Display Problems

Use the following topic to troubleshoot color- and display-related problems:

Scattered Desktop Display

When configuring a desktop session using an X client command (for example gnome-session, startkde, or Xsession), your desktop elements appear scattered on your Windows desktop. This can be the result of your session settings. Change your session definition to use Show clients on X terminal desktop.

Color Allocation

You may see one of the following errors if an X client makes an unsuccessful color request, typically because the client wants to create a new color and cannot:

  • X Error of failed request: BadAlloc
    Major opcode of failed request: 84 (XAllocColor)
  • X Error of failed request: BadAlloc
    Major opcode of failed request: 86 (XAllocColorCells)
  • X Error of failed request: BadAlloc
    Major opcode of failed request: 87 (XAllocColorPlanes)

To resolve color allocation errors

  • Change the Default Visual Type setting in the session Display tab from a static color model (TrueColor, 24-bit depth) to a dynamic color model (PseudoColor, 8-bit depth).

OpenGL Applications

Many OpenGL applications require a TrueColor visual. On the session Display tab, check the Default Visual Type. If this is set to PseudoColor, 8-bit depth, you'll see colors flashing when 3D graphics are displayed. Configure the session to use a higher color depth to eliminate the flashing. Select either <Best Visual> or TrueColor, 24-bit depth.

TrueColor

If the X client application you are running expects a default visual type that allows the colormap to be changed, you cannot use TrueColor, 24-bit depth as the Default Visual Type. Doing so may prevent the client from starting, and result in an error message.

For example, attempting to run the ico2 client using the following command:

ico2 -faces -dbl -colors gray blue yellow

...results in an error message, as follows:

"Server can't support dynamic colormaps"

-or-

"BadMatch (invalid parameter attribute)"

If you attempt to run the X client xfishtank with TrueColor, 24-bit depth selected as the Default Visual Type, the following error message appears:

"Don't know how to format image for display of depth 24"

Some clients do not return an error message. Instead, gray, hatched patterns are displayed in place of the correct colors.

If you are running an X client that exhibits any of these problems, select PseudoColor, 8-bit depth as the Default Visual Type.

Note: A Default Visual Type setting of <Best Visual> often results in a setting of TrueColor, 24-bit depth.

Related Topics

Display tab