Configure Dual Head with ATI in Ubuntu 9.04

23rd April Ubunty 9.04 Jaunty Jackalope got released. I upgraded my home comp yesterday, and now did my workstation at work today. At home I have an nvidia graphic card, and the upgrade went flawless. At work I have an ATI card and was using the fglrx driver, which seems to be discontinued or something in Ubuntu 9.04.

I did try and upgrade at work yesterday, however I got a warning about the fglrx driver not existing in the next version, so I didn’t go ahead. However since everything went smooth at home I decided to go straight ahead and upgrade my work comp as well today. Things mostly went fine, except I kinda had 2 issues I need to fix asap at work while installing Ubuntu, and I was leaving for a long lunch. During the actual install off the downloaded packages the network driver got disabled, so I was unable to work for about 25 mins.

I did however manage to resolve the issues (well, 1 issue was a IE bug that my superior resolved by saying I should just tell the user to install FireFox (I will justify this at the end off the post)). However, after rebooting my x setup was in clone mode rather than dual head. Which feels like a waste when you have 2 monitors. I tried installing the fglrx driver that is in the Jaunty repository, but that just crashed my computer, and the aticonfig utility didn’t even detect my card for automatic setup.

After going a bit back and forward, it seemed I was going to be stuck with clone mode setup for my 2 monitors, which I was not to happy about. I needed to dig deeper and find some docs on how to actually setup 2 monitors. It turns out that the ati driver in xorg, is just a front package for 3 different ati drivers, and from those 3 drivers I was using the radeon driver. From the docs in that package I was able to locate a page on the debian wiki about the radeon driver. It also deals with the randr util. Checking through my xorg.log file, I did see that the driver did in fact detect my 2 monitors, I just needed to figure out how to configure xorg.conf to properly use them. I tried various solutions and approaches, and I finally got something working:

Section "Device"
  Identifier    "ATI 1"
    Option "Monitor-DVI-0" "Monitor 1"
    Option "Monitor-DVI-1" "Monitor 2"
  EndSection

  Section "Monitor"
    Identifier    "Monitor 1"
    Option    "RightOf" "Monitor 2"
  EndSection

  Section "Monitor"
    Identifier    "Monitor 2"
  EndSection

  Section "Screen"
    Identifier    "Screen 1"
    Monitor        "Monitor 1"
    Device        "ATI 1"
    SubSection "Display"
      Depth           24
      # big virtual screen to place
      Virtual         3360 1050
    EndSubSection
  EndSection

Now I need to explain some details about this setup. Since I have 2 monitors, I just need to define 2 “Monitor” sections in the config file, and in one off them I specify that it’s to the right off the other monitor. I then need to refer to these 2 monitors in the Device section. The way I do this is via the options “Monitor-DVI-0″ and “Monitor-DVI-1″ under the “Device” section. The option names are important here. They need to start with “Monitor-” followed by the device identifier. The device identifier you can find using xrandr. If I run xrandr on my comp, I get the output:

Screen 0: minimum 320 x 200, current 3360 x 1050, maximum 3360 x 1050
DVI-1 connected 1680x1050+0+0 (normal left inverted right x axis y axis) 473mm x 296mm
   1680x1050      59.9*+
   1280x1024      75.0     60.0
   1152x864       75.0
   1024x768       75.0     60.0
   800x600        75.0     60.3
   640x480        75.0     59.9
   720x400        70.1
DVI-0 connected 1680x1050+1680+0 (normal left inverted right x axis y axis) 473mm x 296mm
   1680x1050      59.9*+
   1280x1024      75.0     60.0
   1152x864       75.0
   1024x768       75.0     60.0
   800x600        75.0     60.3
   640x480        75.0     59.9
   720x400        70.1

As you can see here, I have 2 lines starting with a monitor identifier (mine are “DVI-0″ and “DVI-1″). You will also see the same identifiers several places in your xorg.log file. You also need to set the Virtual display size in the “Screen” section. I tried without this first, and ended up with half my monitor being garbled, as the max resolution got set to 2560×1600 or something, less than I need.

If you are going to use my setup on your own comp, you of course need to adjust values to your display setup. Also check what actual identifiers you get for your monitors. My setup is working great with the open source ati drivers, and I also got compiz to work fully. Now I just need to figure out how I can replace xfwm4 with compiz on my home computer, but that is something for a later date.

As for requiering our users to use FireFox instead off IE, the application I am making will in the end have a single client on a single computer, placed on a boat. Since we control everything about this, requiring that one browser is FireFox doesn’t seem like that big off a deal. There will actually be others using parts off the app as well from other browsers, but not the data entry view which has all the JavaScript magic.