Dual Head resolution

[Soheil Hassas Yeganeh]

Dear All,

I have Xorg 6.8.1 on my laptop ( Dell Inspiron 2650 with NVIDIA
GeForce2 Go) and I use the nvidia freebsd driver.It works fine with
Xorg when I'm in "LCD mode". But I have a strange resolution problem
using the second monitor.

When plug a second CRT Monitor and change to CRT or Simul mode ( The
second monitor is activated ) the resolution works fine. ( Both
monitors on 1024x768 )

But when I plug a projector to my laptop and change to CRT or Simul
mode, the resolution is not correct. ( It is something like 640x480 ).

What is the diffrence between a projector and a CRT monitor in
resolution detection ?
Is it about XRandR extension ?