The Blank Display
By default, Ubuntu is configured to save power and secure your system when you step away. If the operating system detects no mouse movement or keyboard input for a specific period (usually 5 minutes), it automatically activates the screen saver. In modern Ubuntu (GNOME), this usually means simply blanking the screen completely to black to save monitor power, followed shortly by locking the session. While this is secure for an office environment, it is incredibly annoying if you are using Ubuntu to monitor a dashboard, compile code on a secondary monitor, or watch a long video through a non-native media player that fails to block the idle timer.
Keeping the Screen Alive
To ensure your monitor stays illuminated and stop Ubuntu from automatically activating the screen saver and blanking the display, you must disable the screen blanking timeout in the power settings.
Open the primary system settings by clicking the network/volume cluster in the top-right corner of the top panel and selecting Settings (the gear icon). In the left-hand sidebar, click on Power (you may need to scroll down to find it). Look at the right-hand panel under the “Power Saving” section for an option labelled Screen Blank. This will likely be set to a specific time, such as “5 minutes.” Click on the dropdown menu and select Never. Note: If you also want to ensure the screen doesn’t lock when it blanks, you must go to the Privacy tab on the left, select Screen Lock, and ensure “Automatic Screen Lock” is toggled Off.