what is the difference between these 3 files. xorg.conf, xorg.conf.failsafe and xorg.conf.nvidia-xconfig-original

Question

How do they differ. What are their functionality. I'm new to ubuntu and i'm using ubuntu 12.04LTS.

Here are their contents.

xorg.conf

 # nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 304.88  (buildmeister@swio-display-x86-rhel47-14)  Wed Mar 27 15:36:45 PDT 2013

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    HorizSync       28.0 - 33.0
    VertRefresh     43.0 - 72.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

xorg.conf.failsafe

Section "Device"
    Identifier  "Configured Video Device"
    Driver      "vesa"
EndSection

Section "Monitor"
    Identifier  "Configured Monitor"
EndSection

Section "Screen"
    Identifier  "Default Screen"
    Monitor     "Configured Monitor"
    Device      "Configured Video Device"
EndSection

• why is xorg.conf.nvidia-xconfig-original empty?
• why does xorg.conf.failsafe lists vesa as driver?

Solution 1

xorg.conf is the one that is being used, if available. It is no longer required, which is why the original was empty; normally, it's not even present, but certain install scripts, such as nvidia, will create backup copies when making a change.

So, the failsafe copy is one that will work, but at a reduced resolution and functionality. It may have been created by an old installer, as I don't think nvidia creates that. But I no longer have nvidia drivers, so I could be mistaken. If you run the nvidia script more than once, you'll end up with more backups.

If there is ever a problem with video, such as no GUI at all, you can often use a terminal to go into the directory and rename the files to change the behavior. In theory, you can rename xorg.conf to xorg.conf.1, or anything else you want, and then copy the failsafe version to xorg.conf.

There is some good information on askubuntu, such as this:

Solution 2

man xorg.conf will give you a lot of information in this sense:

NAME
   xorg.conf, xorg.conf.d - configuration files for Xorg X server

INTRODUCTION
   Xorg  supports  several  mechanisms for supplying/obtaining configuration
   and run-time parameters: command line options, environment variables, the
   xorg.conf  and xorg.conf.d configuration files, auto-detection, and fall‐
   back defaults. When the same information is supplied  in  more  than  one
   way,  the highest precedence mechanism is used. The list of mechanisms is
   ordered from highest precedence to lowest. Note that not  all  parameters
   can  be  supplied via all methods. The available command line options and
   environment variables (and some defaults) are described in the Xserver(1)
   and  Xorg(1) manual pages. Most configuration file parameters, with their
   defaults, are described below. Driver and module  specific  configuration
   parameters are described in the relevant driver or module manual page.

xorg.conf.failsafe file is for the case in which you messed up something on your machine and you need to boot in failsafe mode. For this reason the use of the generic VESA video driver. Again, for more information you can call man vesa:

DESCRIPTION
       vesa  is  an Xorg driver for generic VESA video cards.  It can drive most
       VESA-compatible video cards, but only makes use  of  the  basic  standard
       VESA  core  that is common to these cards.  The driver supports depths 8,
       15 16 and 24.

And finally, for xorg.conf.nvidia-xconfig-original file, again you will find enough information in man pages. man nvidia-xconfig:

   --restore-original-backup
          Restore  a  backup of the X configuration that was made before any
          changes were made by nvidia-xconfig, if such a  backup  is  avail‐
          able. This type of backup is made by nvidia-xconfig before it mod‐
          ifies an X configuration file that it has not previously  touched;
          this  is  assumed  to be an X configuration file that predates the
          involvement of the NVIDIA X driver. As an example,  nvidia-xconfig
          will  copy  an  X  configuration  file  at  /etc/X11/xorg.conf  to
          /etc/X11/xorg.conf.nvidia-xconfig-original the first time it makes
          changes to that file.

Comments

[chanHXC]

i have a question , what if any of those are not present. What configuration file will it read assuming i have nvidia drivers installed.

[chanHXC]

thanks. does than mean that xorg.conf.failsafe is read in case of a missing xorg.conf and sets my driver to vesa even though i have nvidia driver installed?

[Radu Rădeanu]

@chanHXC Exactly.

[chanHXC]

how would i check what driver is loaded in ubuntu. I want to find out if i'm using either vesa or nvidia.

[chanHXC]

i'm confused a bit. I've read that xorg.conf is not much of a use these days. What's the reason for that?

[Radu Rădeanu]

@chanHXC See my answer here

[Deepak Verma]

I believe the open-source nvidia drivers would be used, not the proprietary ones. This is mostly a guess, though, as I now have an AMD video card. I also don't use the proprietary drivers, as the standard drivers work well for me.