The recent xorg server does not support the old xinerama setting, precisely Option "MonitorLayout" in the Device Section. The old configuration of xorg.conf are
2007/03/05 - [computer/linux] - Xinerama on Ubuntu 6.10 with open source driver
2008/02/06 - [computer/linux] - modified xorg.conf file

I spent several days to understand this inconvenient HISTORY about xorg. Finally everthing is o.k. now.

Now,  a part of the brand-new xorg.conf file is
Section "Monitor"
        Identifier      "Laptop"
        HorizSync       28-64
        VertRefresh     43-60
        Gamma           1.0
        Option          "DPMS" "true"

Section "Monitor"
        Identifier      "DellE177FPf"
        DisplaySize     339.92  270.336
        HorizSync       30-81
        VertRefresh    56-76
        Gamma           0.9
        Modeline        "1280x1024_75.00"  135.00 1280 1296 1440 1688 1024 1025 1028 1066  -HSync +Vsync
        Option          "PreferredMode" "1280x1024_75.00"
        Option          "RightOf"       "Laptop"
        Option          "DPMS" "true"

Section "Device"
Identifier      "Radeon Mobility X700 (RV410 PCIE)"
        Driver          "ati"
        BusID           "PCI:1:0:0"
        Option          "Monitor-VGA-0" "DellE177FPf"
        Option          "Monitor-LVDS"  "Laptop"

Section "Screen"
        Identifier      "Default Screen"
        Monitor         "Laptop"
        Device          "Radeon Mobility X700 (RV410 PCIE)"
        DefaultDepth    24
        SubSection "Display"
                Depth           24
                Virtual         2560 1824

Section "ServerLayout"
        Identifier      "Default Layout"
        Screen          "Default Screen"
        InputDevice     "Synaptics Touchpad"
        Option          "BlankTime"           "10"
        Option          "Standby"               "20"
        Option          "SuspendTime"       "30"
        Option          "OffTime"               "40"

But, The methods which are well-described in the following references are not the solutions to my laptop.

Now, the classic story is ....

1. Monitor Section
There are two monitors: one is the laptop panel, the other is an external monitor, for me Dell E177FPf.  In the xorg.conf, the gray colored texts are "optional" that is not critical for my machine.

The Dell monitor spec is on and is listed in the more


DisplaySize is calculated according to as

horizontal = resolution*dotpitch = 1280*0.264 = 337.92,
vertical = resolution*dotpitch = 1024*0.264 = 270.336,

or xdpyinfo | grep -B 2 dot

The references suggest to use "gtf" or "cvt" to get Modeline, but I could not get the correct ModeLine by this. Fortunately, I have another linux machine to use the same monitor, I looked into /var/log/ file, then I found the correct modeline.

gtf returns
 gtf 1280 1024 75 -x

  # 1280x1024 @ 75.00 Hz (GTF) hsync: 80.17 kHz; pclk: 138.54 MHz
  Modeline "1280x1024_75.00"  138.54  1280 1368 1504 1728  1024 1025 1028 1069  -HSync +Vsync

cvt returns
 cvt 1280 1024 75
# 1280x1024 74.90 Hz (CVT 1.31M4) hsync: 80.30 kHz; pclk: 138.75 MHz
Modeline "1280x1024_75.00"  138.75  1280 1368 1504 1728  1024 1027 1034 1072 -hsync +vsync

other machine
(**) NV(0): *Default mode "1280x1024": 135.0 MHz, 80.0 kHz, 75.0 Hz
(II) NV(0): Modeline "1280x1024"  135.00  1280 1296 1440 1688  1024 1025 1028 1066 +hsync +vsync
(**) NV(0):  Default mode "1280x1024": 108.0 MHz, 64.0 kHz, 60.0 Hz
(II) NV(0): Modeline "1280x1024"  108.00  1280 1328 1440 1688  1024 1025 1028 1066 +hsync +vsync
(**) NV(0):  Default mode "1280x960": 108.0 MHz, 60.0 kHz, 60.0 Hz

2. Device Section
Using lspci |grep VGA
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility X700 (PCIE)
Thus,     BusID           "PCI:1:0:0"

For ATI driver, outputs of the video card are
  • LVDS  : laptop panel
  • VGA-0 : RGB output
LVDS and VGA-0 are called "outputname" in the man page of xorg.conf (line around 650 man xorg.conf). This can be checked by xrandr -q.

3.  Screen Section

Virtual is calculated  by

Laptop panel is 1280x800, and the dell monitor 1280x1024
1280+1280 = 2560
800+1024 = 1824

4. Final screenshot

posted by citadel

For ubuntu 8.04 see 2008/12/17 - [computer/linux] - xorg.conf with an external monitor

Five days ago, I was so boring to understand one textbook about beam physics. Then I just upgraded my Ubuntu 6.06 to 6.10 with update-manager -c -d command.  Roughly one hour later, I totally realized what the stupid thing I did. Fortunately, my old ROOT GUI,  GEANT4 program, and tools were worked fine. But my dual head configuration did not work very well. I found fgrlx driver worked fine except a strange square mouse cursor, which ate my screen, on the external monitor. Definitely Digging into xorg.conf was starting........ T__T

Whatever methods which I found on the web did not work on my machine.After I lost three days to understand the xorg.conf file, finally everything works fine. Not MergedFB but xinerama method. MergedFB method did not work for me. That gave me the wrong resolution on the external monitor.

  • Specifications
    • Samsung R50
    • 01:00.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility X700 (PCIE) (result of "lspci")
    • Ubuntu 6.10 (OS)
    • VGA driver "radeon" (open source driver)
    • Laptop LCD (Resolution:1280x800, HorizSync:28-64, VertRefresh:43-60)
    • External Flat LCD/TFT(?) : Dell E177FPf (Resolution:1280x1024, HorizSync: 30-81,        VertRefresh:56-76)
  • What I want
    • When I boot up my ubuntu 6.10 without external VGA cable, only single LCD works.
      • After boot up, when I extend my scrren with xinerama option, just connect VGA cable. And restart server.
    • When I boot up my ubuntu with an external VGA cable, xinerama option works with two different resolution monitors.

Here is my xorg.conf file

more.. xorg.conf

In the configuration file, most important line is   Option          "MonitorLayout"         "LVDS, AUTO"  in "Device" Section.  Ubuntu forum said "LCD, CRT" ,"LVDS, CRT", "CRT,CRT", or whatever combination were recommended. But All combination failed for me.
Only possible option is "LVDS,AUTO".

Here is /var/log/Xorg.0.log  with grep EE and WW

more.. Xorg.0.log

I have no time to solve this. Just ignore DRI configuration.

This was Bug #22985 . It was solved with xserver-xorg-video-ati-1:6.6.3-2ubuntu3.

MergedFB also works but I must do some tricky thing.
  1. boot up my laptop with the xinerama configuration file.
  2. 1 can activate the external monitor.
  3. change xorg.conf with xmergedFB file
  4. restart gdm.
  5. more.. xorg.conf with MergedFB

Here is the screenshot.
사용자 삽입 이미지

And /var/log/Xorg.0.log files

more.. Xorg.0.log

posted by citadel