Bug 432341 - Screen flickers when the screen is locked/unlocked on Wayland
Summary: Screen flickers when the screen is locked/unlocked on Wayland
Status: RESOLVED FIXED
Alias: None
Product: kscreenlocker
Classification: Plasma
Component: general (show other bugs)
Version: unspecified
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords: wayland-only
Depends on:
Blocks:
 
Reported: 2021-01-31 11:03 UTC by Patrick Silva
Modified: 2022-11-20 16:12 UTC (History)
3 users (show)

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Description Patrick Silva 2021-01-31 11:03:54 UTC
SUMMARY
On X11, we see a fade effect when the screen is locked/unlocked.
However, on Wayland the transition to/from the screen locker is not smooth,
the screen flickers instead.

STEPS TO REPRODUCE
1. start Wayland session
2. lock and unlock your screen
3. 

OBSERVED RESULT
screen flickers when the screen is locked and unlocked

EXPECTED RESULT
smooth transition to/from screen locker, like on X11

SOFTWARE/OS VERSIONS
Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.21.80
KDE Frameworks Version: 5.79.0
Qt Version: 5.15.2
Comment 1 Patrick Silva 2021-05-13 21:57:17 UTC
Less noticeable, but it also occurs on Arch Linux.

Operating System: Arch Linux
KDE Plasma Version: 5.21.90
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2
Graphics Platform: Wayland
Comment 2 Patrick Silva 2021-09-16 16:38:33 UTC
screen locking/unlocking is still not smooth on Plasma 5.23 beta.

Operating System: Arch Linux
KDE Plasma Version: 5.22.90
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Graphics Platform: Wayland
Comment 3 kde.org 2022-05-05 12:30:42 UTC
Thank you for reporting this issue. A problem causing flickering on Wayland has recently been fixed. See https://bugs.kde.org/show_bug.cgi?id=447705 for details. I'm not sure if this might also fix your problem. Can you please test and report back if the issue you are reporting still exists in 5.24.5? Should it still exist, please create a small video of the issue and attach it to this bug report or upload it somewhere (e.g. youtube) and provide a link.
Comment 4 Patrick Silva 2022-05-05 19:42:15 UTC
Tested on Arch Linux (Plasma 5.24.5) and neon unstable, on their X11 and Wayland sessions.

On Wayland session of Arch Linux Plasma panel remains visible for a few milliseconds when the screen is locked and there is no fade effect when the screen is unlocked. On X11, the screen is properly locked but there is no fade effect when the screen is unlocked.

On neon unstable I see the same result on X11 and Wayland: the screen is properly locked but there is no fade effect when the screen is unlocked.
Comment 5 Nate Graham 2022-05-09 15:29:13 UTC
Lack of fade effect is a separate thing. I think that's a recent regression. Let's get a new bug report for that.

Cannot reproduce any flickering or excessive panel visibility on Wayland.
Comment 6 Patrick Silva 2022-05-09 18:28:16 UTC
(In reply to Nate Graham from comment #5)
> Lack of fade effect is a separate thing. I think that's a recent regression.
> Let's get a new bug report for that.
reported as bug 453588
Comment 7 Nate Graham 2022-11-04 21:29:35 UTC
Can't reproduce any flickering still, though a fade effect is still missing.

Can you reproduce this issue with Plasma 5.26 on either Arch or the updated Ubuntu 22.04-based KDE Neon?
Comment 8 Bug Janitor Service 2022-11-19 05:14:28 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:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

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 9 Patrick Silva 2022-11-20 16:12:53 UTC
Cannot reproduce on Arch Linux (Plasma 5.26.3) or neon unstable.