Bug 510314

Summary:	mpv resize is super slow with radv driver on wayland
Product:	[Plasma] kwin	Reporter:	iodreamify
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	akselmo, nate, xaver.hugl
Priority:	NOR	Keywords:	efficiency-and-performance
Version First Reported In:	6.4.5
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	video Weird slowdown with paused video

Description iodreamify 2025-10-06 18:57:30 UTC

SUMMARY
I have a hybrid graphics laptop with amd integrated and nvidia discrete graphics chips. Recently i've noticed when i'm on Wayland if i launch mpv on the amd integrated graphics the action to resize window on kde wayland is super slow. This does not happen if i launch mpv with xwayland. This also does not happen if i launch mpv with Wayland but on the nvidia chip. 

I also tried this on Gnome and with Gnome Wayland on the amd graphics chip this bug is no longer present. I'm not sure if this is a kwin bug but i wanted to report this since this only seems to happen on Plasma Wayland.

mpv is running on the gpu with the waylandvk context. there is also nothing in the logs and cpu usage is not going up.  

STEPS TO REPRODUCE
1. launch mpv on an amd graphics chip like the amd Rembrandt
2. try to resize the window 

OBSERVED RESULT
resize is super slow(even though it's smooth)

EXPECTED RESULT
resize is fast and keeps up with mouse

Operating System: Arch Linux 
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.2
Kernel Version: 6.16.10-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 7535HS with Radeon Graphics
Memory: 16 GiB of RAM (14,9 GiB usable)
Graphics Processor 1: AMD Radeon 660M
Graphics Processor 2: NVIDIA GeForce RTX 4050 Laptop GPU
Manufacturer: ASUSTeK COMPUTER INC.
Product Name: ASUS TUF Gaming A15 FA507NU_FA507NU
System Version: 1.0

Comment 1 iodreamify 2025-10-06 18:59:54 UTC

Created attachment 185560 [details]
video

Comment 2 Akseli Lahtinen 2025-10-07 11:26:17 UTC

Created attachment 185573 [details]
Weird slowdown with paused video

I can confirm it's doing something weird, but only when I pause the video.

Operating System: Fedora Linux 42
KDE Plasma Version: 6.5.80
KDE Frameworks Version: 6.19.0
Qt Version: 6.9.2
Kernel Version: 6.16.10-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: AMD Radeon RX 6600

Comment 3 Zamundaaa 2025-10-13 13:08:39 UTC

This is a bug in mpv, see https://github.com/mpv-player/mpv/issues/16744