[SOLVED] G200. Ubuntu 8.04. Twin screens

This forum is for questions about all G-series cards (G200, G400, G450, ...) that need the mga driver to work properly

[SOLVED] G200. Ubuntu 8.04. Twin screens

Postby JonathanEllis » Sun Jul 12, 2009 12:23 am

Thanks to kind user, penguin42 in the #ubuntu irc channel who helped me fix this.

I am running Ubuntu desktop 8.04 on a Dell Dimension 2400 with a Celeron processor running at 2.4GHz and 1GB of RAM. I installed a G200 with two monitors connected. I disabled the motherboard graphics adapter in the PCs BIOS.

I installed the unofficial driver http://projects.tuxx-home.at/mga/drivers/4.4/matroxdriver_mga-x86_32-4.4.4-installer.run. See http://forum.tuxx-home.at/viewtopic.php?f=11&t=153.

During installation of the driver I selected the option to overwrite the existing driver. I also had to tell the X server to ignore the ABI differences in the Server Flags section.

The critical thing to get the second screen working at all was understanding that the G200 identifies its two outputs with separate PCI addresses. Later cards may use a single PCI address and separate Screen identifiers.

The important thing to get the correct resolution on both monitors was specifying the video RAM in both device sections. Sometimes the video RAM is detected incorrectly and then the system thinks there is not enough RAM for the selected resolution so it tries to output something else. This behaviour seems to vary between when the machine boots up and after the X server is restarted manually.

If you have this problem you will be able to see it in /var/log/Xorg.0.log
Search for "ee" for errors or "ww" for warnings. You could also search for "RAM".

I found both PCI addresses as follows
Code: Select all
$ lspci | grep Matrox
02:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200 AGP (rev 03)
02:04.0 Display controller: Matrox Graphics, Inc. MGA G200 AGP (rev 03)


Do not use Screen n lines in the "Device" sections of org.conf: that is only used on later cards where the two outputs map to a single PCI address.

Oddly enough, I found the G200 second output needs to have it's video mode specified explicitly or it defaults to 800x600. The first output doesn't need this. I don't know why.

Here is my xorg.conf.
Code: Select all
# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#   sudo dpkg-reconfigure -phigh xserver-xorg

Section "InputDevice"
   Identifier   "Generic Keyboard"
   Driver      "kbd"
   Option      "XkbRules" "xorg"
   Option      "XkbModel"    "pc105"
   Option      "XkbLayout" "gb"
   Option      "XkbOptions" "lv3:ralt_switch"
EndSection

Section "InputDevice"
   Identifier   "Configured Mouse"
   Driver      "mouse"
   Option      "CorePointer"   "true"   # Added on advice in http://forums.debian.net/viewtopic.p...r=asc&start=15 to keep mouse cursor from disappearing
EndSection

Section "Device"
   Identifier   "MGA G200 Output 1"
   Driver      "mga"
   BusID      "PCI:2:0:0"           # G200 card has its two outputs appearing as separate devices, each with their own PCI address
   VideoRam            16384         # Card does not detect its RAM correctly. This card has 16MB of RAM per output
   Option      "HWCursor"   "off"   # Added on advice in http://ubuntuforums.org/showthread.php?t=469891 and http://forums.debian.net/viewtopic.p...r=asc&start=15 to keep mouse cursor from disappearing

EndSection

Section "Device"
   Identifier   "MGA G200 Output 2"
   Driver      "mga"
   BusID      "PCI:2:4:0"      # G200 card has its two outputs appearing as separate devices, each with their own PCI address
   VideoRam            16384         # Card does not detect its RAM correctly. This card has 16MB of RAM per output
   Option      "HWCursor"   "off"   # Added on advice in http://ubuntuforums.org/showthread.php?t=469891 and http://forums.debian.net/viewtopic.p...r=asc&start=15 to keep mouse cursor from disappearing
EndSection

Section "Monitor"
   Identifier   "Samtron 94V"
   Option      "DPMS"
   HorizSync          60-70        # You may not need to specify these as the card will attempt to read the available graphics modes
   VertRefresh       58-65        # from the monitor when the card starts up. If you need them, get the figures from your monitor manual.
EndSection

Section "Monitor"
   Identifier   "Hewlett Packard L1800"
   Option             "DPMS"
   HorizSync        60-70        # You may not need to specify these as the card will attempt to read the available graphics modes
   VertRefresh     58-65        # from the monitor when the card starts up. If you need them, get the figures from your monitor manual.

EndSection

Section "Screen"
   Identifier   "Left Screen"
   Device      "MGA G200 Output 1"
   Monitor      "Hewlett Packard L1800"
   DefaultDepth   24

   SubSection   "Display"
      Depth   24
           Modes   "1280x1024"
   EndSubSection
EndSection

Section "Screen"
   Identifier   "Right Screen"
   Device      "MGA G200 Output 2"
   Monitor      "Samtron 94V"
   DefaultDepth   24

   SubSection   "Display"
      Depth   24
      Modes   "1280x1024"
   EndSubSection
EndSection

Section "ServerLayout"
   Identifier   "Default Layout"
   Screen      "Left Screen"
   Screen      "Right Screen" RightOf "Left Screen"
EndSection

Section "ServerFlags"
   Option      "IgnoreABI"   "True"   # This is a workaround to tell the X server to ignore the Module ABI version mismatches introduced by the unoffical MGA driver from http://forum.tuxx-home.at/viewtopic.php?f=11&t=153
   Option      "Xinerama"   "True"   # Turn on twin screens display using the Xinerama option
EndSection
Last edited by JonathanEllis on Sat Nov 07, 2009 12:39 pm, edited 3 times in total.
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