external monitor

[Hakan Koseoglu]

norman said the following on 14/04/09 17:54:
> I am using Ubuntu 8.10 with an Inspiron 1525 and I wish to connect an
> external monitor to operate independently and not simply copy the same
> settings as the laptop monitor. I have tried looking in Google but have
> not found anything helpful. The only thing I came across was a reference
> to using the Fn key in combination with the F8 key but when I tried this
> nothing happened. 
> 
> Could some kind person point me in the right direction please from where
> I may get some positive help.
As the other poster mentioned, xrandr is the right tool.

I've done this on a Dell Inspiron 1525 with 8.04, it works.

You might find better tools to do this, please search for other
possibilities first. The following is purely manual hackery, might not be
suitable for newbies.

First thing first, plug all monitors! :) (I still remember a couple of hours
spent futilely trying to get my Eee 701 booting of the network, plugging the
network cable actually helps...)

Then run xrandr all by itself and see what you have.

(This is on my Insp 9400) and I have a 1024x768 VGA and a 1440x900 screen on
the laptop:

hakan at photon:~$ xrandr
Screen 0: minimum 320 x 200, current 2464 x 900, maximum 2880 x 1024
VGA connected 1024x768+0+0 (normal left inverted right x axis y axis) 304mm
x 228mm
   1024x768       60.0*+   75.1     70.1     60.0     59.9
   800x600        72.2     75.0     60.3     56.2
   640x480        75.0     72.8     60.0
   720x400        70.1
LVDS connected 1440x900+1024+0 (normal left inverted right x axis y axis)
367mm x 230mm
   1440x900       59.9*+   59.9
   1280x800       60.0
   1280x768       60.0
   1024x768       60.0
   800x600        60.3
   640x480        59.9
TMDS-1 disconnected (normal left inverted right x axis y axis)
TV disconnected (normal left inverted right x axis y axis)

Note the first line above. My maximum resolution is 2880x1024. Now, this
wasn't so when I started. The default X11 max resolution is much smaller
than this. You would like to change this. Total amount of pixels you used to
be able to have is 2048x2048=4194304 but you might have this in any way you
like and they might have changed this by now. You can check this with
looking at your X11's log file in /var/log.

You increase this with the following modification to /etc/X11/xorg.conf but
first, make a backup!

Section "Screen"
        Identifier      "Default Screen"
        Monitor         "Configured Monitor"
        Device          "Configured Video Device"
        SubSection "Display"
               Virtual 2304 1024
        EndSubSection
EndSection


Add the resolution of your screens in the way you'd like to lay them (the
above is for a 1024x768 + 1280x1024 screen used for the 1525. If you define
a resolution too big or too small, you might end up with gaps or overlapping
areas between the screens.

Test this xorg.conf: sudo X -config /etc/X11/xorg.conf :1

This will start a second X11, if you want to go back to the original, any
time use the keys CTRL-ALT-F7.

Make sure your X runs succesfully! If not, revert to your backup.

If OK, logout and login again (you might like to restart gdm/kdm at that
point as well).

OK, now, remember I had two screens, similar to yours and xrandr recognised
these.

Now decide how you want to lay out your screens. Xrandr has some nifty
options which make things easier.

Some samples:
Put the VGA into the right of LVDS:
xrandr --output VGA-0 --right-of LVDS

Force a particular screen to a particular resolution:
xrandr --output LVDS --mode 1440x900

You can also make these permanent by putting them into the xorg.conf (don't
do it until you're comfortable with the options)
Again, some stuff from my xorg.conf, places foo to the left of bar, sets
them to enabled and defines which one is preferred (and yes, they're really
called foo and bar, go figure).

Section "Monitor"
        Identifier      "bar"
        Option "Preferred Mode" "1440x900"
        Option "Position" "1024 0"
        Option "Enable" "true"
        Option "Preferred" "true"
        Modeline "1440x900"  106.29  1440 1520 1672 1904  900 901 904 932
-HSync +Vsync
EndSection

Section "Monitor"
        Identifier      "foo"
        Option "Preferred Mode" "1024x768"
        Option "Position" "0 0"
        Option "LeftOf" "bar"
EndSection

Hope it works for you.