"FreeBSD Handbook": 5.4 X11 Configuration

[Zbigniew Baniewski]

Hallo,

I would to suggest to add information about configuration using RandR.
I had much trouble lately finding out, why my well-tested configuration
isn't working anymore - until I've learned, that newer versions of video
drivers were designed especially to utilize RandR during video configuration,
and because of this some functionality (f.e. "panned virtual screen") are
(temporarily?) lost.

It should be stressed, that RandR isn't just a tool to check-out available
video-modes, but the quite new way to configure video, which supposingly
required serious changes in video drivers.

http://www.thinkwiki.org/wiki/Xorg_RandR_1.2

And f.e. http://lists.freedesktop.org/archives/xorg/2008-March/034166.html

#v+
  The radeon driver got xrandr 1.2 support.  Previous versions of the
  driver assumed one monitor per driver instance while with xrandr you
  may have several monitors.  With xrandr it is much more important to
  get mode information about each monitor since you may have two or more
  monitors connected with vastly different capabilities.  The previous
  version of the driver more or less always assumed a monitor was
  connected and forced whatever mode you specified.  You can still do
  this, but as you see, the configuration has changed a bit.  This page
  should give you a good overview:

  http://www.intellinuxgraphics.org/dualhead.html
#v-

-- 
				pozdrawiam / regards

						Zbigniew Baniewski