Linux Autostart: X11 or KMS

First finish Linux Installation and verify capture manually. Choose one startup method for the account. These examples use ~/Applications/VoidVideo; adjust every path if you installed elsewhere.

X11 is the desktop session used in this guide. KMS means running Void Video directly on the display without loading the desktop. You can stay with the desktop option; the second option is for a dedicated processor PC.

When a step opens the nano text editor, paste the supplied text, press Ctrl+O, then Enter to save, and Ctrl+X to exit.

Method	When it starts	Best for
Desktop (X11)	After desktop login	A PC where you also use KDE and other applications.
Direct display (KMS)	After text login, or automatically at boot	A dedicated Void Video PC that runs without the desktop.

Start with the desktop option. If you want the PC to boot straight into Void Video without loading KDE, use the direct-display steps below. First check that you get a picture and that your keyboard controls work.

Test X11 manually

At the login screen, select Plasma (X11) for KDE or Xfce Session for XFCE. On Debian 13, if the X11 session is unavailable, install kwin-x11 and xserver-xorg, then log out and check the session selector again. Debian KWin X11 package

In Konsole (KDE) or Terminal (XFCE):

printf '%s\n' "$XDG_SESSION_TYPE"
cd "$HOME/Applications/VoidVideo"
SDL_VIDEO_DRIVER=x11 ./VoidVideo -f --log

The first command should print x11. If it prints something else, log out and choose Plasma (X11) or Xfce Session before continuing.

Verify capture and quit with F9. Disable display sleep/locking in your desktop’s power-management settings if this machine must play unattended. Check that the picture uses your intended resolution and refresh rate.

Start automatically after desktop login

Create the autostart entry:

mkdir -p "$HOME/.config/autostart"
nano "$HOME/.config/autostart/voidvideo.desktop"

Paste the following, replacing both /home/YOUR_USER paths with your actual home directory. Use the full paths shown, with your username in place of YOUR_USER.

[Desktop Entry]
Type=Application
Name=Void Video
Exec=env SDL_VIDEO_DRIVER=x11 /home/YOUR_USER/Applications/VoidVideo/VoidVideo -f --log
Path=/home/YOUR_USER/Applications/VoidVideo
Terminal=false

The path shown assumes a username/install path without spaces. Keep the installation in the simple path used by this guide. Log out and back into Plasma (X11) or Xfce Session to test. It should launch once, fullscreen, with logs in the same application directory. This uses the standard desktop autostart mechanism.

This starts after login, not before it. For a dedicated PC, KDE's SDDM login-screen settings can enable automatic login for the chosen user and X11 session. Automatic login lets someone with physical access use that account.

To disable application autostart, rename the file:

mv "$HOME/.config/autostart/voidvideo.desktop" "$HOME/.config/autostart/voidvideo.desktop.disabled"

Test direct KMS from a local console

Use the keyboard connected to the Void Video PC for these steps. This mode runs without KDE, so save your work before closing the desktop.

1. Save desktop work and quit Void Video.

2. Press Ctrl+Alt+F3 to open a text console and log in as your normal user.

3. Stop the desktop login manager. This terminates graphical sessions, so run it only after saving your work:

   sudo systemctl stop display-manager

4. Start direct output:

   cd "$HOME/Applications/VoidVideo"
   SDL_VIDEO_DRIVER=kmsdrm ./VoidVideo -f --log

5. Check the picture, keyboard controls, resolution, and refresh rate. Quit with F9.

6. Return to the graphical login screen when finished:

   sudo systemctl start display-manager

This only closes the desktop for the current session. Restarting the PC will still bring back the normal login screen.

If no picture appears

• Make sure you followed the steps at the PC itself and closed the desktop first.
• Check that the projector or monitor is connected to the graphics card you intend to use.
• For NVIDIA, complete the driver checks.
• Press F9, then use the command above to return to the desktop. Keep logs/voidvideo.txt from the Void Video folder when asking for help.

Continue using desktop mode until direct output works. Set up automatic startup only after the manual test succeeds.

Start KMS after console login

After the manual KMS test succeeds, configure one console to launch it. This example uses tty1, leaving other consoles for maintenance.

For Debian's default Bash account, edit ~/.profile. If ~/.bash_profile or ~/.bash_login already exists, Bash may use it instead; put the block in the login file actually read by that account. Preserve its existing contents.

Add this at the end:

# Start Void Video only from the local tty1 login, outside a desktop.
if [ -z "${DISPLAY:-}" ] && [ -z "${WAYLAND_DISPLAY:-}" ] && [ "$(tty)" = /dev/tty1 ]; then
    (
        cd "$HOME/Applications/VoidVideo" || exit
        SDL_VIDEO_DRIVER=kmsdrm ./VoidVideo -f --log
    )
fi

F9 returns you to the text prompt. Void Video will not immediately reopen. Other consoles remain available for maintenance.

To show the text login at startup instead of KDE:

sudo systemctl set-default multi-user.target
sudo reboot

Log in on tty1 and confirm that Void Video starts. If necessary, press Ctrl+Alt+F1 to select it. KDE remains installed, and you can restore desktop startup using the steps at the end of this page.

Optional: automatic KMS login at boot

Only do this after the tty1 login launch works. It bypasses the password prompt for the selected local account, including when Void Video exits back to the shell.

Run:

sudo systemctl edit [email protected]

Add this override, replacing YOUR_USER with the normal account used for Void Video:

[Service]
ExecStart=
ExecStart=-/sbin/agetty --autologin YOUR_USER --noclear %I $TERM

Then:

sudo systemctl daemon-reload
sudo systemctl enable [email protected]
sudo reboot

After restarting, Void Video should open automatically. Pressing F9 returns to the text prompt.

If startup fails, keep ~/Applications/VoidVideo/logs/voidvideo.txt when asking for help. Use the steps below to restore the desktop.

Undo KMS autostart

From another console, such as Ctrl+Alt+F3, log in and:

1. Remove the Void Video block from your login profile.

2. If you added automatic login, use sudo systemctl edit [email protected] and remove the ExecStart override added above. Preserve any unrelated overrides.

3. Restore desktop boot:

   sudo systemctl daemon-reload
   sudo systemctl set-default graphical.target
   sudo reboot

At the next boot, the normal graphical login should return. Do not leave both desktop autostart and console autostart enabled for the same application while switching methods.