Bug 394890 - Compositing disabled on external monitor connection if background contrast effect is disabled
Summary: Compositing disabled on external monitor connection if background contrast ef...
Alias: None
Product: kwin
Classification: Unclassified
Component: compositing (show other bugs)
Version: 5.21.5
Platform: Neon Packages Linux
: NOR normal with 3 votes (vote)
Target Milestone: ---
Assignee: KWin default assignee
Keywords: reproducible, usability
Depends on:
Reported: 2018-05-31 11:21 UTC by Ivan Safonov
Modified: 2021-07-24 18:21 UTC (History)
13 users (show)

See Also:
Latest Commit:
Version Fixed In:

kwinrc (1.44 KB, text/plain)
2018-05-31 11:21 UTC, Ivan Safonov
screenshot (307.25 KB, image/png)
2018-05-31 11:23 UTC, Ivan Safonov
disabled Allow applications to block compositing (324.69 KB, image/png)
2018-05-31 12:14 UTC, Ivan Safonov
attachment-22042-0.html (62 bytes, text/html)
2021-01-26 14:21 UTC, jan.claussen10
kwin logs (15.60 KB, text/plain)
2021-06-11 16:08 UTC, nicode25

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Description Ivan Safonov 2018-05-31 11:21:56 UTC
Created attachment 112980 [details]

How to reproduce

1) Disable "Background contrast" desktop effect
2) Connect or disconnect external monitor

I reproduced this bug on two different machines, brand new Dell Latitude and 4 years old Samsung ATIV 5. On both of them installed KDE neon 5.12.5. If "Background contrast" desktop effect is enabled everything works just fine.
Comment 1 Ivan Safonov 2018-05-31 11:23:12 UTC
Created attachment 112981 [details]
Comment 2 Martin Flöser 2018-05-31 11:25:45 UTC
The notification you screenshot shows that an application blocks compositing. You can disable this feature in the settings. It has nothing to do with the background contrast or multiple screens.
Comment 3 Ivan Safonov 2018-05-31 12:14:07 UTC
>> You can disable this feature in the settings?

What feature? "Allow applications to block compositing"?
I disabled it and on the next monitor connection it happened again.
Comment 4 Ivan Safonov 2018-05-31 12:14:59 UTC
Created attachment 112983 [details]
disabled Allow applications to block compositing
Comment 5 Ivan Safonov 2018-05-31 12:18:15 UTC
And what application can block compositing? Can I find it somewhere in logs?
Comment 6 Piotr Keplicz 2019-11-12 13:14:54 UTC
Similar bug here on KDE neon 5.17.2. Attaching a secondary screen disables compositing when "Background contrast" is disabled. 

After I enabled this effect, compositing is no longer disabled on secondary display status change.
Comment 7 Vlad Zahorodnii 2019-11-21 14:10:08 UTC
@Piotr Is compositing blocked in your case too?
Comment 8 Piotr Keplicz 2019-11-21 14:30:36 UTC
"Allow applications to block compositing" is enabled in my case.
Comment 9 Vlad Zahorodnii 2019-11-21 14:32:09 UTC
Try to disable the feature and see if the problems happens again.
Comment 10 Vlad Zahorodnii 2019-11-21 14:32:23 UTC
Comment 11 beojan 2020-05-24 20:10:30 UTC
I'm experiencing the same issue with kwin_x11 5.18.5. It persists even with "Allow applications to block compositing" switched off.
Comment 12 Val L. 2020-06-02 04:33:17 UTC
Happening to mine as well. Even with Background contrast enabled or Allow applications to block compositing is disabled everytime I attach a secondary display compositing is blocked

I'm using an optimus laptop which is a Dell XPS 15 7590 and the Nvidia GPU enabled. Using Plasma 5.18.5 on Manjaro 20.0.2.

This didn't happen I believe before 5.18 but not entirely sure.
Comment 13 Rich Grundy 2020-07-01 06:49:21 UTC
Can confirm with "background contrast" disabled I also receive the same issue. Turning on or off "Allow applications to block compositing" has no affect.

KDE: 5.19.2
KDE Framework: 5.71.0
QT: 5.15.0
Kernel: 5.7.6

GPU: Radeon RX570 with amdgpu
Comment 14 jan.claussen10 2020-07-01 13:20:22 UTC
I have this bug too. Disabling „Let applications block compositing“ doesn’t change anything. I just started recently though. Like about one month ago.
Comment 15 jan.claussen10 2020-07-01 13:26:28 UTC
@Rich Grundy: Are you on Manjaro too?
Comment 16 Rich Grundy 2020-07-01 14:06:47 UTC
(In reply to jan.claussen10 from comment #15)
> @Rich Grundy: Are you on Manjaro too?

Arch standard, so kinda.
Comment 17 Andreas Korb 2021-01-24 23:20:15 UTC
I'm on Manjaro with KDE 5.20.5 and experience the same. I also have this problem after my screen went to sleep. With enabled "Background contrast" desktop effect the problem is gone.

I execute `kwin_x11 --replace &` each time after it happens to restore compositing.

I'm using proprietary Nvidia drivers.
Comment 18 Julius R. 2021-01-26 14:19:58 UTC
Same problem here. This is critical for everyday usage, it is a bit strange, that it has not been adressed as priority.
Comment 19 jan.claussen10 2021-01-26 14:21:22 UTC
Created attachment 135209 [details]

Yeah, hasn't been fixed for almost a year now..
Comment 20 Sven 2021-04-09 08:43:53 UTC
Same problem connecting/disconnecting monitors with KDE plasma 5.21.3 (frameworks 5.80.0), Manjaro 21.0. But also encountered the issue with 5.20.

Desktops effects get suspended and can easily be re-enabled with alt+shift+f12, but it is annoying. Enabling "background contrast" fixes the problem for some reason.
Comment 21 slayer5934 2021-06-01 03:31:19 UTC
Still an issue 2 years later, this is super annoying to new users and usability I can tell you that much.
Comment 22 Vlad Zahorodnii 2021-06-07 07:03:27 UTC
Can somebody try to reproduce the issue and post kwin's output? Please run kwin as follows

   env QT_LOGGING_RULES="kwin_scene_opengl.debug="true" kwin_x11 --replace
Comment 23 slayer5934 2021-06-08 03:00:54 UTC
(In reply to Vlad Zahorodnii from comment #22)
> Can somebody try to reproduce the issue and post kwin's output? Please run
> kwin as follows
>    env QT_LOGGING_RULES="kwin_scene_opengl.debug="true" kwin_x11 --replace

I did this command but I can't find the logs.
Comment 24 nicode25 2021-06-11 16:08:46 UTC
Created attachment 139233 [details]
kwin logs

I am only able to reproduce this bug when booting connected with an external screen.
(KDE neon 5.22)
Here are the logs with journalctl with QT_LOGGING_RULES="kwin_*.debug=true"

(line 79) kwin_scene_opengl: Suspending compositing because viewport limits are not met
Comment 25 Julius R. 2021-07-24 18:21:35 UTC
I am suffering from the same problem. This bug should get far more attention!