Bug 448981

SUMMARY

STEPS TO REPRODUCE
1. Wait for "Screen Energy Saving" to trigger standby or `sleep 1; xset dpms force off` (or force standby or force suspend)
2. wait about 10 seconds for monitors to fully go into standby mode
3. press any key

OBSERVED RESULT
The secondary monitor resumes about 2 seconds after the primary monitor.  All of the windows briefly show up on the secondary monitor, then once the primary monitor resumes the windows go back to the respective monitors they were on before the monitors enter standby mode, but they are all on either the right edge or left edge of the respective monitors.
In addition, the Audio Device Profile output gets reset to the secondary monitor.

EXPECTED RESULT
Window positions and Audio Device Profile should remain the same as they were before the monitors entered standby mode.

SOFTWARE/OS VERSIONS
Operating System: Debian GNU/Linux 11 unstable
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.88.0
Qt Version: 5.15.2
Kernel Version: 5.15.0-3-amd64 (64-bit)
Graphics Platform: X11
Processors: 48 × Intel® Xeon® CPU E5-2697 v2 @ 2.70GHz
Memory: 503.9 GiB of RAM
Graphics Processor: AMD Radeon RX 580 Series

ADDITIONAL INFORMATION
If I make the primary monitor the secondary and vice versa, the window placement issue remains but the audio profile issue is resolved.

It seems like the best way to resolve this is to allow some delay before the windows are placed and the audio profile is set.  Perhaps there is an setting for this somewhere?  Thanks.

$ xrandr -q
Screen 0: minimum 320 x 200, current 5280 x 2560, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 connected primary 3840x2160+0+400 (normal left inverted right x axis y axis) 698mm x 393mm
   3840x2160     60.00*+  60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   2560x1440     59.95  
   1920x1200     60.00  
   1920x1080     60.00    50.00    59.94  
   1600x1200     60.00  
   1680x1050     59.95  
   1280x1024     60.02  
   1440x900      59.89  
   1280x960      60.00  
   1280x800      59.81  
   1280x720      60.00    50.00    59.94  
   1024x768      60.00  
   800x600       60.32    56.25  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       60.00    59.94  
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
HDMI-A-1 connected 1440x2560+3840+0 left (normal left inverted right x axis y axis) 597mm x 336mm
   2560x1440     59.95*+
   1920x1200     59.95  
   1920x1080     60.00    50.00    59.94  
   1600x1200     59.95  
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1440x900      59.95  
   1280x800      59.91  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    60.00  
   832x624       74.55  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
DVI-D-0 disconnected (normal left inverted right x axis y axis)