Using the Xinerama Extensions to MultiHead X V. 4.0
Dennis Baker
[email protected]
v1.0, May 2, 2000
This document describes how to configure XFree86 Version 4.0 with Mul�
tiple monitors and the Xinerama extentions.
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Table of Contents
1. Introduction
2. Planning
3. Video Card set up.
4. Scan the PCI Bus
5. Editing your XConfig File
5.1 Adding all of your video cards
5.2 Identifying Your Video Cards
5.3 Configuring the ServerLayout Section
6. Testing Your Configuration
7. Editing your startup files
8. Sample XF86Config Files
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1. Introduction
This is not meant to be a guide on how to set up your specific
monitor, or videocard. In fact, I assume that you already have X
windows running for your setup. Please refer to the XF86
Documentation for more information.
As far as I know, there are no limits to which video cards you can
configure this way, nor does it seem to matter if you mix different
types of video cards in a setup, The sample configuration I use in
this documentation uses two different video cards, a AGP Fire GL 1000
and a PCI Matrox Millenium II. What effect this has on 3d
Accelleration I don't know as I don't currently accellerate either of
my video cards.
This Howto assumes that you know how to edit text files, do basic
video card configuration for X Windows, add and remove hardware from
your system, start and stop system services, and follow simple
instructions. If feel you will have trouble with any of these things,
please seek help. I am not responsible if you damage any of your
stuff.
2. Planning
Planning a Xinerama setup is pretty straight forward. There as
essentially three things you need to take into account, screen
resolution, color depth, and screen layout.
It is possible to have each physical screen in your Xinerama setup to
have a different resolution. There are some advantages to this, I was
able to use an old monitor which only operates at 640x480, and a
bigger 17" at 1280x1024 in my setup. I have also heard of web
developers and graphics designed who use one big "preview" screen and
flank it with one or two smaller screens. I think this is one of the
great things about the Xinerama extensions.
There is one significant problem with using multiple screen
reolutions. Current generation window managers assume the screen is
rectangular and will assume this rectangle is equal in size to the
heighth and width of your total desktop. If you have one monitor at
1600x1200 and another at 800x600, your window manager will assume
your desktop is 2400x1200. This leaves a big area below the smaller
screen which the window manager interprets as "Empty", many window
managers will try to utilize this space for new windows. There are
ways to configure your window manager to minimize this problem but is
a nuisance. As window managers become Xinerama aware and this problem
will go away quickly.
Unlike with screen resolotion, Xinerama limits your entire virtual
screen to one color depth. If you were planning on pulling out a
cheap video card for your second display you need to keep this in
mind. If your old video card only supports 8 bit color you might get
a bigger display but most newer programs look lousy in 256 colors.
Layout decisions are fairly simple, you just need to decide how you
want to lay out your monitors. Most people will simply place their
monitors in a row and view their desktop as one giant monitor. It is
also possible to overlap displays, or place them in more complex
layouts. Keep in mind though what I said above about window managers
expecting rectangular displays.
3. Video Card set up.
This is a good time to back up your existing config file: I did it
like this:
root# > cp /etc/X11/XF86Config /etc/X11/XFree86Config.working
Before we start the multihead portion of this process you need to have
ALL of your existing cards working properly with the display they will
have in the final configuration. If you haven't already, configure
and install each different video card/ monitor combination you are
going to have in your final setup. If you have several identical
video cards you can get away with configuring one and copying the
configuration for the other cards.
After you have each card set up, back up or print it's config file as
you will need it later. Here's how I did it:
root# > cp /etc/X11/XF86Config /etc/X11/XFree86Config.Matrox
If your video cards are identical you can probably get away with just
one copy. However don't skip this step, If all else fails this will
be you backup config file incase my instructions lead you astray.
Once you have all of your displays configured you are almost there...
4. Scan the PCI Bus
This is a good time to put all of your video cards into your system
and set up your monitors. Set everything up the way you want it when
you are done, as you will have to repeat steps later if you change
things.
This next step needs to be done from the console with-out X running.
If you are in X, exit now. If your system uses a display manager such
as xdm or gdm exit you need to stop that service. If you need to stop
a display manager from RedHat the easiest way is like this:
root# > telinit 3
for Debian, Storm or Corel :
root# > /etc/init.d/xdm stop
If neither of these methods work you, reboot your computer and start
up in single user mode.
