February 20, 2019

Multi-Head Displays in Linux - page 2


  • June 19, 1999
  • By Will Weisner
Multi-head displays in Linux are fairly easy to set up, assuming you have the correct software. In order to run a multi-head display, you first need an X server which supports multiple monitors (the standard XFree86 won't do it). XFree86 4.0, due out later this year, promises to include multi-head support, but until it is released the only recourse is to purchase a commercial server. Two such servers are Metro-X and AcceleratedX.

AcceleratedX is the powerful X server from Xi Graphics, so named because it is reputedly faster than XFree86 on most video adapters. Unfortunately, in order to run a multi-head system with this server, it is necessary to purchase a special edition of it for approximately three hundred dollars. In addition, there is no configuration utility that can deal with setting up multiple monitors, so adding a second screen to your system requires editing the configuration text file by hand.

One advantage Accel-X does have is that it works with a wide range of graphics hardware. You can choose up to eight of any of the cards in this list, as long as those cards are of the exact same make and model.

Metro-X from Metro Link Incorporated, by comparison, has only four video cards available for multi-head setups (although you can install them in different configurations). However, the asking price ($39) is more than low enough to warrant spending a little more on hardware. Because I already owned one of the cards which Metro-X supports (a Matrox Millennium II), I decided to give their server a try.

Setting up Metro-X

Ordering the Metro-X server from Metro Link's web site was easy enough, as was installing the RPMS I found on their secure FTP site. The installation is robust -- it replaces your current XFree86 setup without deleting your old configuration files, which puts you in a position to start working again immediately should you decide to un-install Metro-X later. Especially ingenious is the Metro-X setup utility, which lets you graphically configure all of your monitors and video cards, as well as how monitor orientation is to be treated by the server (Figure 1).

At first I was somewhat miffed, as I was unable to start the X server, receiving only a blank screen for my efforts. However, checking the Metro-X FAQ, I found that the solution was to turn off VGA mode for my second video card (a Matrox Millennium). Kudos to Metro Link for the robust documentation.
Once the server was up and running I had few problems, with the possible exception of problems popping up after leaving the server on for a long period of time. After a day or two, the window manager started mishandling window events causing annoying, random bugs. This seems to be due to some sort of memory leak in the server.

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