Discovered that fglrx (ATI binary drivers) only enable stereo for cards with a physical stereo connector (a mini-DIN port). This is annoying, because a number of stereo goggles have VGA pass-throughs to get the sync. That means there’s a little plug that plugs directly into the monitor VGA port on the computer, and it has a plug on it for your monitor cable. It also has a little cable going off for the stereo goggles.
This came up because I thought stereo should be enabled (the X log said so), but in reality I didn’t get any stereo visuals. I’m trying to convince ATI to add a ForceStereo option that’s at least available for all FireGL cards, if not all cards their drivers support.
Also, a couple people asked what stereo is. Basically, it’s viewing a 3D object using a 2D screen and some special goggles. Usually, the screen alternates a “left eye” image and a “right eye” image at >=120Hz, and the goggles are required to blank out the wrong eye so you see a true stereo image at ~60Hz. It’s useful for visualizing any 3D objects (molecules, ocean simulations, buildings, probably geology for geoman), and some games can use it too. Tom’s Hardware has a decent review from May 2005.