Display does not turn off on idle or lock- blank with backlight on

User Support General
1

Unsure if there’s some other setting I’m not aware about, hence why the forum question rather than a github issue.

Qubes OS release
4.1

Brief summary
I have set the screensaver to lock my screen after 2 minutes of inactivity but the display is never actually off: rather, it displays a black background but the backlight is still on.
I have tried setting the screensaver mode to “Blank Screen Only” and checked “Lock Screen After 0 minutes”. I have also tried setting the screensaver mode to “Disable Screen Saver”.

Steps to reproduce

  1. Open Screensaver settings
  2. Set mode to “Blank Screen Only”
  3. Set a “Blank After timer” and select “Lock screen After”
  4. Wait out the timer or lock the screen manually
  5. Observe that the backlight is still on, with a black background shown

Expected behavior
When the screen locks, the display should turn off completely.

Actual behavior
When the screen locks, the display goes blank but the backlight is still on.

2
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3

This issue can be resolved by enabling Display Power Management under Advanced tab of ‘Screensaver Preferences’. The application is located under System tools -> Screensaver under the default XFCE desktop environment or /usr/bin/xscreensaver-demo in dom0; odd binary name.

That being said, I did run into a strange bug where one of the monitors only turns off for ~5 seconds before going to the blank screen with backlight active, additionally the configuration for that monitor is lost and after logging back in, the monitor is in mirror mode.

My setup is as follows:

  • AMD Radeon RX580
  • 1x DP 1920x1080@60 extended (1.) (this one loses the configuration and remains active)
  • 1x DVI 1920x1080@144 extended (2.)
  • 1x DP 1920x1080@60 extended (3.)
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