Setting up dual screen

[hannv85]

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Hi, im still a little bit new to ubuntu. Basically i have a dell laptop and an external dell monitor (E173FP). I am trying to get this to work as a dual monitor system by changing the xorg.conf file but i dont really know where to start (apart from make a backup of the original xorg.conf file!)

I dont know which lines to change, add to etc... (just a little annoyed cos in windows its so easy to do... )

I've seen loads of xorg files thats other people have posted but still dont get it

thanks in advance

[Glennb]

Hi,

I haven't actually done this on a laptop, but I've done it many times with desktop machines. Hopefully there is some common ground.

I posted some suggestions on how to do this with a Matrox Parhelia graphics card on the Ubuntu Forums a while back. You could check here to see if it helps at all:

http://www.ubuntuforums.org/showthread.php?t=63832

The things to remember when configuring the xorg.conf file are:

1. Each monitor requires its own section in the file.
2. Each 'device' (graphics card, or port on a graphics card) also requires its own section.
3. Each 'monitor' needs to be associated with a 'device' in a separate section called 'screen'. i.e. you will need two screen sections, each of which refers to a 'monitor' and a 'device'.
4. The relationship between the 'screen' sections is laid out in the ServerLayout section. Here you can decide whether 'screen 0' is 'left of', above, or 'right of' 'screen 1'.

It can be a bit of a logic puzzle, and you may need two configurations, one for when the laptop is docked, another for when you don't have the external monitor attached.

The part I'm not sure of is how you will tackle the 'device' section. Many graphics controllers these days have two CRTCs, but this depends on your hardware. In this case (likely) you will need the two 'device' sections to be very similar, like the one shown below:

Section "Device"
	Identifier	"card0"
	Driver		"mtx"
	BusID		"PCI:1:0:0"
Option "HWcursor" "off"
Option "DigitalScreen1" "on"
Screen 0 
EndSection

Section "Device"
	Identifier	"card1"
	Driver		"mtx"
	BusID		"PCI:1:0:0"
Option	"HWcursor" "off"
Screen 1 
EndSection

Make sure that the relationships between each 'device', 'monitor', and 'screen' are correctly set - the 'screen' sections must point to an identified monitor and device.

I hope this is some help in getting you going.

Regards,

Glenn.