Bug 510239

Created attachment 185513 [details]
idle iGPU usage corresponding to minute clock updates

SUMMARY

While the start bar or `Panel` visibility is hidden, idle iGPU usage spikes from 0% to a sustained ~10% whenever the widget for the `Digital Clock` updates the current time. For example, until the Panel is made visible via some user interaction via mouse or keyboard, the `plasmashell` process spikes idle iGPU usage spikes to a sustained ~10% upon any advancement of the current minute of the day, or second of the day if the Digital Clock is configured to always show seconds.

STEPS TO REPRODUCE
1. Add Digital Clock to Panel
2. Set Panel visibility to `Always visible`
3. Use `nvtop` to view idle iGPU usage baseline
4. Set Panel visibility to `Auto hide`
5. Wait for wall time to advance to next minute

OBSERVED RESULT

iGPU usage spikes in sync with clock updates.

EXPECTED RESULT

Visibility of Digital Clock should not greatly affect idle iGPU usage.

SOFTWARE/OS VERSIONS
Operating System: NixOS 25.11
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.2
Kernel Version: 6.16.9 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-6700HQ CPU @ 2.60GHz
Memory: 32 GiB of RAM (31.2 GiB usable)
Graphics Processor 1: Intel® HD Graphics 530
Graphics Processor 2: NVIDIA GeForce GTX 960M
Manufacturer: Dell Inc.
Product Name: XPS 15 9550

ADDITIONAL INFORMATION
Issue persists with or without Nvidia drivers installed.
I.e. even when only the Intel iGPU is loaded by kernel.

I suspect this may be a bigger issue than just the digital clock, and more to do with the general update events and display rendering. As when screen recording this issue (from my dGPU), my idle iGPU usage would only flatline when I hovered over the panel to focus it's visibility in view, but would hold at ~10% when hidden.