Cannot Display This Video Mode

Discussion in 'Installation/Configuration' started by g8rbait, Nov 29, 2005.

  1. g8rbait

    g8rbait New Member

    I installed FC4 on a box last week while at a remote location. I brought the box with me to install at another location and can't get the video to display. I get a message that says, "Cannot Display This Video Mode." Is there some way to change the video mode during the boot process? My first thought was to find the same kind of monitor that I had at the other location, but we don't have one. I know I could always install FC4 again, but that is a pain. Any help would be greatly appreciated.


  2. falko

    falko Super Moderator Howtoforge Staff

    You mean you don't see any output on a monitor that is connected to the system? Is the monitor connected properly to the system?
  3. g8rbait

    g8rbait New Member

    Yes, the monitor is connected to the system. I just used a different monitor when I initially installed FC4. I then physically moved the CPU to another location and hooked it up to a different monitor. I installed the Gnome Desktop on the box and changed the monitor display settings during the initial install. The monitor I am using at the new location will not display the settings. I just get a message in the middle of the screen that says, "Cannot Display This Video Mode."

  4. falko

    falko Super Moderator Howtoforge Staff

    Hm, I guess the desktop resolution is too high for your monitor... :confused:
  5. g8rbait

    g8rbait New Member

    Yes, that seems to be the case. I was wondering if there is a way to fix this without having to re-install the whole system again. Granted, it only takes about an hour to re-install, but it's the principal of the thing. Of course, I've learned a valuable lesson: Never set the display above 800 x 600 on a server!
  6. till

    till Super Moderator Staff Member ISPConfig Developer

    You can try to switch with the keys [CTRL] + F1 to a text console, login and search for the file xorg.con with locate:

    locate xorg.conf

    Then open the file with a text editor like vi or joe and set the default resolution to 800x600. Be careful and make a backup of the file before you change anything.

    I'am sorry but i dont know the exact syntax for the screen resolutions.
  7. kariato

    kariato New Member

    Simple work around

    I had the same problem. Try disconnecting the monitor after testing/skipping the media check. With no monitor connected during the VGA probe it defaults to something a LCD monitor will use. I now this seems to simple to work but I had a lot more success with this method than changing the xorg.conf file which I've always hated.
  8. wselectric

    wselectric New Member

    Use FC5 Rescue CD To Change Display Mode

    I just installed Fedora Core 5 and the installer was unable to recognize my monitor (it came with a Compaq Presario 1725). So, I chose a monitor from the list that seemed close to mine, and tried to set the resolution at 1280x1024. MISTAKE!! It seems that my monitor doesn't support that high resolution. The screen was snow. I had downloaded the FC5 Rescue CD from Red Hat so I booted it and went into Rescue Mode. From there I went to the shell prompt and entered the command "chroot /mnt/sysimage", then edited one (1) line in the file /etc/X11/xorg.conf as follows (only pertinent section shown):
    Section "Screen"
    Identifier "Screen0"
    Device "Videocard0"
    Monitor "Monitor0"
    DefaultDepth 24
    SubSection "Display"
    Viewport 0 0
    Depth 16
    Modes "800x600" "640x480"
    SubSection "Display"
    Viewport 0 0
    Depth 24
    Modes "1024x768" #changed from "1280x1024"

    After editing the xorg.conf file, I exited out of the shell (type exit twice), and the system rebooted in 1024x768 mode. And it looks very nice! Thanks for your help.
  9. sbovisjb1

    sbovisjb1 Member HowtoForge Supporter

    Configuring your monitor

    I hope this helps some:p
    * If Fedora did not recognize your monitor during installation open a terminal and log in as root ("su -" ).

    * Type:

    gedit /etc/X11/xorg.conf

    Hit enter and gedit will open. Scroll down to the "Monitor" section. Find the "HorizSync" line and enter your monitor's supported horizontal frequency range. The line should look something like "HorizSync 30.0 - 70.0". Enter your monitor's supported vertical frequency range opposite "VertRefresh". The line should look something like "VertRefresh 50.0 - 160.0". Scroll down to the "Screen" section and opposite each instance of "modes" enter you monitor's supported pixel resolution, starting with the highest. The line should look something like "Modes "1024x768" "800x600" "640x480"". You should be able to get these values from your monitor's manual or from a search for your monitor by manufacturer and model number on the Internet. Use caution when entering these values and be sure that they conform to your monitor's published specifications or you could be left with a non-working graphical environment. Hit the "save" button in gedit and exit gedit. Log out and log back in.

    * Click "System" > "Administration" > "Display". Type your root password in the dialog box presented and hit enter. Click the down arrow on the right of the "Resolution:" box and select your preferred pixel resolution. Click the down arrow on the right of the "Color Depth:" box and select your preferred color depth. Log out and log back in.

    * Click "System" > "Preferences" > "Screen Resolution". Click the down arrow on the right of the "Resolution:" box and select your preferred pixel resolution. Click the down arrow on the right of the "Refresh rate:" box and select the highest refresh rate available. A refresh rate of 85 Hz or more will decrease noticeable flicker significantly and may eliminate it completely. Click "Apply".

    Caution!Special warning regarding mixing incompatible repositories for software installation and updates:

    * We will be using the program applications Yum and Yumex described below as methods to obtain software and to update your Fedora Core installation. You will be configuring these programs by adding repositories which are groups of software created by third party packagers that we use in addition to original Fedora Core and Fedora Extras repositories that come standard with your new installation.

    As you continue please keep the following in mind: You should not use the repository in conjunction with the dag/freshrpms/dries/newrpms (RPMforge) collection of rpms in your configuration files for automatic updates. Use one group or the other but not both. These two groups are mutually incompatible and can cause errors in your installation if used together for automatic updates. Regardless of which group you choose you should also avoid using the ATrpms repository in your yum or apt configuration files for these reasons.( Some additional information can be found here.(

    With this being said please note that it is nonetheless possible to obtain single RPM packaged applications from incompatible third party repositories in cases where such packages do not create errors when installed with yum. More specifically it is possible to configure other repositories with their enable flags set to "0" (off) so that the yum "--enablerepo" command must be used when one of those packages is desired.
  10. frivvy89

    frivvy89 New Member


    I had the same problem. I just hit F8 to boot to safe mode and enable vga mode and that was it.
  11. aduel

    aduel New Member

    I already knew it!

    reboot your pc then simultaneously press f1 then press f8 then choose lowest resolution then change the resolution in the time you are using your pc (after the error came). :))
  12. jzlin88

    jzlin88 New Member

    Use another monitor with higher resolution

    I had the same problem. The screen says "Cannot dislay this mode. Optimun resultion 1280x1024". But hitting F8 doesn't bring me to the safe mode.

    However, I was able to use anther monitor that has a higher resolution to get back to the screen, and then:
    - On desk top, right click mouse.
    - proerties,
    - settings,
    - changed to 1280x1024 pixels

    Done, back to work.
  13. jzlin88

    jzlin88 New Member

    On a second thought, this is not a good solution

    On a second thought, this is not a good solution. When I swithch the monitor back and reboot, the problem comes back showing the "Cannot Display This Video Mode" again. I still need a better solution.

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