Bug 444303

Summary:	Conflicting information about monitor refresh rate
Product:	[Plasma] kwin	Reporter:	benttotheright
Component:	platform-drm	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	sattaxt
Priority:	NOR
Version First Reported In:	5.23.1
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:	https://invent.kde.org/plasma/kwin/commit/1fb8ebc92cbecaf5ddca538e412eb7484e89eb51	Version Fixed/Implemented In:	5.23.2
Sentry Crash Report:
Attachments:	xrandr and drm_info output

Description benttotheright 2021-10-24 02:15:12 UTC

Created attachment 142806 [details]
xrandr and drm_info output

SUMMARY

Two monitor setup:
1) 1440p@144Hz with FreeSync 
2) 1080p@60Hz

According to VRRTest, the primary monitor does indeed run at 144Hz and FreeSync is enabled as well. 

When I check wayland-info or xrandr, that monitor is shown to be running at 59.951 and 59.91Hz, respectively. Similarly, mpv does show that the display fps are 59.951. 

On the other hand, drm_info shows a mode titled "2560x1440@144.01 driver phsync nvsync" and a mode titled "2560x1440@59.95 preferred driver phsync nvsync".

Something doesn't really add up here. 


STEPS TO REPRODUCE
1. run "xrandr"
2. run "wayland-info"
3. run "drm_info"
4. run "kscreen-doctor -o"
5. check display configuration
6. compare reported values for display refresh rate

OBSERVED RESULT

The refresh rate varies across different information sources.

EXPECTED RESULT

The information across those different sources should align.


SOFTWARE/OS VERSIONS

Linux/KDE Plasma: EndeavourOS, 5.14.14-arch1-1
(available in About System)
KDE Plasma Version: 5.23.1
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.2

Comment 1 Bug Janitor Service 2021-10-24 12:02:22 UTC

A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/1561

Comment 2 Zamundaaa 2021-10-24 16:37:59 UTC

Git commit ca58ee875f269fd6a8fc222f5690fa2522304e7e by Xaver Hugl.
Committed on 24/10/2021 at 12:01.
Pushed by zamundaaa into branch 'master'.

WaylandOutput: schedule update on mode change

Without this there can be a mismatch between what clients expect and what
KWin actually uses, causing for example stutter in video players.
FIXED-IN: 5.23.2

M  +1    -0    src/waylandoutput.cpp

https://invent.kde.org/plasma/kwin/commit/ca58ee875f269fd6a8fc222f5690fa2522304e7e

Comment 3 Zamundaaa 2021-10-24 16:38:20 UTC

Git commit 1fb8ebc92cbecaf5ddca538e412eb7484e89eb51 by Xaver Hugl.
Committed on 24/10/2021 at 16:38.
Pushed by zamundaaa into branch 'Plasma/5.23'.

WaylandOutput: schedule update on mode change

Without this there can be a mismatch between what clients expect and what
KWin actually uses, causing for example stutter in video players.
FIXED-IN: 5.23.2


(cherry picked from commit ca58ee875f269fd6a8fc222f5690fa2522304e7e)

M  +1    -0    src/waylandoutput.cpp

https://invent.kde.org/plasma/kwin/commit/1fb8ebc92cbecaf5ddca538e412eb7484e89eb51

Comment 4 Vlad Zahorodnii 2021-10-26 10:39:48 UTC

*** Bug 444420 has been marked as a duplicate of this bug. ***