In a multi-head setup you need to explicitly identify each video card
in your config file. To do this you need to use the PCI Bus
Identifier your system assigns the card. At this time, all video
cards need to be in your system.
To find out what your PCI bus IDs are:
root# > XFree86 -scanpci
X will then output a code for each device on your PCI bus.
______________________________________________________________________
(0:0:0) Intel 82443BX Host
(0:1:0) Intel 82443BX AGP
(0:7:0) Intel 82371AB PIIX4 ISA
(0:7:1) Intel 82371AB PIIX4 IDE
(0:7:2) Intel 82371AB PIIX4 USB
(0:7:3) Intel 82371AB PIIX4 ACPI
(0:9:0) Adaptec 2940U/UW
(0:11:0) 3COM 3C900 10b Combo
(0:12:0) Matrox unknown card (0x2007) using a Matrox MGA 2164W
(1:0:0) unknown card (0x1092/0x0152) using a Texas Instruments Permedia 2
______________________________________________________________________
PCI cards and devices are identified with a leading 0, AGP cards with
a 1. In my case I have a Matrox Millenium II (0:12:0) and a Diamond
FireGL(1:0:0). Find your video cards and write down the numbers
associated with them. It is important that you know which number goes
with which card.
5. Editing your XConfig File
If I haven't lost you so far, we are in the home stretch now. This
section is pretty confusion so I suggest you also read the manpage for
XF86Config, or at least skim it. Do it now... I'll wait.
root# > man XF86Config
5.1. Adding all of your video cards
Open your current XF86Config file and scroll down to the Monitor
Section. You want to copy the following sections from the XF86Config
backup files you created above : Monitor, Device, Screen. These
sections should go in your XF86Config file after the coresponding
section in the file you have open. As you copy each section make
certain that the Identifier is unique for each section, you will
reference these identifies later.
Clear as Mud Right? You should now have a Monitor Section, a Device
Section, and a Screen Section for EACH video card/monitor
combination, each Section should have a unique Identifier. If you are
still confused reread the prior paragraph. If that doesn't help, look
at the sample ``'' I have included at the end. You did read the
manpage right?
5.2. Identifying Your Video Cards
Now you need to add the coresponding PCI BusID as an option at the end
of each Device Section. The entry should look like this: BusID
"PCI:0:12:0", substituting the three numbers with the PCI bus ID
which identifies YOUR video card you should have this ID from the
``''. Here is a sample Device Section for one of my video cards.
______________________________________________________________________
Section "Device"
Identifier "FireGL"
Driver "glint"
BusID "PCI:1:0:0"
EndSection
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Please note, even AGP cards use this layout.
5.3. Configuring the ServerLayout Section
Now you need to edit the ServerLayout Section at the end of the
XF86Config File. The ServerLayour Section is exactally that, it
tells you what Screens to use, how to lay them out logically, and what
input devices to assign to them. Your current layout is for one
screen, keyboard, and mouse. For each Screen section you have created
about you need reference in this section for them to appear in your
display.
Using the existing screen reference as a starting point, create
additional references for your other Screen Sections. The reference
looks like this:
Screen "Screen 2" Relationship "Screen 1"
This defines the relationship between the "Screen 2" and "Screen 1".
Valid Relationships include: RightOf, Below, Above, LeftOf, Absolute X
Y, Relative. Use of the first four relationships is pretty obvious as
illustrated in my sample:
______________________________________________________________________
Section "ServerLayout"
Identifier "Simple Layout"
Screen "Screen 2"
Screen "Screen 1" RightOf "Screen 2"
InputDevice "Mouse1" "CorePointer"
InputDevice "Keyboard1" "CoreKeyboard"
EndSection
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I have other examples in the ``'' section.
6. Testing Your Configuration
Once you have completed changing your XF86Config file, save it and
your can now test your configuration :
root# > startx -- +xinerama
Hopefully you can now enjoy X with multiple partners... er that is,
Monitors.
7. Editing your startup files
If this worked you will probably want to change your X configuration
to start X this way automatically. There are lots of ways to do this
and there are probably better ways than what I've shown below. Here
are the methods I used for changing startx and gdm.
