PowerDevil in Plasma 6.0 and beyond

Hi, I'm Jakob and this is my new KDE blog. Let's see how this goes as I haven't blogged for literally decades.

This is a companion discussion topic for the original entry at https://blogs.kde.org/2024/04/23/powerdevil-in-plasma-6.0-and-beyond/

Great read, thanks for the write-up!
I don’t think the performance icon is on spot. The lightnings made me think of electricity which I associate more with energy savings than performance. I propose a sprinter, or something with comic-like speed lines. A speed-meter with the indicator at max / right is a common icon, too.


I like that idea! CC @Anditosan with his icon design expertise. Personally I associate the speedometer icon also more with “speed” rather than balanced, even though on closer look the needle isn’t on the far right. Making an icon that intuitively conveys balanced a.k.a. “not too much of either” is no easy feat :stuck_out_tongue:

An actual balance? People might mistake that for law or justice. Yin and Yang or Taijitu might stand for balance, too. But it is associated with a religion.

In fact, when I search online, it seems that the symbol for performance most used is the one we use for balanced performance.


Great blog post. Super comprehensive.

Your initial description of what powerdevil does makes me feel like there’s a substantial amount of conceptual overlap with KWin, at least on Wayland. Notably, KWin on Wayland ate monitor arrangement configuration in Plasma 6; KScreen is no longer involved except on X11 where it’s been feature-frozen.

Food for thought.

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Indeed. Note the sentence toward the bottom where it says that we want to move brightness handling into KWin. Here’s how I figure this will happen:

  1. We finish the work on per-monitor brightness support, with all the necessary refactoring and D-Bus API for the brightness applet to access.
  2. We take ScreenBrightnessController out of PowerDevil and put it into libkscreen as a library, similar to how DPMS has already been moved out.
  3. PowerDevil keeps using it on X11, but on Wayland, KWin uses the library and adds some fancy extra functionality that pure backlight adjustments can’t provide. PowerDevil forwards D-Bus calls to KWin via a new Wayland protocol.

There’s been some good discussion in this KWin issue, which I didn’t link from the blog post but is definitely on my mind as I go about further changes.

DPMS is already implemented by KWin in Wayland, with PowerDevil only figuring out when the screens should get turned off.