Bug 1943522

Since Fedora 34 is making Wayland for KDE sessions default, this bugs started to affect Fedora 34 KDE spin.

Steps to reproduce:
1. Boot a desktop machine from the Fedora 34 beta KDE spin USB stick.
2. Wait for 10 minutes for the attached monitor to enter power save mode.
3. kwin_wayland will crash.

I have been waiting long for KDE to use Wayland on Fedora by default, but this is a stopper for me.

+++ This bug was initially created as a clone of Bug #1705121 +++

Description of problem:
Whenever the system has no connected monitor kwin_wayland segfaults. For example it is triggered when:
- all the monitors are plugged off
- the existing monitors are put into sleep mode by plasma
- the monitors are turned off (this is not reproducible with all my monitors just with one)

If you have two or more monitors applying the previous steps to all but one monitor does not lead to the crash.

Version-Release number of selected component (if applicable): 5.15.4


How reproducible: always


Steps to Reproduce:
1. Start a wayland plasma session
2. Unplug all the monitors
3. Plug back at least one monitor

Actual results: kwin segfaults and you are greeted with a black screen. The system is also not in a recoverable state (can't access any tty to restart plasma or take any action) the only option is to forcefully reboot it.


Expected results: kwin should not segfault


Additional info: 
Mesa 19.0.3-1
Plasma 5.15.4
KF5 5.57.0-2 (but reproducible also with 5.55 which is the current stable)
kernel 5.0.9-301
wayland 1.17.0-1

Graphic card: AMD Radeon RX 580

The attached systemd logs were reproduced with a single monitor which has then been unplugged leading to the segfault (note the part that says "requesting unexisting screen -1"):

May 01 16:14:27 localhost.localdomain kernel: Code: 00 00 d0 ef 05 4e 7f 7f 00 00 80 eb 05 4e 7f 7f 00 00 40 eb 05 4e 7f 7f 00 00 00 00 00 00 00 00 00 00 51 00 00 00 00 00 00 00 <c0> 6b f1 90 58 55 00 00 00 00 00 00 00 00 00 00 00 12 4c 91 58 55
May 01 16:14:27 localhost.localdomain kernel: kwin_wayland[1884]: segfault at 555891595120 ip 0000555891595120 sp 00007ffc72288f98 error 15
May 01 16:14:27 localhost.localdomain audit[1884]: ANOM_ABEND auid=1000 uid=1000 gid=1000 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 pid=1884 comm="kwin_wayland" exe="/usr/bin/kwin_wayland" sig=11 res=1
May 01 16:14:27 localhost.localdomain plasmashell[2063]: requesting unexisting screen -1
May 01 16:14:27 localhost.localdomain plasmashell[2063]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/views/Desktop.qml:146:19: QML Loader: Binding loop detected for property "height"
May 01 16:14:27 localhost.localdomain plasmashell[2063]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/views/Desktop.qml:146:19: QML Loader: Binding loop detected for property "height"
May 01 16:14:27 localhost.localdomain plasmashell[2063]: trying to show an empty dialog
May 01 16:14:27 localhost.localdomain plasmashell[2063]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()

Let me know if you need anything else.
Thanks

--- Additional comment from Ben Cotton on 2020-04-30 22:10:36 UTC ---

This message is a reminder that Fedora 30 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 30 on 2020-05-26.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
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Although we aim to fix as many bugs as possible during every release's 
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--- Additional comment from Ben Cotton on 2020-05-26 14:56:12 UTC ---

Fedora 30 changed to end-of-life (EOL) status on 2020-05-26. Fedora 30 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
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