[techtalk] How to do dual screen (display)

[Connie Waring]

OK, it does work under some circumstances......the key deficiency is that
the Nvidia driver does not support OpenGL in a multi-headed configuration
 I'm stuck having to use Nvidia ).

I have RedHat 6.2 and two graphics cards ( one AGP and one PCI ) both with
Nvidia Chipsets (TNT2 and GEFORCE).

Using XFree86 version 4.0 here is how to do it:

- the key sections of the XF86Config file that get changed are:

MONITOR SETUP for SGI GDM20E21 Monitor:

# **********************************************************************
# Monitor section
# **********************************************************************

Section "Monitor"

    Identifier  "SGI Monitor"

# HorizSync is in kHz unless units are specified.
# HorizSync may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY.  REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.

    HorizSync   31.5 - 82.0

#    HorizSync  30-64         # multisync
#    HorizSync  31.5, 35.2    # multiple fixed sync frequencies
#    HorizSync  15-25, 30-50  # multiple ranges of sync frequencies

# VertRefresh is in Hz unless units are specified.
# VertRefresh may be a comma separated list of discrete values, or a
# comma separated list of ranges of values.
# NOTE: THE VALUES HERE ARE EXAMPLES ONLY.  REFER TO YOUR MONITOR'S
# USER MANUAL FOR THE CORRECT NUMBERS.

    VertRefresh 40-150

EndSection



- GRAPHICS CARD DRIVERS ( test is the PCI based card, test2 is the AGP card,
you could switch them if you want ):

Section "Device"
    Identifier  "test"
    Driver      "nv"
    #VideoRam    32768
    BusID      "PCI:0:10:0"
    # Insert Clocks lines here if appropriate
EndSection

Section "Device"
    Identifier  "test2"
    Driver      "nv"
    #VideoRam    32768
    BusID      "PCI:1:0:0"
    # Insert Clocks lines here if appropriate
EndSection

- DUAL SCREEN SETUP

Section "Screen"
    Identifier  "Screen 1"
    Device      "test"
    Monitor     "SGI Monitor"
    DefaultDepth 16

    Subsection "Display"
        Depth       8
        Modes       "640x480" "800x600" "1024x768" "1280x1024"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       16
#        Modes       "640x480" "800x600" "1024x768" "1280x1024"
        Modes       "1280x1024"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       24
        Modes       "640x480" "800x600" "1024x768" "1280x1024"
        ViewPort    0 0
    EndSubsection
EndSection

Section "Screen"
    Identifier  "Screen 2"
    Device      "test2"
    Monitor     "SGI Monitor"
    DefaultDepth 16

    Subsection "Display"
        Depth       8
        Modes       "640x480" "800x600" "1024x768" "1280x1024"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       16
#        Modes       "640x480" "800x600" "1024x768" "1280x1024"
        Modes       "1280x1024"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       24
        Modes       "640x480" "800x600" "1024x768" "1280x1024"
        ViewPort    0 0
    EndSubsection
EndSection


Section "ServerLayout"
    Identifier  "Simple Layout"
    Screen "Screen 1"
    Screen "Screen 2" RightOf "Screen 1"
    InputDevice "Mouse1" "CorePointer"
    InputDevice "Keyboard1" "CoreKeyboard"
EndSection

- NEXT you need to change it so that the Xserver uses the xinerama option so
that it will appear as one giant Xdisplay

if you are using the GNOME desktop, you edit: /etc/X11/cgm/gdm.conf and
change the line that says:

0=/usr/bin/X11/X

to read:

0=/usr/bin/X11/X +xinerama

- Also change /etc/inittab so that the default run level is 5 rather than 3

then reboot and you are dual-screening with a giant X desktop.

I have mine setup for 1280x1024, and 16bit color, but I just arbitrially
chose that.

Thanks,

Connie
============================================================================
==
Connie Waring - Systems Specialist Americas Technology Ctr
SGI, 11490 Westheimer #100, Houston, TX 77077
281-493-8361 cwaring at sgi.com
www.sgi.com www.linuxchix.org