Fix Xubuntu Freezing When Locking Screen

lock-screenxfcexubuntu

Since I upgraded to Xubuntu 16.04 every time I lock the screen I get a black screen (with a white dash cursor in the top left corner) and there's nothing I can do to unlock it (I've tried Ctrl–Alt–F1 and Ctrl–Alt–F7 but nothing happens), except hard reboot.

Do you have suggestions to solve (or debug) this issue ?

Best Answer

To debug

  • Install accountsservice and xserver-xephyr, where:
    • accountsservice for Enhanced user accounts handling.
    • xserver-xephyr for LightDM test mode.

Then run LightDM as an X application for debugging: lightdm --test-mode --debug

  • LightDM's log file is /var/log/lightdm/lightdm.log, you will need root privilege to view it.
  • Or see output of dmesg with sudo dmesg.

List of workaround methods

  • Try to suspend and resume again

    Press CtrlAltF1, then login and type systemctl suspend. Press power button to resume and switch to tty7 by CtrlAltF7. In my case, I did 2 times to escape the blank screen.

  • Use DRI2 instead of DRI3 may solve the problem: https://wiki.archlinux.org/index.php/intel_graphics#DRI3_issues

  • Disable at-spi-dbus-bus.desktop (may NOT work)

    sudo mv -v -i /etc/xdg/autostart/at-spi-dbus-bus.desktop /etc/xdg/autostart/at-spi-dbus-bus.desktop.disabled

  • Replace light-locker with xscreensaver, then reboot.

References:

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