[Oneiric] Cannot setup dual monitor with AMD 5870

To check if it was hardware related, I have just swapped out the video card for a 5770 and have found the same issues.

The same dialog pops up when running Unity-2D and trying to set the "Displays" app to extend the desktop across both monitors.

Ok, I have a dual boot on this machine.
Both partitions have Oneiric running with fglrx driver now installed.

I have not installed Ubuntu updates on the second partition and the environment is working better.
I only just updated the linux kernel to 3.0.0-12, confirmed no change, then fglrx to 2:8.881-0ubuntu3, again confirmed no change.
Finally upgraded compiz to 1:0.9.6+bzr20110929-0ubuntu1.

Compiz crashes when I try to set the dual monitors up in amdcccle but the desktop does appear altered after it recovers from that crash.

When I reboot, each time the desktop wallpaper for the smaller monitor (1680x1050) appears fine.
The larger monitor is running 1920x1080 but the desktop wallpaper appears to be the same as the 1680x1050 monitor and then repeats (as if tiled).

If I run amdcccle, I can fix them to run at their preferred resolutions and the desktop is redrawn correctly but will always revert when I restart.

The latest version of Unity will not run on this machine = unity_4.20.0-0ubuntu2_amd64.deb

If I revert to a previous version using the commands below, it does work again.

sudo dpkg -i /var/cache/apt/archives/unity-common_4.16.0-0ubuntu1_all.deb
sudo dpkg -i /var/cache/apt/archives/unity_4.16.0-0ubuntu1_amd64.deb

When you're using the open-source Radeon drivers, the xrandr output:
"""
Screen 0: minimum 320 x 200, current 1920 x 1050, maximum 1920 x 1920
"""
indicates that you're using the userspace-modesetting codpaths, rather than kernel modesetting. This is either a result of you passing “nomodeset” to the kernel, or some breakage somewhere.

Status changed to 'Confirmed' because the bug affects multiple users.

do you use nomodeset as suggested? does it work without it?

Hi.

This also affects my system (1920x1080 and 1680x1050 display). Bootoption nomodeset did not make any difference. But with manual configured xorg.conf the problem was solved.

Therefor I added the following section and now it works.

Section "Screen"
    Identifier "Default Screen"
    Monitor "MyScreen"
    SubSection "Display"
        Virtual 3600 1080
    EndSubSection
  EndSection

Regards
Daniel

Addition:
On a second, fresh installed system everything works fine. As the bugopener i had the AMD FGLRX driver installed. I uninstalled it, because of a bug. Perhaps this caused the problem.

Regards
Daniel

Yes there is a fault in the "Display" app probably because of

"As the bugopener i had the AMD FGLRX driver installed. I uninstalled it, because of a bug. Perhaps this caused the problem."

I also get the error after doing the same thing.
required virtual size does not fit available size: requested=(2560, 1024), minimum=(320, 200), maximum=(1280, 1280)

I can only mirror the monitors which is useless for me.

Update. not exactly sure what caused it but the problem was xorg.conf

 seems the old xorg.cofg was renamed to xorg.conf.dist-upgrade-201110070100

and the new xorg.conf only had in it

Section "Screen"
 Identifier "Default Screen"
 DefaultDepth 24
EndSection

Section "Module"
 Load "glx"
EndSection

so I restored the old xorg.conf and everything works.

I just had this problem, the solution I found is quite simple :

# Open Terminal

# Type :
sudo aticonfig --initial=dual-head

# Reboot

Then the Display Setting should be able to activate the second monitor properly.

Hope this helps someone.