Running Debian AMD64, and am trying to get Xinerama functioning with three Nvidia cards (one PCIE, and two PCI).

The Debian installer uses kernel 2.6.8, and this allows Xinerama to activate across all three monitors using the "nv" driver for each.

Upgrading to kernel 2.6.15, and compiling my own kernel, leads to gdm starting but locking up and not displaying the log-on screen. I can see the box for entering the username and password, and the mouse still functions, but I can't type anything, get to the console or see any of the graphics of the log-on screen. In addition to this, the other two monitors are not activated.

If I change "nv" to "vesa" for each graphics card, gdm loads correctly, but only on the primary monitor (the one powered by the PCIE card) - again the other two monitors are not activated. If the PCIE card driver is switched to "nv", and the other two are left as "vesa", gdm will only start up on the primary monitor again.

Is this a bug with kernel 2.6.15, as this is the only thing that changes between successful and unsuccessful Xinerama operation. And is there a work-around of some kind?