Using xrandr or anything to setup multi monitors
 

Hi, i have a laptop and i plunged an external monitor into it. I want to obtain a virtual desktop[ I will privede more debugging info below

video card
01:05.0 VGA compatible controller: ATI Technologies Inc RC410 [Radeon Xpress 200M]

Driver:open source radeon driver
distribution kubuntu 10.04

I tried this:

xrandr --output LVDS --mode 1280x800 --pos 0x0 --output VGA-0 --mode 1920x1080 --right-of LVDS --pos 1280x0

it resulted this error 1
xrandr: screen cannot be larger than 1920x1920 (desired size 3200x1080)

Googling about this error i found a old post,it could be outfated that sugested editing xorg.conf. I created a xorg.conf using "Xorg -configure" and i modified the screen section to this:

Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Modes "1280x800"
Virtual 3200x1080
EndSubSection
EndSection

When trying Xorg -config xorg.conf i get "Fatal server error NO screen found" something like that

I tried with KMS disabled and with it enabled same thing.
Other info
simi@ASUS:~$ xrandr -q
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 1920 x 1920
VGA-0 connected 1024x768+0+0 (normal left inverted right x axis y axis) 477mm x 268mm
1920x1080 60.0 +
1680x1050 60.0
1280x1024 75.0 60.0
1440x900 59.9
1280x960 60.0
1152x864 75.0
1024x768 75.0 70.1 60.0*
832x624 74.6
800x600 72.2 75.0 60.3 56.2
640x480 75.0 72.8 66.7 59.9
720x400 70.1
LVDS connected 1024x768+0+0 (normal left inverted right x axis y axis) 331mm x 207mm
1280x800 59.9 +
1280x720 59.9
1152x768 59.8
1024x768 59.9*
800x600 59.9
640x480 59.4


This is my first atempt to setup multi monitor to work. In pressent the second monitor clones the first one.

The solution is
You need a xorg.conf and you must add a line with Virtual

Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Modes "1280x800"
Virtual 3200 1080
EndSubSection
EndSection

It worked for me.

Thx to all that answered

You will need an xorg.conf file. Please show us the full /var/log/Xorg.0.log file that is generated by Xorg when you used the xorg.conf file you created so we can figure out why it's failing.

Adam

I get this error in the log file

The Virtual keyword must be followed by a width and height value.
(EE) Problem parsing the config file
(EE) Error parsing the config file

Fatal server error:
no screens found

i tried changing the Virtual line to use "" like this

Virtual "3200x1080"

I fixed it, i had to use without that x and wothout quotes


Any idea how to make this permanent? Or it will crash if i will remove the monitor and is better to use a script to launch this mode?
Thx a lot, looking at the log fixed my problem, I have no idea why it do not cross my mind to do that

Virtual is like so:

There is no x between the resolutions.

Adam