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How To Change Screen Resolution on ARM Ubuntu for Raspberry Pi 4

Ubuntu 19

In this article, we will walk you through the steps to change the screen resolution on ARM Ubuntu for Raspberry Pi 4. This guide will be helpful if you are running Ubuntu on your Raspberry Pi 4 and need to adjust the screen resolution to suit your needs.

Quick Answer

To change the screen resolution on ARM Ubuntu for Raspberry Pi 4, you can use the xrandr command to list the available resolutions and then set the desired resolution using the same command. If that doesn’t work, you can edit the usercfg.txt file located in the /boot/firmware directory. Add the appropriate configuration for your display and restart your Raspberry Pi for the changes to take effect.

Understanding Screen Resolution

Screen resolution refers to the clarity of the text and images displayed on your screen. It is determined by the number of pixels that can be displayed on the screen, measured horizontally and vertically. Higher resolution means more pixels, which results in sharper and clearer images.

Checking Available Resolutions

Before we begin, it’s important to know what screen resolutions are available for your display. You can do this by using the xrandr command, which is a utility for configuring screen resolution and refresh rate.

Open a terminal window by pressing Ctrl+Alt+T and run the following command:

xrandr -q

This command will list all the available screen resolutions. Look for the resolution you want to set from the list.

Changing Screen Resolution

Once you’ve identified the desired resolution, you can change it using the xrandr command again. Here’s how to do it:

xrandr --output default --mode <desired_resolution>

Replace <desired_resolution> with the resolution you identified from the list. For example, if you want to set the resolution to 1920×1080, the command would be:

xrandr --output default --mode 1920x1080

In this command, --output specifies which output to configure (in this case, the default output), and --mode sets the resolution.

Troubleshooting

In some cases, the above steps might not work and you might receive an error message saying “Failed to get size of gamma for output default”. If this happens, you can try an alternative solution.

This involves editing the usercfg.txt file located in the /boot/firmware directory. You can open this file with a text editor such as nano, by running the following command:

sudo nano /boot/firmware/usercfg.txt

Add the following lines to the file:

[HDMI:0]
hdmi_group=2
hdmi_mode=82
hdmi_drive=2

[HDMI:1]
hdmi_group=2
hdmi_mode=82
hdmi_drive=2

This configuration is for a Raspberry Pi 4 with two HDMI outputs. The hdmi_group parameter refers to the type of display connected (in this case, a monitor), hdmi_mode sets the resolution (82 corresponds to 1920×1080), and hdmi_drive sets the HDMI signal type (2 corresponds to HDMI mode).

Save the changes and exit the text editor. Then, restart your Raspberry Pi for the changes to take effect.

Conclusion

Changing the screen resolution on ARM Ubuntu for Raspberry Pi 4 can be a bit tricky, but with the right commands and a little bit of patience, you can easily adjust it to your liking. Always remember to backup any important files before making changes to system configurations. Happy tinkering!

How do I check the current screen resolution on ARM Ubuntu for Raspberry Pi 4?

You can check the current screen resolution by opening a terminal window and running the command xrandr -q. This will list all the available screen resolutions.

How do I change the screen resolution on ARM Ubuntu for Raspberry Pi 4?

To change the screen resolution, use the xrandr command followed by the --output and --mode options. For example, to set the resolution to 1920×1080, the command would be xrandr --output default --mode 1920x1080.

What should I do if the above steps don’t work and I receive an error message?

If you encounter an error message saying "Failed to get size of gamma for output default", you can try editing the usercfg.txt file located in the /boot/firmware directory. Add the necessary configuration for your desired resolution and restart your Raspberry Pi for the changes to take effect.

How can I open and edit the `usercfg.txt` file?

You can open and edit the usercfg.txt file by running the command sudo nano /boot/firmware/usercfg.txt in a terminal window. This will open the file in the nano text editor, where you can make the necessary changes.

How do I save changes and exit the nano text editor?

To save changes and exit the nano text editor, press Ctrl+O to write the file, then press Enter to confirm the filename. Finally, press Ctrl+X to exit the editor.

Do I need to backup any important files before changing the screen resolution?

It is always recommended to backup any important files before making changes to system configurations. This ensures that you can revert back to the previous state if anything goes wrong during the process.

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