Home » Blogs » ramez hanna's blog

Linux Dual Screen

i spent a long time trying to configure X to work with my two screens (one being the laptop screen and one being an external LCD) 

The VGA card is: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)

i want to have my desktop streched out over the two screens, and don't ask why i wanted that, at that time i thought it was cool

so i tried all i can with Xorg configuration and always ended up with the same: X fails to start and i have to restore the backup config and start over 

until it just hit me one day on the internet, at the place i should have lookd at the begining, intel's website!

http://www.intellinuxgraphics.org/dualhead.html

three simple steps

 

  1. in a termianl run #xrandr -q
  2. xrander --output <some screen> --auto
  3. xrandr --outpout <same screen> --right-of <other screen>

example

#xrandr -q
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 1280 x 1280
VGA disconnected (normal left inverted right x axis y axis)
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis) 261mm x 163mm
  1280x800 59.9*+ 60.0 
  1280x768 60.0 
  1280x720 60.0 
  1024x768 60.0 
  800x600 60.3 
  640x480 59.9 
TMDS-1 disconnected (normal left inverted right x axis y axis)

now  connect the second monitor

xrandr -q
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 1280 x 1280
VGA disconnected (normal left inverted right x axis y axis)
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis) 261mm x 163mm
  1280x800 59.9*+ 60.0 
  1280x768 60.0 
  1280x720 60.0 
  1024x768 60.0 
  800x600 60.3 
  640x480 59.9 
TMDS-1 disconnected (normal left inverted right x axis y axis) 
  1440x900 59.9*+ 60.0 
  1280x768 60.0 
  1280x720 60.0 
  1024x768 60.0 

now you see that first when no screen attached LVDS was connected

the when the external screen was connected TMDS-1 apeared to be connected andthe VGA is disconnected, now VGA is for a n analog connected lcd, TMDS-1 is for digital dvi connected lcd

these names vary with different drivers so every card vendor would have his own names.

this would only work with xrandr 1.2 and above