Bug 503398

Summary: On certain hardware/software combinations, volume slider in the Audio Volume widget does not follow the pointer smoothly when being dragged
Product: [Plasma] plasmashell Reporter: Filip <filip.kendes1>
Component: Audio Volume widgetAssignee: Plasma Bugs List <plasma-bugs-null>
Status: CONFIRMED ---    
Severity: minor CC: isma.af, janbidler00, john.kizer, mikefrag96, nate, sephiroth_pk
Priority: NOR Keywords: regression
Version First Reported In: 6.3.4   
Target Milestone: 1.0   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: showcase

Description Filip 2025-04-26 18:01:09 UTC
Created attachment 180690 [details]
showcase

SUMMARY
Volume bar in the Audio Volume widget freezes until OSD audio volume completes its animation.

Also, I think it's redundant to have OSD in this case because the volume percentage is already displayed in the audio volume widget and user is focused on it so maybe not display it at all?

STEPS TO REPRODUCE
1. Change the audio volume in fast motion using the audio volume widget

OBSERVED RESULT
Widget volume is frozen when user moves the volume fast

EXPECTED RESULT
Widget volume is not frozen

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.13.0
Qt Version: 6.9.0
Kernel Version: 6.14.3-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-6600K CPU @ 3.50GHz
Memory: 7.7 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 970
Comment 1 John Kizer 2025-04-27 21:04:51 UTC
I can reproduce on Fedora KDE 42 - just to note, the cause could possibly still be linked to the OSD, but the issue seems to occur even if the OSD is disabled.

Thanks!
Comment 2 Nate Graham 2025-04-28 16:15:16 UTC
*** Bug 503476 has been marked as a duplicate of this bug. ***
Comment 3 John Kizer 2025-04-28 17:41:59 UTC
Trying this out on all my available devices, since I noticed the three folks who directly observed it all have NVIDIA cards - which sent the alarm bells ringing...

* NVIDIA graphics: slider just stops moving until it suddenly appears in the new position
* Unaccelerated graphics (VM): slider moves at a low framerate, and lags behind the cursor
* AMD graphics: seems *almost* perfectly smooth

So perhaps there's some graphics driver issue?
Comment 4 Filip 2025-04-28 18:14:01 UTC
It's reproducible using nouveau and proprietary drivers.
Comment 5 Filip 2025-04-28 18:16:36 UTC
Sorry for double message, I need to add that I can't test on AMD GPU because I don't have one unfortunately.
Comment 6 Jan Bidler 2025-05-26 10:06:51 UTC
*** Bug 504802 has been marked as a duplicate of this bug. ***
Comment 7 Riccardo Robecchi 2025-08-27 16:39:17 UTC
I can confirm that it is smooth on AMD (and X11), however on my secondary laptop with an Intel processor (i5-8250U) and Wayland it lags terribly.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Endeavour OS
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.1
Comment 8 Riccardo Robecchi 2025-08-27 17:30:44 UTC
Sorry for the unintended spam - I switched to X11 to debug another issue and this one appears to be different. Sometimes it lags, sometimes it doesn't; when it doesn't, however, it starts adjusting the volume after a couple of seconds, enough so that I have already closed the widget and it therefore makes random adjustments. Supremely weird!