The X Config

Well, I've had at least one email asking about the X Config for my Triple head setup.. So, I thought I'd chuck it up here, explaining the relevant bits.

Ok, to start with, you need to make sure your ServerFlags section turns on Xinerama:

Section "ServerFlags"
    ...
    Option  "Xinerama"  "1"
    ...
EndSection

Then, you need to create some Device sections for each head - with a dual head nvidia card, you can use the Screen option to distinguish between the outputs - I'm not sure if this is specific to the nvidia driver. With multiple cards, you must specify the BusID option - you can find out what the correct value is for your card by running 'X -scanbus' and checking the output (which on my system gets sent to /var/log/XFree86.0.log).

Here's what I use (First two are on a Dual head AGP card, the third is the PCI card):

Section "Device"
    Identifier  "nVidia GeForce FX 5200 - 0"
    Driver      "nvidia"
    BusID       "PCI:1:0:0"
    Option      "NvAgp" "1"
    Screen      0
EndSection

Section "Device"
    Identifier  "nVidia GeForce FX 5200 - 1"
    Driver      "nvidia"
    BusID       "PCI:1:0:0"
    Option      "NvAgp" "1"
    Screen      1
EndSection

Section "Device"
    Identifier  "nVidia GeForce2 MX400"
    Driver      "nvidia"
    BusID       "PCI:5:9:0"
    Option      "NvAgp" "1"
EndSection

Next up, you need to create some relevant Screen sections to go with each of the above. Childs play - this is so far, all bog standard X stuff. I have:

Section "Screen"
    Identifier  "Screen <x>"
    Device      "<device>"
    Monitor     "HP L1925"
    DefaultDepth    24
    SubSection "Display"
        Depth       24
        Modes       "1280x1024"
    EndSubSection
EndSection

Finally, You need to add each Screen to your ServerLayout section, to create a virtual definition of how your physical displays are set up. I have the following (note that the logical order of my displays in relation to the devices defined above is '2-0-1' from left to right)

Section "ServerLayout"
    Identifier  "Default Layout"
    Screen      0 "Screen 0"
    Screen      1 "Screen 1" rightOf "Screen 0"
    Screen      2 "Screen 2" leftOf "Screen 0"
    InputDevice ....
    ....
EndSection

And that's it. X is clever enough to do the rest for you. I'm currently using XFree86 on Debian unstable, but I'd imagine the X.org setup would be somewhat similar.

And just for reference, this is the Device section I used before going to 3 heads, which shows how to use TwinView:

Section "Device"
    Identifier  "nVidia GeForce FX 5200"
    Driver      "nvidia"
    BusID       "PCI:1:0:0"
    Option      "NvAgp"             "1"
    Option      "TwinView"
    Option      "SecondMonitorHorizSync"    "30-82"
    Option      "SecondMonitorVertRefresh"  "60"
    Option      "TwinViewOrientation"       "RightOf"
    Option      "ConnectedMonitor"      "CRT,CRT"
    Option      "MetaModes"   "1280x1024,1280x1024; 1280x1024,NULL"
EndSection

You can use TwinView when you have more that two displays, if you're only using one nvidia card. (this is how Jon Oxer is still using TwinView)

[02:26] [/Work] [permanent link]

Whew!

Well, I've spent a few hours over the last 2-3 days slowly converting all the entries in my blog to use Markdown syntax, mainly thanks to Andrew Cowie's entry regarding his escapades into the blogosphere. I'd wanted to get this sorted out for some time, since I was sick of writing HTML for relatively simple formatting.

Andrew's RSS2.0 and Atom feed code, munges with $ENV{TZ}, but sadly it appears the ctime() that Blosxom uses doesn't react well to it being set, so I took Andrew's code, and added a couple of splatterings of "delete $ENV{TZ};" to get around this. (Basically posts on your web version appear with GMT too, rather than just what's in your Syndicated feeds).

The result of this, is that I now have rss20 and atom 'flavours', in Blosxom speak, for my blog. I decided to use some of those funky little feed icons too. Now, at some stage, I may even get around to learning some CSS to change the look and feel of things... who knows!

[22:23] [/Hacking] [permanent link]