http://navetz.com/v/132/Simple-dual-monitor-setup-with-XrandR-in-Ubuntu-Linux

I also have a intel chipset, and the process is pretty easy. You just need to modify one line in your xorg, and write a small script when you are done.

I have HP dv1597 and a 19″ CRT. I managed to dualhead with xrandr, but there is something anoying, when I enbable the CRT and put it on left of the internal LCD, the main screen is the CRT.

Is there anyway of keeping the main screen(panels) in the internel screen?

I’ve just been using it to set up the internal and external displays on my laptop to mirror to a projector, but you can also use it to set up single extended workspaces across multiple monitors with varied resolutions.

I have to say that my experience was that it isn’t bombproof and bug-free yet, but persistence and a few restarts of X got me to a working system with less trouble than I usually get by trying to edit the xorg.conf file directly.

Section “Device”
Identifier “1 Matrox Graphics, Inc. MGA G450 DualHead AGP”
Driver “mga”
BusID “PCI:1:0:0″
Screen 1
Option “OldDmaInit” “True”
EndSection

Section “Monitor”
Identifier “0 E95″
Option “DPMS”
EndSection

Section “Monitor”
Identifier “1 E95″
Option “DPMS”
EndSection

Section “Screen”
Identifier “Primary Screen”
Device “0 Matrox Graphics, Inc. MGA G450 DualHead AGP”
Monitor “0 E95″
DefaultDepth 24
SubSection “Display”
Depth 1
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 4
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 8
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 15
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 16
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 24
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
EndSection

Section “Screen”
Identifier “Secondary Screen”
Device “1 Matrox Graphics, Inc. MGA G450 DualHead AGP”
Monitor “1 E95″
DefaultDepth 24
SubSection “Display”
Depth 1
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 4
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 8
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 15
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 16
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
SubSection “Display”
Depth 24
Modes “1600×1200″ “1280×1024″ “1280×960″ “1152×864″ “1024×768″ “832×624″ “800×600″ “720×400″ “640×480″
EndSubSection
EndSection

Section “ServerLayout”
Identifier “Xinerama Layout”
Screen 0 “Primary Screen”
Screen 1 “Secondary Screen” RightOf “Primary Screen”
InputDevice “Generic Keyboard”
InputDevice “Configured Mouse”
InputDevice “stylus” “SendCoreEvents”
InputDevice “cursor” “SendCoreEvents”
InputDevice “eraser” “SendCoreEvents”
Option “Xinerama” “True”
EndSection

Modes “1920×1200″ “1440×900″

even though this is not supported by the smaller display. and magically everything works at the right resolution on both displays with or without the external monitor connected.

I use Xrandr because it rocks.

Reset your Xorg.conf files back to the defaults with dpkg-reconfigure. Unplug your external monitor and restart X.

Plug it back in and in a command line type
“xrandr”

You should see a bunch of output listing all monitors attached. My external monitor is called “VGA” but yours may be different, if so replace it where appropriate.

Turn this monitor on with:
xrandr –output VGA –auto
OR
xrandr –output VGA –mode 1024×768

This should enable it in mirror mode.
Obviously this isn’t what you want, so we turn it into a Xinerama setup by typing
xrandr –output VGA –left-of LVDS

(LVDS is the name given to the inbuilt screen)

During that you will probably experience an error message about “not having a big enough virtual screen size”

This is because the intel driver allocates a certain amount of memory for storing the screen contents, it is able to make the screen smaller, but not allocate more memory on the fly.

You can see the maximum size allowed int he first line of xrandr’s output:
“Screen 0: minimum 320 x 200, current 1280 x 800, maximum 1280 x 800″

To get round this we change our “Display” option in xorg.conf to read like this:

SubSection “Display”
Depth 24
Virtual 2560 1024
Modes “1280×1024″

EndSubSection

Where the two values in “Virtual” represent the maximum total screen size needed.

Another note is there is a “bug” with the Intel graphics driver. You cannot have a super large resolution and 3D acceleration both on by default. I believe there is a way round this with 2 framebuffers but it’s all a bit complex.

Disable it like this:

# Load “glx”
# Load “dri”

Email me if you you have any further questions. Hope this helps.