I’m trying to get four displays (in a grid layout) going on Ubuntu 12.04 attached to a Quadro NVS 420 card. I’ve tried two configurations.
The first configuration uses Xinerama with four screens. It’s okay, but the mouse pointer glitches out occasionally and skips. Because it uses Xinerama, Unity also ends up being ugly and glitchy.
The second configuration uses base-mosaic mode. This setup is much better than the first in terms of looks and functionality, and is less glitchy with the mouse pointer and with Unity. However, it is unusably laggy. I’ve tried tweaking just about every xorg config option I could find, including the iommu=pt kernel option to no avail.
I’ve tried the 302, 304 and 310 drivers but all of them seem to have the same issues.
Any suggestions for how to get this to work? xorg.conf for base-mosaic mode attached. I think it’s the option I’d prefer to get working, if possible.
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
Option "Xinerama" "0"
EndSection
Section "Files"
EndSection
Section "InputDevice"
# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection
Section "InputDevice"
# generated from default
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "Unknown"
HorizSync 28.0 - 33.0
VertRefresh 43.0 - 72.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
Option "RenderAccel" "true"
VendorName "NVIDIA Corporation"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "nvidiaXineramaInfo" "False"
Option "BaseMosaic" "True"
Option "SLI" "Mosaic"
Option "metamodes" "DFP-0: nvidia-auto-select +0+1200, DFP-1: nvidia-auto-select +1920+1200, DFP-0: nvidia-auto-select +0+0, DFP-1: nvidia-auto-select +1920+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Extensions"
Option "Composite" "Enable"
EndSection