nVidia Dual Monitor Switching

My last few machines have had nVidia video cards in them. I'm currently running Ubuntu Maverick 10.04 on a MacBook Pro 7,1. I'm using the nVidia proprietary drivers. Unfortunately, those drivers do not currently support automatically switching between single and dual monitor setup (at the time of this writing it's on their to-do list). In order to solve the problem I found a post about setting up dual "metamodes" in the xorg.conf file and then using xrandr to switch back and forth. This works great and I've created launcher icons in my panel for quickly switching back and forth. Below is a copy of that post from swatkins (just in case the original disappears).

[ SOLVED ] Switch between Dual and Single Monitor I finally found out a nice easy way to do this using xorg.conf and xrandr, which works with nvidia and maybe others.

First, if you didn't already, set up the computer to use both monitors using nvidia-settings, and save the settings. I'm using twinview.

Now make a backup of your /etc/X11/xorg.conf,

sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.before-metamodes.bak

If you need to restore the backup at some time, you'll need to log in to the console (ctrl-alt-f1) and do:

sudo cp /etc/X11/xorg.conf.before-metamodes.bak /etc/X11/xorg.conf

Now, edit /etc/X11/xorg.conf. If you use gedit:

sudo gedit /etc/X11/xorg.conf

find the “metamodes” option, and add a mode for each monitor separately. Mine used to look like this:

Option "metamodes" "CRT: 1440x900_60 +0+0, DFP: 1280x800_60 +80+900"

now it looks like this:

Option "metamodes" "CRT: 1440x900_60 +0+0, DFP: 1280x800_60 +80+900; CRT: NULL, DFP: 1280x800_60 +0+0; CRT: 1440x900_60 +0+0, DFP: NULL"

There are three metamodes there, separated by semicolons ;

To make the single-monitor metamodes, you should just copy the metamode for both monitors, and replace one monitor's settings with “NULL”. Also, change the offset to +0+0.

Now logout and login again, then type:

xrandr

I get:

Screen 0: minimum 1280 x 800, current 1440 x 1700, maximum 1440 x 1700
default connected 1440x1700+0+0 0mm x 0mm
  1440x1700      50.0* 
  1280x800       51.0  
  1440x900       52.0

You can see xrandr now knows about 3 modes, you can select them like:

xrandr -s 0
xrandr -s 1
xrandr -s 2

or:

xrandr -s 1440x1700

If you have two monitors at the same resolution, you can use the first way “xrandr -s 1” etc, or something like:

xrandr -s 1280x800 --rate 51

Nvidia uses the “rate” option in xrandr to distinguish metamodes that have the same resolution.

I tried using nv-control-dpy and some different scripts that I found, it didn't work properly and it's complicated, I think this is a much better and easier way.

After upgrading to Ubuntu 11.10 this no longer worked. Ultimately I found that my “metamodes” line was the problem. I have two monitors with the following resolutions.

The Dell is sometimes connected. As a result I needed to setup two metamodes. I did so by putting a semicolon between them. Here's the “Screen” section of my xorg.conf file.

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "1"
    Option         "TwinViewXineramaInfoOrder" "DFP-0"
    Option         "metamodes" "DFP-0: 1280x800_60 +0+0, DFP-1: 1680x1050_60 +1280+0; DFP-0: 1280x800_60 +0+0, DFP-1: NULL"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Notice that I set the first monitor (DFP-0) to the laptops LCD resolution (1280×800) and I set the second monitor (DFP-1) to NULL. That's because it's not connected in this case.

I have a third case, however, that I had a heck of a time getting to work (under any version). And that is an overhead projector that I sometimes connect to in a conference room and that the NVIDIA driver doesn't correctly detect the display details for. For that, I added a middle option to my “metamodes”. Here's the line with all three options.

Option         "metamodes" "DFP-0: 1280x800_60 +0+0, DFP-1: 1680x1050_60 +1280+0; DFP-0: 1280x800_60 +0+0, DFP-1: 1280x1024_60 +1280+0; DFP-0: 1280x800_60 +0+0, DFP-1: NULL"