Bug 478361

Summary:	Window previews spam log and introduce lag in task manager
Product:	[Plasma] kwin	Reporter:	markus.wallerberger
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	minor	CC:	fedramblo, markus.wallerberger, nate
Priority:	NOR	Keywords:	wayland-only
Version First Reported In:	5.27.10
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:	6.0
Sentry Crash Report:
Attachments:	Example of lag when moving the cursor over icons

Description markus.wallerberger 2023-12-10 18:58:36 UTC

SUMMARY
On Wayland and pipewire, using the standard Task Manager and having "show small window previews when hovering over tasks" enabled, the mouse starts lagging as soon as I hover over a task. At the same time, the pipewire starts spamming the syslog with the following warning messages:

Dec 10 19:40:42 hopper pipewire[1590]: mod.client-node: 0x56018f5de1a0: unknown peer 0x56018f6628b0 fd:126
Dec 10 19:40:43 hopper pipewire[1590]: mod.client-node: 0x56018f6803d0: unknown peer 0x56018f685a50 fd:69
Dec 10 19:40:45 hopper pipewire[1590]: mod.client-node: 0x56018f6528a0: unknown peer 0x56018f64fac0 fd:67
...

As a workaround, disabling this setting removes both the lag and the messages. 

STEPS TO REPRODUCE
1. Start a Wayland shell. Make sure you have pipewire active.
2. (if not already present) Add a task manager to some panel on Plasma.
3. In the task manager's settings, make sure "show small window previews when hovering over tasks" is enabled
4. Hover over some tasks

OBSERVED RESULT
1. Task manager lags slightly (mouse movement...)
2. Warning messages appear in syslog

EXPECTED RESULT
None of the above happening.

SOFTWARE/OS VERSIONS
Linux: 6.6.5
KDE Plasma Version: 5.27.10 
KDE Frameworks Version: 5.112.0
Qt Version: 5.15.11

Comment 1 Nate Graham 2023-12-12 17:20:37 UTC

I don't get any lag, but I do see some log spam. It's different for me though:

Dec 12 10:20:00 Liberator plasmashell[184703]: kpipewire_logging: PipeWire remote error:  -2 unknown resource 6 op:7
Dec 12 10:20:00 Liberator plasmashell[184703]: kpipewire_logging: PipeWire remote error:  -2 unknown resource 8 op:7
Dec 12 10:20:05 Liberator plasmashell[184703]: kpipewire_logging: PipeWire remote error:  -2 target not found
Dec 12 10:20:05 Liberator plasmashell[184703]: kpipewire_logging: PipeWire remote error:  -2 unknown resource 8 op:7

Are you using an NVIDIA GPU?

Comment 2 markus.wallerberger 2023-12-12 17:24:30 UTC

Hi Nate, no I have an integrated Intel card.  Here's what lshw has to say:

  *-display                 
       description: VGA compatible controller
       product: Raptor Lake-P [Iris Xe Graphics]
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       logical name: /dev/fb0
       version: 04
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
       configuration: depth=32 driver=i915 latency=0 mode=1920x1200 resolution=1920,1200 visual=truecolor xres=1920 yres=1200
       resources: iomemory:600-5ff iomemory:400-3ff irq:140 memory:603c000000-603cffffff memory:4000000000-400fffffff ioport:2000(size=64) memory:c0000-dffff memory:4010000000-4016ffffff memory:4020000000-40ffffffff

Comment 3 decker23 2023-12-13 12:13:41 UTC

Created attachment 164129 [details]
Example of lag when moving the cursor over icons

Comment 4 decker23 2023-12-13 12:17:36 UTC

Comment on attachment 164129 [details]
Example of lag when moving the cursor over icons

I am experiencing the same problem on Fedora 39 (Kernel 6.6.4, KDE 5.27.9, Wayland, Intel HD Graphics 5300). I was about to create a new bug, but I noticed this one.

With the "show small window previews when hovering over tasks" option enabled, when moving the cursor over the taskbar, it breaks on some icons. It looks terrible. And indeed, on the journalctl -e command I see messages like:
pipewire[2002]: mod.client-node: 0x559b4d35e1e0: unknown peer 0x559b4d54e100 fd:111
(but I don't know if it's related to the bug)

Comment 5 Nate Graham 2023-12-13 22:00:10 UTC

Ahh, this. It's already fixed in Plasma 6.