Bug 401540 - Windows moved to second monitor are snapped instead of dragged using multiple Xserver screens
Summary: Windows moved to second monitor are snapped instead of dragged using multiple...
Status: RESOLVED WORKSFORME
Alias: None
Product: kwin
Classification: Plasma
Component: multi-screen (show other bugs)
Version: 5.12.7
Platform: Ubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-11-29 16:14 UTC by Riccardo
Modified: 2023-02-18 03:47 UTC (History)
0 users

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Window is snapped, can't be dragged on the second monitor (1.72 MB, image/png)
2018-11-29 16:14 UTC, Riccardo
Details
supportInformation (5.85 KB, text/plain)
2018-11-29 19:38 UTC, Riccardo
Details

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Description Riccardo 2018-11-29 16:14:42 UTC
Created attachment 116567 [details]
Window is snapped, can't be dragged on the second monitor

SUMMARY
To activate coolbits and fan control on Nvidia card, one has to create a X screen for each GPU in the PC. Usually only the first X-screen is "real", and all the physical monitors are connected to a single video card. Doing so, with multiple video card and multiple screens attached to the same video card, window snapping goes crazy: moving a windows from one screen to the other cause the window to be snapped in the first monitor instead of being moved to the next monitor.

STEPS TO REPRODUCE
1. In a multi-GPU and multi-monitor environment, set Xserver like this: https://unix.stackexchange.com/questions/200553/multi-nvidia-gpu-overclocking-for-computations-cuda
2. Connect all the monitor to the first video card.
2. Settings > Desktop Behaviour > Screen Edges > Activate "Tile windows by dragging them to the left or right screen edges"
3. Drag a window and move to the next monitor.

OBSERVED RESULT
Window moved out of a main monitor will snap.


EXPECTED RESULT
Window moved out of a main monitor should not snap if the window is moved in the direction of another connected monitor.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 18.04 (with backports repo)
KDE Plasma Version: 5.12.7
KDE Frameworks Version: 5.47.0
Qt Version: 5.9.5

ADDITIONAL INFORMATION
It is also impossible to snap windows in the second monitor (both moving on top or on the border of the second monitor).
Also there is another bug could be related: with the current Xserver configurations, Meta key will not start the application menù, while ALT+F1 will do the job correctly.
Comment 1 Martin Flöser 2018-11-29 17:36:29 UTC
Please provide the output of qdbus org.kde.KWin /KWin supportInformation
Comment 2 Riccardo 2018-11-29 19:38:46 UTC
Created attachment 116571 [details]
supportInformation
Comment 3 Martin Flöser 2018-11-29 19:52:22 UTC
I'm sorry, but multi-head setups are not really supported. This is the first time in years that a bug regarding multi head is reported.

What you use in addition is multi screen on a multi head system. I wasn't even aware that this is possible. It's definitely not a feature we support. As X11 is feature frozen and this is a rather strong corner case setup I fear this will never get worked on.
Comment 4 Riccardo 2018-11-30 10:19:42 UTC
In my field (computer vision and machine learning) it's not so unusual to have two or more  GPU on a computer, and of course multiple screens.

I have no problems with other desktop environments (I have tried gnome and cinnamon).

Actually the root of the problem is Nvidia, because the only way to control the fan speed on linux on a graphic card is to have an X server running on that graphic card.

With that configuration I was trying to start an x-server to the second graphic only with the end to control it's fan speed, while using the first graphic card for the output on the screen.

The Destkop Envirnoment should just ignore the second x-server-screen, but kde plasma seems to have some problem and goes crazy.
Comment 5 Justin Zobel 2023-01-19 00:18:48 UTC
Thank you for reporting this issue in KDE software. As it has been a while since this issue was reported, can we please ask you to see if you can reproduce the issue with a recent software version?

If you can reproduce the issue, please change the status to "REPORTED" when replying. Thank you!
Comment 6 Bug Janitor Service 2023-02-03 05:01:37 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 7 Bug Janitor Service 2023-02-18 03:47:37 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!