Hi, xfwm4 user? Try the following and restart xfwm4: xfconf-query -c xfwm4 -p /general/vblank_mode -s xpresent
Long description: Issue can be sometimes reproduced by starting glxgears and locking the screen. After unlocking, the screen stays black with a visible and movable mouse cursor. The issue isn't related to lightdm or light-locker. It also occurs with slim as display manager and with xscreensaver or xsecurelock/xss-lock. It is related to the auto and glx vblank setting of the xfwm4 window manager which is unfortunately the default. Possibly in combination with (older) Intel graphics cards. Workaround is to disable vblank or use xpresent which can be done with one of the following lines: xfconf-query -c xfwm4 -p /general/vblank_mode -s xpresent xfconf-query -c xfwm4 -p /general/vblank_mode -s off xfwm4 must be restarted for the change to take effect. It took me forever to figure that out. Best regards, Andreas
