setting up external display

elephantos · 2008-10-06 23:28:11

Hugely noobish issues here -

1) I have an external VGA monitor hooked up to my thinkpad and it's displaying a clone of the laptop screen in the same resolution. how can I set the display to extended?

2) how do I exit an X server without rebooting or X automatically restarting?

output of $ xrandr

Screen 0: minimum 320 x 200, current 1024 x 768, maximum 1600 x 1050
VGA connected 1024x768+0+0 (normal left inverted right x axis y axis) 474mm x 296mm
   1024x768        60.0* 
LVDS connected 1024x768+0+0 (normal left inverted right x axis y axis) 304mm x 228mm
   1024x768       60.0*+   50.0  
   800x600        60.3  
   640x480        60.0     59.9  
TV disconnected (normal left inverted right x axis y axis)

e: btw, intel 945gm integrated graphics

e: updated problem 1. i got it to display in clone.

Last edited by elephantos (2008-10-10 00:16:30)

elephantos · 2008-10-10 00:15:14

bump

phrakture · 2008-10-10 03:17:06

Oh the woes of external monitors. Frankly, this is something I've always wanted to be better in linux, but it's just so hard.

If you're working with xrandr and not xinerama or dualview or anything fancy like that, xrandr is fairly simply to use, but a pain.

Firstly, let's say you want each monitor at 1024x768. If you're going to display them side-by-side, then to total desktop would be 2048x768. You need to set this as the VirtualSize in xorg.conf. I use the following:

Section "Screen"
    Identifier "MainScreen"
    #Device     "FglrxDriver"
    #Device     "RadeonDriver"
    Device     "AtiDriver"
    Monitor    "MainLCD"
    DefaultDepth 24
    SubSection "Display"
        Depth     24
        Virtual 2680 1050
    EndSubSection
EndSection

Note that this needs to be square. My thinkpad is 1400x1050 and the external monitor is 1280x1024. That means, side by side the size is 2680x1050. Note the disparity in 1024 vs 1050. That causes issues sometimes.

Set the virtual size and restart X.

Now we can have fun with xrandr.

$ xrandr --output VGA --auto --left-of LVDS

This little snippet will do... we exactly how it reads. "output VGA left of LVDS". These identifiers are spit out in the xrandr input. Read the man page for all the options such as --left-of --right-of and the like. --auto just tells xrandr to use the "preferred resolution and settings" for the monitor, but you can specify the geometry and depth and refresh manually if you so please.

You can also shut off a display with:

$  xrandr  --output VGA --off

Some useful links:
* Automatically detect external displays when X starts: http://www.thinkwiki.org/wiki/Xorg_Rand … t_on_login
* Blog about basically what I just wrote: http://andrew.mcmillan.net.nz/node/62
* A GUI by Keith Packard of xorg fame: http://gitweb.freedesktop.org/?p=xorg/app/grandr.git
* A script for Fn-F7 key presses to toggle display patterns: http://www.thinkwiki.org/wiki/Sample_Fn-F7_script

Let me know if you have any more questions or ideas. I always wanted to get this working flawlessly on Linux. The biggest hiccup is the need for the Virtual setting.

Arch Linux

#1 2008-10-06 23:28:11

setting up external display

#2 2008-10-10 00:15:14

Re: setting up external display

#3 2008-10-10 03:17:06

Re: setting up external display

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