Bug 466741 - wayland: 2 monitor setup with 175%/100% scaling: mouse scroll-wheel creates a jumping motion when operated slowly
Summary: wayland: 2 monitor setup with 175%/100% scaling: mouse scroll-wheel creates a...
Status: REPORTED
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (show other bugs)
Version: 5.27.2
Platform: Fedora RPMs Linux
: VLO minor
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-03-02 21:16 UTC by slartibart70
Modified: 2023-03-23 12:12 UTC (History)
3 users (show)

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Description slartibart70 2023-03-02 21:16:51 UTC
+++ This bug was initially created as a clone of Bug #466683 +++

Operating System: Fedora Linux 37
KDE Plasma Version: 5.27.2
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.14-200.fc37.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-7820HQ CPU @ 2.90GHz
Memory: 31,1 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 630

Setup:
Laptop with 2K Laptop screen and a fullhd screen (1920x1080) connected by displayPort
Use fullHD monitor as 'primary' and perform all tests on the fullHD monitor (ignore laptop screen)

Go to systemsettings > display config
and set 175% scale for 2K laptop screen, 100% for fullhd screen.
This makes apps/windows on both monitors the same visual size.

Problem:

- the mouse scroll-wheel behaviour on browsers  'jumps' when being operated slowly. The impression is that with each slow wheel movement, the browser scrolls up/down 3 or 4 lines at once (giving this jumpy look)
Contrast this behaviour to normal 100% scale, where slow scrolling is smooth

This is not restriced to browsers, other scrollable lists are affected as well, but this effect typically catches your attention in a long, scrollable website
Comment 1 Nate Graham 2023-03-06 17:52:46 UTC
Can kind of reproduce on Firefox (in native Wayland mode). It's very subtle and difficult to notice though.
Comment 2 slartibart70 2023-03-06 22:40:09 UTC
I did some further testing and i think this could also be related to the mouse-settings
I'm using a logitech M525 mouse and solaar running in the backround. It's using the 'scroll wheel high resolution' option set to enabled.

Depending on how you (gently) touch the scrollwheel, this causes jumps when operated slowly and gets smoother the quicker you scroll.
Maybe this has nothing to do with plasma/screen renderings

And yes, firefox behaves differently as chrome regarding scrolling.

I'd say the culprit is the mouse, i am tempted to close this as well...
Comment 3 slartibart70 2023-03-06 22:41:23 UTC
If you use it on a 4K monitor, this effect can be neglected.
On a fullHD screen it's way more noticeable
Comment 4 Nate Graham 2023-03-07 15:42:46 UTC
What is solaar?

Can you reproduce the issue with a laptop touchpad or an old fashioned clicky mouse wheel?
Comment 5 slartibart70 2023-03-07 15:44:47 UTC
https://pwr-solaar.github.io/Solaar/

A logitech device manager (better: a manager for the unifying receiver and its clients)
Comment 6 Nate Graham 2023-03-08 15:51:02 UTC
Any chance you could uninstall it temporarily (your settings won't get erased, so this is safe) and then reboot to see if the issue you're seeing goes away?
Comment 7 Bug Janitor Service 2023-03-23 03:45:40 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
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If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 8 slartibart70 2023-03-23 12:12:37 UTC
update to scrolling:
i uninstalled the mouse-addon (solaar) and also tried tweaking the sensitivity of the scroll wheel settings in systemsettings.
The jumpiness remains, but it's much more fine-grained controllable.