Comment 2 for bug 289566

Hi!

I did some more testing today.

It is working almost now. It's a bit tricky to explain.
One big problem was caused by compiz.

Without compiz, I could configure a dualscreen,
that worked almost, but 256 pixel in horizontal direction on
the Mac screen were still cloned (two mouse pointers, ...)

Compiz version: 1:0.7.8-0ubuntu4.1

I try to explain what I did step by step.

1. boot MacBook WITHOUT external monitor attached,
compiz enabled and with a std xorg.conf:
Section "Monitor"
 Identifier "Configured Monitor"
EndSection

Section "Screen"
 Identifier "Default Screen"
 Monitor "Configured Monitor"
 Device "Configured Video Device"
EndSection

Section "Device"
 Identifier "Configured Video Device"
EndSection

2. attach external monitor
3. start gnome-display-properties
4. laptop screen and external screen are detected with their native resolution:
 1280x800@60Hz and 1680x1050@60Hz
5. i configure dualscreen. The external remains black
It asks me to set virtual resolution.
xorg.conf

Section "Monitor"
 Identifier "Configured Monitor"
EndSection

Section "Screen"
 Identifier "Default Screen"
 Monitor "Configured Monitor"
 Device "Configured Video Device"
 SubSection "Display"
  Virtual 2960 1050
 EndSubSection
EndSection

Section "Device"
 Identifier "Configured Video Device"
EndSection

(Looks correct.)

6. I alt-ctrl-backspace out of X and login again
7. The dualscreen is buggy: the resolution of both monitors is correct
(1280x800 and 1680x1050), but it is not one big dualhead screen.
On the laptop screen there seems to be a smaller screen within,
with a resolution of 1024x768. I can 't move the mouse outside this
area. By dragging a window to the external monitor I can "free" the mouse.
On the other display is no refresh of the background, when compiz
enabled. See the two pictures. On the pictures you can also see
from the background picture, that the desktop is totally confused.

When I disable compiz, the refresh problem is gone, but invicible borders
remain
8. I alt-ctrl-backspace out of X and login again
9. Now it works almost! Both screens have the right resolution.
On the laptop there is still the smaller screen within (1024@768),
but no invicible boardes. The rest of the screen in horzontal dir
 (from 1024 to 1280= 256 pixel)
is a cloned area of the left beginning of the external area. For these
256 pixel the mouse will appear on both screens. The desktop backgound
is still as confused as on the pictures.