Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

paperlunch · 2026-02-01 08:01:43

Hi,

I have a fresh installation of Arch Linux running Wayland, Sway on an Asus Rog laptop (~2021) with an AMD CPU, iGPU and an Nvidia dGPU (Nvidia driver). Three outputs are used, the built-in screen and two external monitors.

I've been experiencing short freezes lasting around or less then a second. Sometimes often, several times a minute, sometimes not occurring for tens of minutes. The UI and mouse become unresponsive, sound glitches and skips. If a key is being pressed when the freeze starts it's repeated 30 times by the time the freeze ends. It is unpredictable when the freeze happens, sometimes when moving windows around, sometimes when simply using vim in the terminal.

How should I go about diagnosing the problem, what log files, debug output should I be looking at? What information should I post here so that the issue can be better triangulated?

Thank you.

- AMD Ryzen 7 4800H with Radeon Graphics
- GeForce RTX 3050 Ti Mobile

Last edited by paperlunch (2026-02-01 08:32:06)

seth · 2026-02-01 10:29:57

For general oversight and kernel problems
Please post your complete system journal for the boot after such freezes

sudo journalctl -b | curl -F 'file=@-' 0x0.st

Then monitor top to see whether and which process(es) hog the CPU and to see whether sway is victim or culprit, try a different display server (i3, weston, hyprland, …)

paperlunch · 2026-02-01 11:46:04

Kernel logs: http://0x0.st/Pq52.txt. i3 worked fine without freezes. Hyperland had short lags but not complete freezes.

seth · 2026-02-01 14:46:47

So sway specific - are you running sway on the AMD or the nvidia GPU (and please post your Xorg log, https://wiki.archlinux.org/title/Xorg#General for that configuration and comparism)
Also maybe your sway config, check whether it consumes a lot of CPU and in doubt run it in debug mode, https://github.com/swaywm/sway/wiki#troubleshooting

Sidebar, disable iwd.service and in doubt see https://wiki.archlinux.org/title/Networ … Fi_backend

paperlunch · 2026-02-08 09:52:09

Here is a sway debug log, on line 00:02:20.672 there is a direct log warning of slow input processing.
Output of nvidia-smi, it seems that sway is using the nvidia card a little. It must be using it since DP-1 output connection is wired directly to the nvidia card. Memory usage is 1Mb, maybe it's just copying an output buffer to it but otherwise using the AMD iGPU for rendering.
The i3 and Xorg configuration was unfortunately on another installation on the same machine and I don't have it.
When I move firefox from one screen to another quickly and repeatedly, it does sometimes trigger the freeze. Looking at top -p <swaypid> -d0.5 it seems that the freeze happens when sway reaches close 100% cpu utilization, but it never goes above 100%. Which leads me to believe that it's only utilizing a single CPU core out of the 8.

seth · 2026-02-08 14:33:23

The i3 and Xorg configuration was unfortunately on another installation on the same machine and I don't have it.

What immediately puts into question

seth wrote:

So sway specific

Test it on the current configuration - will also get you the log.

00:00:00.459 [DEBUG] [sway/desktop/output.c:534] New output 0x55d2be82e9d0: eDP-1 (non-desktop: 0)
00:00:00.459 [INFO] [wlr] [backend/drm/drm.c:1855] connector HDMI-A-1: Requesting modeset
00:00:00.459 [DEBUG] [sway/desktop/output.c:534] New output 0x55d2be82ec80: HDMI-A-1 (non-desktop: 0)
00:00:00.459 [INFO] [wlr] [backend/drm/drm.c:1741] Scanning DRM connectors on /dev/dri/card0
00:00:00.502 [INFO] [wlr] [backend/drm/drm.c:1796] Found connector 'DP-1'
00:00:00.502 [INFO] [wlr] [backend/drm/drm.c:1821] 'DP-1' connected

Do you get this w/o DP-1, only eDP-1 and HDMI-A-1 ?

00:00:00.548 [ERROR] [wlr] [backend/drm/drm.c:1129] Failed to pick cursor plane format
00:00:00.548 [DEBUG] [wlr] [types/output/cursor.c:424] Falling back to software cursor on output 'DP-1'

Do you run into this when disabling HW cursors entirely?
https://wiki.archlinux.org/title/Sway#No_visible_cursor

Which leads me to believe that it's only utilizing a single CPU core out of the 8.

The bigger question is why it completely charges one core tbw.

paperlunch · 2026-02-09 10:22:49

I have opted to replace the nvidia driver with nouveau. This seems to have lowered cpu usage substantially and no freezes so far.

I have tried disabling hardware cursor with WLR_NO_HARDWARE_CURSORS=1, CPU usage remained high with occasional freezes, sway log for it. (line 1514 shows the option set to 1).

Arch Linux

#1 2026-02-01 08:01:43

Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

#2 2026-02-01 10:29:57

Re: Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

#3 2026-02-01 11:46:04

Re: Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

#4 2026-02-01 14:46:47

Re: Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

#5 2026-02-08 09:52:09

Re: Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

#6 2026-02-08 14:33:23

Re: Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

#7 2026-02-09 10:22:49

Re: Recurring short freeze / stutter / lag / soft lockup on Wayland - Sway

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