https://bugs.kde.org/show_bug.cgi?id=456300

            Bug ID: 456300
           Summary: Screen sharing broken when using non-standard screen
                    resolutions
           Product: kwin
           Version: 5.25.2
          Platform: Archlinux Packages
                OS: Linux
            Status: REPORTED
          Severity: normal
          Priority: NOR
         Component: wayland-generic
          Assignee: kwin-bugs-n...@kde.org
          Reporter: vps...@gmail.com
  Target Milestone: ---

Created attachment 150375
  --> https://bugs.kde.org/attachment.cgi?id=150375&action=edit
native resolution

SUMMARY
When using a screen with an arguably _non-standard_ (or should I say
_not-so-common_) resolution, screen sharing is pretty much broken on
Chromium-based browsers. The "recording stream" looks glitchy and borked, for
some reason. This didn't happen in Plasma 5.24.x, though. Please see pictures
attached.

Strangely enough, things work great on Firefox and OBS, but this wasn't broken
in Plasma 5.24. Things also work if I scale back to a rather more common
resolution, i.e. 2560x1080, 1920x1080, etc. In fact, I'm only able to reproduce
the bug using my monitor's native resolution (3440x1440).

STEPS TO REPRODUCE
1. Use any website that allows you to record your screen (zoom, jitsi,
screenapp.io, etc).


OBSERVED RESULT
The captured stream looks glitchy, with lots of artifacts. Almost as if the
computer were having GPU issues.

EXPECTED RESULT
No glitches or screen artifacts in the recorded stream.

SOFTWARE/OS VERSIONS
Linux Version:
5.15.2 
Note: This doesn't seem to be a kernel issue, since I am able to reproduce the
same behavior in kernel versions 5.15.x - 5.18.x.
---
KDE Plasma Version: 
5.25.2-1
---
KDE Frameworks Version: 
5.95.0-2
---
Qt Version: 
5.15.5+kde+r166-1

ADDITIONAL INFORMATION
- I'm using my laptop's integrated graphics (Intel 8th gen U-series CPU). It
has no issue driving the 2k screen
- I'm pretty sure this is not a driver/mesa issue since I was unable to
reproduce the same issue on GNOME 42 + same chromium release
- I tried using older chromium releases (pre 103.x) to no avail 
- I did enable pipewire support in chrome://flags
- I'm able to reproduce the same behavior using Flathub's Chromium, Brave,
Arch's Chromium and ungoogled-chromium as well
- I tried forcing Chromium's VAAPI support to see if it was a hardware-accel
related issue, but that doesn't seem to be the case.
- It looks like Chromium fails to call GetVSyncParametersIfAvailable() but ONLY
when I use my display's native resolution. No such thing happens when I use
smaller display resolutions. Maybe kwin is failing to provide some necessary
info?

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