Bug 513372

Summary:	On wayland, firefox playback stutters when interacting with the shell
Product:	[Plasma] plasmashell	Reporter:	Répási Dávid <hu.repasidavid>
Component:	generic-performance	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	kde
Priority:	NOR
Version First Reported In:	6.5.4
Target Milestone:	1.0
Platform:	EndeavourOS
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	system monitor output 2nd round

Description Répási Dávid 2025-12-14 18:36:08 UTC

SUMMARY

not a 6.5.4 issue, it's been here since 6 rolled around

be on wayland
have a twitch or youtube video playing in firefox (librewolf), will probably work with other sites
do any of the following action: open kickoff (with meta or click), scroll through the apps (switch between them), open the system tray, alt tab
any of those actions makes the video playback stutter (audio keeps playing, doesn't affect PIP)

EXPECTED RESULT

As on the x11 session, no stutters

SOFTWARE/OS VERSIONS
Linux: Linux 6.17.9-arch1-1 x86_64
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.21.0
Qt Version: 6.10.1
wayland: 1.24.0-1
xorg-server 21.1.21-1

Comment 1 David Edmundson 2025-12-15 13:54:52 UTC

Can you confirm if their is a spike in CPU during this time?

Comment 2 Répási Dávid 2025-12-15 16:42:29 UTC

Created attachment 187676 [details]
system monitor output

in both cases I scrolled the taskbar and opened kickoff with meta, both remained the same-ish between the two activities, with x11 spiking way more compared to wayland, but the playback didn't lag on it

the lags / stutters last half a second to a whole second

(disregard the gpu section, it's bugged on my hardware, thought it could give extra info)

Comment 3 Répási Dávid 2025-12-15 17:13:57 UTC

Created attachment 187679 [details]
2nd round

2nd round doing the same, this time the gpu graph decided to work, but only on X11, plus this time same apps open, my bad for the first one

Comment 4 Bug Janitor Service 2025-12-30 03:46:48 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

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

Comment 5 Répási Dávid 2025-12-30 13:24:20 UTC

Not a wayland/kwin issue. Tested on a fresh account both on x and w, neither lagged, tested on my main user account with a different firefox based browser under wayland, didn't lag. Must be a config problem in librewolf.

Comment 6 Bug Janitor Service 2026-01-14 03:47:21 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

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

Comment 7 Bug Janitor Service 2026-01-29 03:49:57 UTC

🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.