SUMMARY Sometimes, when I (in quick succession) unplug the external screen and suspend my laptop by closing the lid, when I resume the laptop, the internal screen is just black. This is a critical bug that leads to data loss because I have to hard-kill the KDE session. STEPS TO REPRODUCE 1. Have an external screen connected and but the desktop exclusively there (so the internal screen is disabled). 2. Unplug the screen and suspend the machine in quick succession. Unfortunately I have not found a way to reproduce this. 3. Resume the machine. OBSERVED RESULT The internal screen comes back black. EXPECTED RESULT The internal screen should be enabled properly when coming back from suspend. SOFTWARE/OS VERSIONS Operating System: Debian GNU/Linux 10 KDE Plasma Version: 5.14.5 Qt Version: 5.11.3 KDE Frameworks Version: 5.54.0 Kernel Version: 4.19.0-5-amd64 OS Type: 64-bit ADDITIONAL INFORMATION Connecting an external screen to HDMI shows that the image is still on that port. But of course when I am traveling at that point, I don't usually have an external screen in my luggage... Ctrl-Alt-Fn still switches to a normal terminal session, but switching back to X11 does not fix the issue. I can blindly unlock the screen, open a terminal and type "touch xx" to see (in the terminal) that this actually happens. But I found no way to enable the screen so far. I tried "xrandr -q". ("xbacklight" does not work at all on my laptop so I couldn't try that.) I have used Gnome on this laptop for a year and this has not happened a single time. Hence I think that this is an issue in KDE, not in the drivers.
Do you have a cursor on the black screen? >Ctrl-Alt-Fn still switches to a normal terminal session, Please do this and then run DISPLAY=:0 xrandr -q (or DISPLAY=:0 xrandr -q > someLogFile)
> Do you have a cursor on the black screen? No, if I recall correctly the screen is black as if it was just turned off. (Which is why I tried "xbacklight", I remember that helping in a similar situation several years ago on another machine. Seems like I need to figure out which command I have to use for that nowadays.) > Please do this and then run I will try that next time it happens.
This happened again and I captured the output of "DISPLAY=:0 xrandr -q": Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192 eDP-1 connected (normal left inverted right x axis y axis) 3840x2160 60.00 + 59.98 59.97 3200x1800 59.96 59.94 2880x1620 59.96 59.97 2560x1600 59.99 59.97 2560x1440 59.99 59.99 59.96 59.95 2048x1536 60.00 1920x1440 60.00 1856x1392 60.01 1792x1344 60.01 2048x1152 59.99 59.98 59.90 59.91 1920x1200 59.88 59.95 1920x1080 60.01 59.97 59.96 59.93 1600x1200 60.00 1680x1050 59.95 59.88 1600x1024 60.17 1400x1050 59.98 1600x900 59.99 59.94 59.95 59.82 1280x1024 60.02 1440x900 59.89 1400x900 59.96 59.88 1280x960 60.00 1440x810 60.00 59.97 1368x768 59.88 59.85 1360x768 59.80 59.96 1280x800 59.99 59.97 59.81 59.91 1152x864 60.00 1280x720 60.00 59.99 59.86 59.74 1024x768 60.04 60.00 960x720 60.00 928x696 60.05 896x672 60.01 1024x576 59.95 59.96 59.90 59.82 960x600 59.93 60.00 960x540 59.96 59.99 59.63 59.82 800x600 60.00 60.32 56.25 840x525 60.01 59.88 864x486 59.92 59.57 800x512 60.17 700x525 59.98 800x450 59.95 59.82 640x512 60.02 720x450 59.89 700x450 59.96 59.88 640x480 60.00 59.94 720x405 59.51 58.99 684x384 59.88 59.85 680x384 59.80 59.96 640x400 59.88 59.98 576x432 60.06 640x360 59.86 59.83 59.84 59.32 512x384 60.00 512x288 60.00 59.92 480x270 59.63 59.82 400x300 60.32 56.34 432x243 59.92 59.57 320x240 60.05 360x202 59.51 59.13 320x180 59.84 59.32 DP-1-1 disconnected (normal left inverted right x axis y axis) DP-1-2 disconnected (normal left inverted right x axis y axis) DP-1-3 disconnected (normal left inverted right x axis y axis) I also, for the first time, managed to get the machine out of this state without restart my session, by blindly typing "xrandr --auto" on a terminal. (Doing "DISPLAY=:0 xrandr --auto" on another terminal did not work.)
This is mostl likely fixed with https://phabricator.kde.org/R104:e47dc21a7b7824889171f01bdc4b0209c8b1fed6 in Plasma 5.17.1