If you run X from the command prompt add the +xinerama option to the
startx script.
root# > vi /usr/X11R6/bin/startx
At the very end of the file the script starts X with the command
xinit. Add the +xinerama option to the very end of that line.
To Configure gdm to start with the xinerama extentions look for
[servers] section at the bottom of /etc/X11/gdm/gdm.conf. Add the
+xinerama extension to the end of the line that starts with 0=. It
should look like this :
0=/usr/bin/X11/X +xinerama
I am certain configuring KDE, and xdm to start xinerama are equally
easy, if you figure it out please drop me a note and I will add it to
this Howto.
8. Sample XF86Config Files
My current XF86Config File :
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Section "Module"
Load "dbe" # Double buffer extension
SubSection "extmod"
Option "omit xfree86-dga" # don't initialise the DGA extension
EndSubSection
Load "type1"
Load "freetype"
# This loads the GLX module
# Load "glx"
EndSection
Section "Files"
RgbPath "/usr/X11R6/lib/X11/rgb"
FontPath "/usr/X11R6/lib/X11/fonts/local/"
FontPath "/usr/X11R6/lib/X11/fonts/misc/"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi/:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi/:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/Type1/"
FontPath "/usr/X11R6/lib/X11/fonts/Speedo/"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi/"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi/"
# The module search path. The default path is shown here.
# ModulePath "/usr/X11R6/lib/modules"
EndSection
Section "ServerFlags"
EndSection
Section "InputDevice"
Identifier "Keyboard1"
Driver "Keyboard"
Option "AutoRepeat" "500 30"
Option "XkbRules" "xfree86"
Option "XkbModel" "pc101"
Option "XkbLayout" "us"
EndSection
Section "InputDevice"
Identifier "Mouse1"
Driver "mouse"
Option "Protocol" "PS/2"
Option "Device" "/dev/psaux"
EndSection
Section "Monitor"
Identifier "Mini"
HorizSync 31.5
VertRefresh 50-90
EndSection
Section "Monitor"
Identifier "Impression"
HorizSync 31.5 - 82.0
VertRefresh 50-100
EndSection
# Video Card #1, Matrox Millenium II PCI Video Card
Section "Device"
Identifier "Matrox"
Driver "mga"
VideoRam 8192
BusID "PCI:0:12:0"
EndSection
# Video Card # 2, Fire GL 1000 AGP video card.
Section "Device"
Identifier "FireGL"
Driver "glint"
#VideoRam 8192
BusID "PCI:1:0:0"
EndSection
Section "Screen"
Identifier "Screen 2"
Device "FireGL"
Monitor "Impression"
DefaultDepth 16
Subsection "Display"
Depth 16
Modes "1280x1024" "640x480"
ViewPort 0 0
EndSubsection
EndSection
# My Miniature monitor, notice that I used the virtual option so it is
# the same heighth as the larger monitor, this is not necessary.
Section "Screen"
Identifier "Screen 1"
Device "Matrox"
Monitor "Mini"
DefaultDepth 16
Subsection "Display"
Depth 16
Modes "640x480"
ViewPort 0 0
Virtual 640 1024
EndSubsection
EndSection
Section "ServerLayout"
Identifier "Simple Layout"
Screen "Screen 2"
Screen "Screen 1" Rightof "Screen 2"
InputDevice "Mouse1" "CorePointer"
InputDevice "Keyboard1" "CoreKeyboard"
EndSection
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An alternate ServerLayout Section with one Monitor above the other.
______________________________________________________________________
Section "ServerLayout"
Identifier "Simple Layout"
Screen "Screen 2"
Screen "Screen 1" Below "Screen 2"
InputDevice "Mouse1" "CorePointer"
InputDevice "Keyboard1" "CoreKeyboard"
EndSection
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Screens can overlap too. In this configuration I make the two
monitors overlap by 80 pixels..
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Section "ServerLayout"
Identifier "Simple Layout"
Screen "Screen 2"
Screen "Screen 1" Relative "Screen 2" 1200 0
InputDevice "Mouse1" "CorePointer"
InputDevice "Keyboard1" "CoreKeyboard"
EndSection
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