The screen goes black when I lock the system. LightDM Greeter is not displayed, but I can still type my password and unlock the system. Recently I found a workaround for this is to switch to the TTY of the desktop session ((Ctrl+Alt+F7 on my system), which makes LightDM Greeter to appear.

Why do I need to explicitly switch to TTY7 before login screen is displayed? Can login screen be displayed automatically?

  • 1
    Did you try to light up the screen before login using the screen brightness keys? – xenoid Aug 25 at 23:08
  • After locking, my display briefly says "No USB Type-C signal from your device", then it says "Entering power save mode" and blacks out. When I click any buttons on my screen, it displays the "No USB Type-C signal from your device" message again with longer text below saying to press keys to wake up the connected device. This is coming from the display itself. Pressing just any keys does not make the greeter to show up. Ctrl+Alt+F7 will show the greeter. Typing my password and pressing Enter straight up unlocks the laptop bypassing the greeter(?). – Dmytro Kyrychuk Aug 26 at 20:25
  • When external display is disconnected, the system behaves the same. The keyboard backlight turns on when I start typing, but the screen remains black until I type the entire password or switch to TTY7 explicitly. – Dmytro Kyrychuk Aug 26 at 20:30

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