Bug 462759

Summary:	[NVIDIA] On Wayland, external monitors cause system to be unusably laggy
Product:	[Plasma] kwin	Reporter:	fake.name
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	major	CC:	fake.name, nate, xaver.hugl
Priority:	NOR
Version First Reported In:	5.26.4
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description fake.name 2022-12-07 23:21:22 UTC

SUMMARY
When connecting to an external monitor via HDMI on Wayland, the entire system will become laggy to the point that the use of the monitor is not possible; in addition to the lag, movement is choppy, such that cursors, windows, etc seem to teleport from place to place, rather than traveling smoothly across the screen.

This is plasma/kwin specific -- things are working fine on hyprland, for example.

Placing under unknown location since I'm not sure if this is kwin or kscreen.

STEPS TO REPRODUCE
1. Begin Wayland session
2. Plug in external monitor
3. Observe the crippled system

OBSERVED RESULT
If an external monitor is plugged in, the system immediately becomes laggy and choppy visually such that use is untenable.

EXPECTED RESULT
The external monitor should not impede system responsiveness.

SOFTWARE/OS VERSIONS
Linux: Arch, running Zen 6.0.11
KDE Plasma Version: 5.26.4
KDE Frameworks Version: 5.100.0
Qt Version: 5.15.7

ADDITIONAL INFORMATION
The system has an NVIDIA rtx 3060 connected to the HDMI out. Both the external monitor and the internal monitor of the laptop are 4k screens with a 60 Hz refresh rate set to scale identically. Graphics are meant to be handled primarily by an intel iGPU.

Drivers are:
nvidia-dkms 525.60.11
mesa-22.2.3-1

Comment 1 Nate Graham 2023-01-03 19:38:18 UTC

Does it happen in the Plasma X11 session too?

Comment 2 fake.name 2023-01-03 20:20:41 UTC

(In reply to Nate Graham from comment #1)
> Does it happen in the Plasma X11 session too?
Short answer no;

Long answer, not in such absolute terms. Multi-monitor on X11 isn't hassle free for me; a similar bug happens only if set to only use the external monitor, but in that case the cursor doesn't lag (and the rest of the lag is worse).

Comment 3 Nate Graham 2023-01-04 17:40:54 UTC

Thanks.

Comment 4 Zamundaaa 2023-01-06 13:20:05 UTC


*** This bug has been marked as a duplicate of bug 452219 ***