Linux, Laptops and Dual Displays

I need to update some information related to a post that I made last week about multiple displays with Linux. In a nutshell, I have a laptop and a port replicator with a display connected to it. That gives rise to three basic "states" for display - using the laptop display only (not connected to the port replicator); using the external display only (connected to the port replicator with the laptop lid shut); using both displays simultaneously.

With Windows XP Professional and Vista, the operating system is aware of each of these states, and I can select a resolution for each of them which will then automatically be used as necessary. I can see the result of this by booting the laptop standalone, and getting 1280x800 resolution, then booting with it on the port replicator, and as I open and close the laptop lid, it switches back and forth between 1280x1024 and 1024x768. This is exactly what I would like Linux to do. What I have actually found is:

- Ubuntu (and Kubuntu): Comes the closest to doing what I want. It detects and sets up correctly for laptop only or external only, but I can't get it to do something different for the "both" case.

- Mandriva: I can't even get close; whenever the external display is connected, Mandriva comes up at 640x480, and I can't get it to change from that.

- openSuSE: I can manually select the resolutions for laptop only and external only, the same as what Ubuntu does automatically.

- Fedora: Still investigating. No luck yet.

- Debian: Comes up at 1024x768 no matter what, and I can't find anywhere to change that yet.

jw 22/7/2008