Having Trouble Configuring the Correct Resolution for Monitor

This document (3564938) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Desktop (SLED)
Novell Linux Desktop (NLD)

Notebook or Laptop system with external monitor or projector that requires a different resolution than the internal display.

Any desktop system using the incorrect settings for the display.

Situation

The graphic desktop is not being displayed at the correct resolution or the quality of the graphics is poor.

Resolution

Required Information:

What graphics card is installed in the system?

What is the driver used for your graphics card?

There are two types of drivers for graphics cards, open source and proprietary. Due to the Open Source (GPL) licensing of our products we can only provide the open source versions of the drivers. For ATI and nVidia cards the proprietary drivers will provide additional capabilities and performance such as 3D Acceleration. The proprietary drivers are provided by ATI and nVidia through our update service and can be installed through YaST (Software-->Software Management) or through the zen-installer. They can also be downloaded directly from the manufacturer's site but when a kernel update is done it may require the driver to be reinstalled as the driver is dependent on the kernel version.

For our example here let's assume that we are using an ATI graphics card and the proprietary driver (fglrx) is installed. For other cards just replace the "fglrx" with the driver installed for your card. Here are some common drivers:

Intel: i810
nVidia Proprietary: nvidia
nVidia Open Source: nv
ATI Proprietary: fglrx
ATI Open Source: radeon

Note: Intel made their drivers open source so there is no proprietary driver.

Let's also assume we have a notebook system and we need an external monitor (either on a docking station or plugged into the external port) to display correctly.


First Option (try this easy solution first)

If you can see your graphic desktop on the external monitor but it is the wrong resolution and you are using the GNOME desktop, look at the bottom right in the Notification Area. There should be a Resolution Switcher icon. Click on this icon to change the resolution.

If you are using the KDE desktop just right-click the desktop and select "Configure Desktop".  Select the Desktop icon on the left and make the appropriate changes to the settings.

Second Option (still easy)

If you can see your graphic desktop on the external monitor but it is the wrong resolution or poor quality you can attempt to make a change through YaST under Hardware-->Graphics Card and Monitor.

In the Card and Monitor Properties select the appropriate monitor and resolution. Click OK and when prompted test the configuration.

You can also attempt to use the Dual Head Mode configuration, however, we currently have a limitation that requires the primary and secondary monitors to use the same resolution. So for this example it will not help if it is a resolution issue. This limitation will be lifted in a future release of SLED.


Third Option (more difficult)

Make sure the external monitor is connected to the system and is powered on.

The sax2 utility can be run directly from a command line to probe the monitor for the appropriate settings and allow changes to be made prior to the graphic system being loaded. This is the most reliable way to configure your graphics card and monitor.

1. The system will need to be brought up in runlevel 3 (text only mode) rather than runlevel 5 (graphics mode). To do this reboot the system and when the GRUB boot menu is displayed type the number 3. The 3 will show up in the Boot Options below the menu selection. Press enter to boot the system. When the text Login: prompt is displayed enter root and then the appropriate password.

2. Optional: Backup your current configuration (if it is working at all) which is held in the /etc/X11/xorg.conf file.

cp /etc/X11/xorg.conf /etc/X11/xorg.conf.mybackup

3. The sax2 command will need to be run but there is an easy option that may work and is worth trying first:

sax2 -r

3a. This will load the card and monitor configuration program attempting to discover the correct settings. A graphics screen should be displayed with 3 options. Select "Change Configuration".

3b. Verify that the Monitor is selected correctly. If not, change it.

3c. Verify that the Resolution and Color Depth settings are correct.

3d. When you select OK you will be given a chance to test the settings. Test it. If it looks good then save the changes and exit.

4. If step 3 worked for you then back at the command line enter the command:

init 5

This will startup the graphics system and display your normal login.

If step 3 failed or did not give satisfactory results then proceed with step 5.

5. In this step we will use the sax2 command to identify the driver to be used.

Note: This is how the graphics driver is changed (no GUI interface for this). For example, if you were using the Open Source ATI driver "radeon" but now you have installed the proprietary driver "fglrx" this is how you make the change in the system to use the new driver.

If you attempted to start the graphics system in step 4 you will need to get back to runlevel 3 by running the command:

init 3

Press "Enter" after it runs to return to a command prompt.

For the following command you must know the name of the driver to be used for your card as mentioned above and it must be installed. For this example I will use the ATI proprietary driver "fglrx".

sax2 -r -m 0=fglrx

Note: the 0=fglrx is the numeral zero and not the letter O.

This command should bring up the same graphic interface explained in step 3. Please follow steps 3a-3d above.

6. Once complete return to the graphic Desktop by running the command:

init 5

Or reboot the system.

7. If the new configuration works well it would be a good idea to backup the /etc/X11/xorg.conf again as explained in step 2.

Additional Information

If using a notebook system and a different configuration is required when using an external monitor due to the settings not being compatible with the internal monitor then profiles may be used to boot up using the appropriate settings. This is explained in Technical Information Document number 3268142.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:3564938
  • Creation Date: 25-Mar-2008
  • Modified Date:03-Mar-2020
    • SUSE Linux Enterprise Desktop
    • SUSE Linux Enterprise Desktop

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