I am very interested in getting a quad monitor setup using Ubuntu 12.04. Is this possible with Unity? Will Nvidia X Server automatically detect and configure all 4 monitors making things easy?
I have dug up some bits and pieces of information here and there but don't know what to make of everything.
Quad monitors are certainly possible, here's my setup driven by 2 NVidia cards (using the proprietary NVidia driver):
although, in my particular setup, I wasn't able to make 3D acceleration work, but, as I remember, this was more a requirement of having two of the monitors rotated than having 4 monitors.
Also, I'm not using Unity, the window manager is XMonad, which I would recommend very much for such a setup unless you want to spend hours dragging windows from monitor to monitor and arranging them manually.
I'm using a custom xorg.conf file because, as I remember, I had to specify individual PCI bus IDs for each card to be able to use them - you may be luckier, but generally setting up a multi-monitor machine is an exercise from the "advanced" chapter of the book, do not expect full plug-and-play* (see update below). Again, in my case, rotated monitors complicated the matter a bit.
Here's my xorg.conf:
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" RightOf "Screen3"
Screen 1 "Screen1" 0 0
Screen 2 "Screen2" RightOf "Screen1"
Screen 3 "Screen3" RightOf "Screen2"
Option "Xinerama" "1"
EndSection
Section "Files"
EndSection
Section "Monitor"
# HorizSync source: edid, VertRefresh source: edid
Identifier "Monitor3"
VendorName "Unknown"
ModelName "SamsungSyncMaster"
HorizSync 30.0 - 84.0
VertRefresh 56.0 - 76.0
Option "DPMS"
Option "Rotate" "Left"
EndSection
Section "Monitor"
# HorizSync source: edid, VertRefresh source: edid
Identifier "Monitor2"
VendorName "Unknown"
ModelName "Dell 2007 WFP"
HorizSync 30.0 - 84.0
VertRefresh 56.0 - 76.0
Option "DPMS"
Option "Rotate" "Left"
EndSection
Section "Monitor"
# HorizSync source: edid, VertRefresh source: edid
Identifier "Monitor1"
VendorName "Unknown"
ModelName "BENQ"
HorizSync 30.0 - 81.0
VertRefresh 56.0 - 75.0
Option "DPMS"
EndSection
Section "Monitor"
# HorizSync source: edid, VertRefresh source: edid
Identifier "Monitor0"
VendorName "Unknown"
ModelName "BenQ FP222W"
HorizSync 30.0 - 84.0
VertRefresh 56.0 - 76.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Device3"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce 210"
BusID "PCI:3:0:0"
Screen 1
EndSection
Section "Device"
Identifier "Device2"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce 8400 GS"
BusID "PCI:2:0:0"
Screen 1
EndSection
Section "Device"
Identifier "Device1"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce 210"
BusID "PCI:3:0:0"
Screen 0
EndSection
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce 8400 GS"
BusID "PCI:2:0:0"
Screen 0
EndSection
Section "Screen"
Identifier "Screen3"
Device "Device3"
Monitor "Monitor3"
DefaultDepth 24
Option "TwinView" "0"
Option "metamodes" "DFP: nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen2"
Device "Device2"
Monitor "Monitor2"
DefaultDepth 24
Option "TwinView" "0"
Option "metamodes" "DFP: nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen1"
Device "Device1"
Monitor "Monitor1"
DefaultDepth 24
Option "TwinView" "0"
Option "TwinViewXineramaInfoOrder" "CRT-0"
Option "metamodes" "nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
Option "TwinView" "0"
Option "metamodes" "CRT: nvidia-auto-select +0+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection
Now I'm pretty confident it is possible to plug another video card and extend this to a 6-monitor setup, but I feel the limited flexibility of my neck would not allow me to make a good use of 6 monitors :)
* Mid-2015 UPDATE: Recently I had to boot this machine from a USB stick with Kubuntu 15.04. I have to report that, to my amazement, it recognized and was able to use all 4 monitors without any manual setup (in portrait orientation). Rotating the monitors didn't quite work, but still the progress is impressive - I'm quite sure it only used one or two monitors previously. So I suspect that if you don't want portrait monitors, Kubuntu might work for you out of the box without any tweaks.
I was also able to get quad monitors setup. I did use unity, though I was stuck on unity 2d. The setup was not perfect, there were flaws, but having the extra screen real estate made the hassle worth it.
What kind of flaws? each pair of monitors were treated like a single monitor. Therefor, hitting the maximize button would cause the window to span across two monitors instead of one. Also the feature where you can drag windows to the edge and have it fill up half the screen was broken. Once in a while if I was trying to play a video on monitors 3 or 4, the video would freeze up even thought the audio would keep playing. There were some other glitches like that.
The setup was painful! I spent HOURS digging through blog posts and searching here before I finally figured it out with trial and error.
As Sergey said, you have to use the proprietary NVidia drivers. I don't remember where I found them, but you will not get this to work with the nvidia drivers that auto install. believe me, I have tried! Then you have to build your xorg.conf manually, identifying the hardware and setting the proper settings.
Sadly, back in the Ubuntu 10.x days, this was actually pretty easy... almost plug and play. That all went away with 11.04. =( Things have gotten better little by little since then, but it's FAR from perfect.
