NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
Sorry, don't know if I should debug kscreen/kwin or not, but I tried to run qt python application in debug mode with no luck (it just shows exit code 1)
After monitor wake up literally every qt app is freezing for a few seconds then crashing when I do some input to them. Gtk apps aren't affected
STEPS TO REPRODUCE
1. Set monitor to switch off after 1 minute
2. Open some qt apps like dolphin or system settings
2. Let monitor sleep
3. Wake up
All qt apps crashed
(available in About System)
KDE Plasma Version: KDE 5.23.5
KDE Frameworks Version: 5.90
Qt Version: 5.15.2
Single 2560x1440 144hz monitor, wayland only, amd gpu (rx470)
Created attachment 145333 [details]
Video recording (obs source freezed after screen dimming)
I have the exact same issue.
Not all Qt apps are affected though, VLC for example is still responsive after the monitor wakes up.
It looks like only KDE apps are affected.
Can you get the backtrace of a crashing app? Also could you please capture the output of such an app while it runs with the WAYLAND_DEBUG=1 environment variable set? it may require ssh'ing from another computer
Created attachment 146484 [details]
Dolphin output with WAYLAND_DEBUG=1
Here is the output of Dolphin 21.12.2 with the WAYLAND_DEBUG=1 environment variable set, after turning off then on a DisplayPort monitor.
The output is very large, I suppose it starts to be relevant at line 1018: "qt.qpa.wayland: Creating a fake screen in order for Qt not to crash"
GPU: AMD RX560 (with Mesa 21.3.5)
Plasma version: 5.24.0
Frameworks version: 5.90.0
Created attachment 146485 [details]
KDE apps such as Dolphin, Yakuake (when it is visible) or System Settings, etc. no longer seem to crash, but they become unresponsive for a while after the screen wakes up (the window is greyed out, as in the screenshot attached).
After a minute or so the applications can be used normally again.
I am having the same issue. Freeze of kde apps, Konsole and Kontact mainly as they are often visible but no crash for me.
GPU: AMD RX 5700 XT (with Mesa 21.3.6)
Plasma version: 5.23.5/5.24.0/5.24.1
Frameworks version: 5.90.0/5.90/5.91
Distribution: Fedora 35
On another laptop I don't experience that. It has an Intel gpu, maybe it is linked.
Where I have the issue, I also have steam installed with all the i686 dependencies. Maybe linked too...
Tell me if I can help with debugging
It looks like it's fixed on my end now!
It may be related to the Plasma 5.24.3 or Qt 5.15.3 updates.
(In reply to Yannick from comment #7)
> It looks like it's fixed on my end now!
> It may be related to the Plasma 5.24.3 or Qt 5.15.3 updates.
It must be the QT 5.15.3 patch that fixes the issue. In fedora, the patch hasn't landed and with plasma 5.24.3 and qt 5.15.2, I still have the issue.
Waiting for the qt patch to land :)
*** Bug 450679 has been marked as a duplicate of this bug. ***
Looks like Debian unstable / testing is *finally* getting newer Qt, so this nasty bug will hopefully be fixed:
Debian testing finally after a huge wait got a newer Qt (5.15.4) and this bug is gone!