[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: xorg problem--dual-head, Debian vs. Ubuntu



Jesse Sheidlower skrev:
The T60 has a Radeon X1300 card; the built-in monitor runs at
1400 x 1050. I'm trying to attach a 1280 x 1024 external
monitor through the VGA port. I'm running Xorg 1.7.5, and I do
not have an xorg.conf at all, I'm letting Xorg generate the
configuration. When I plug in the external monitor, and run
Display Preferences to try to set up the two displays, I get a
popup message reading "The selected configuration for displays
could not be applied[:] required virtual size does not fit
available size: requested=(2680,1050), minimum=(320, 200),
maximum=(1400, 1400)".


But the notable thing for me is that running Ubuntu 9.10,
which is running Xorg 1.6.4, this Just Works, with everything
else identical--same hardware, same lack of xorg.conf file,
etc.


I have seen the same problem, and I know no solution that does not involve an xorg.conf file. However, I do not think it must be very hard.

When using several monitors, they all form a larger "virtual" desktop together. If you have two monitors of size 1280x1024 next to each other, the "virtual" desktop must be at least 2560x1024 for the two to fit it.

This is adjusted in the xorg.conf file, as follows:

Login as root in text mode (either by booting into recovery mode, or switching with ctrl-alt-F1) and ensure your X is not running (run "/etc/init.d/gdm stop" if you are using a standard gnome desktop).

Then run "Xorg -configure". This should create a file xorg.conf.new with contents suited to your hardware.

Now open that file in a text-editor and look for a "Screen" section to which you add a "Display" section, as shown in this example I found on the internet:


Section "Screen"
       Identifier	"Default Screen"
Device "Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller"
       Monitor		"Generic Monitor"
       DefaultDepth	24

       SubSection "Display"
           Depth		24
           Modes		"1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
# ADD A VIRTUAL LINE TO PROVIDE FOR THE LARGEST SCREENS YOU WILL HOTPLUG
           Virtual              2048 2048
       EndSubSection
   EndSection




Some more information is available on the man page (man xorg.conf).
From the error message you quoted, you may want to choose at least

Virtual	2680	1050

in your configuration.

Now save the file as /etc/X11/xorg.conf and restart X. Hopefully the error is now gone.

If that did not work, you should be able to just delete the file /etc/X11/xorg.conf, and then (after restarting X) you should be back to the configuration you had before.

Somehow ubuntu either uses larger defaults for the virtual screen size, or adjusts them automatically while the xserver is running, but I do not know enough to comment on what is a reasonable default behaviour in general.






Good Luck.


/ johan


Reply to: