Bug 407024

Summary:	Panel texture flickering
Product:	[Plasma] plasmashell	Reporter:	Lastique <andysem>
Component:	Panel	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	nate, notmart, plasma-bugs
Priority:	NOR
Version:	5.15.4
Target Milestone:	1.0
Platform:	Kubuntu
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=406882
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Screencast showing the problem

Description Lastique 2019-04-28 19:04:38 UTC

SUMMARY
I noticed texture flickering in a few cases.

STEPS TO REPRODUCE
Scenario 1.
1. Create a horizontal panel with a few application icons.
2. Move the mouse over the icons on the panel. Try moving fast enough so that tooltips with the icon name don't appear.

Scenario 2.
1. Invoke logout/reboot/shutdown effect.

OBSERVED RESULT
Scenario 1.
The panel texture is flickering. I can see its opacity vary, as well as contents jitter during the flickering.

Scenario 2.
The screen dimming effect of the logout/reboot/shutdown animation has flickering opacity. After the animation completion, sometimes the effect darkens the desktop contents more than usual, and then after a fraction of a second (or maybe after I move the mouse) opacity gets restored to usual (which looks like desktop contents become less darkened).

While the animation is in progress, the logout/reboot/shutdown icons flicker.

EXPECTED RESULT
No flickering should happen.

SOFTWARE/OS VERSIONS
Linux: Kubuntu 19.04
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.56.0
Qt Version: 5.12.2
Mesa: 19.0.2
X.org: 1.20.4

ADDITIONAL INFORMATION
I'm seeing this on a laptop with Intel Haswell iGPU (i915 driver).
I've also seen the problem with logout/reboot/shutdown effect on a different machine, also with Kubuntu 19.04, but with Nvidia GPU (430.09 driver). Not the panel flickering, though.

Comment 1 Lastique 2019-05-26 16:04:33 UTC

Created attachment 120326 [details]
Screencast showing the problem

I've recorded a video showing the problem.

The problem reproduces with different plasma themes: Breeze, Breeze Light, Kubuntu.

Comment 2 Lastique 2019-05-26 16:19:55 UTC

I think, I found a workaround. In xorg.conf, for the Intel iGPU, I've added this option:

    Option "DRI" "3"

In my case, I have Intel iGPU section in a separate file /etc/X11/xorg.conf.d/20-intel.conf, which now looks like this:

    Section "Device"
        Identifier  "card0"
        Driver      "intel"
        Option      "Backlight"  "intel_backlight"
        Option      "DRI" "3"
        BusID       "PCI:0:2:0"
    EndSection

Comment 3 Nate Graham 2021-03-10 04:26:24 UTC

Is this still happening to you in Plasma 5.21?

Comment 4 Lastique 2021-03-10 08:17:48 UTC

(In reply to Nate Graham from comment #3)
> Is this still happening to you in Plasma 5.21?

It's not released in Kubuntu yet, so I can't test.

Comment 5 Marco Martin 2021-03-10 11:43:30 UTC

May be a KWin issue?

Comment 6 Nate Graham 2021-11-16 18:10:52 UTC

Can you test again?

Comment 7 Lastique 2021-11-16 18:27:56 UTC

The logout scenario reproduces on my machine with a Nvidia GPU:

Operating System: Kubuntu 21.10
KDE Plasma Version: 5.22.5
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Kernel Version: 5.13.0-21-lowlatency (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-2600K CPU @ 3.40GHz
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2
Nvidia driver: 470.86

As the darken effect is animated, the power off icon in the center sometimes flicker. This is much less obvious than it was initially when I reported the problem, and sometimes is not visible at all, but still happens.

Comment 8 Lastique 2021-11-17 11:20:15 UTC

On my Intel GPU system this no longer reproduces, neither the panel flickering nor the logout screen.

Operating System: Kubuntu 21.10
KDE Plasma Version: 5.22.5
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Kernel Version: 5.13.0-21-lowlatency (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-4700HQ CPU @ 2.40GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4600

Comment 9 Nate Graham 2023-09-18 20:55:58 UTC

Ok great, thanks!