

What I do before hooking up the TV is to disable the Intel in my BIOS, then the NVidia takes over for everything, and when I unhook it from the TV, I reboot again and go back to Hybrid mode...

Crude, but effective!

(And if you wouldn't believe me: you can also disable the NVidia in the BIOS and then the output of lshw will not show the HDMI port any more! ;-)


Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
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