Window brightness changing/flickering when screen updates on Vivaldi

Help
,
1

Not sure what this bug is related to so sorry if this isn’t a KDE problem.

When something on screen changes like scrolling on a page or hovering over buttons the brightness of the browser window changes. This only happens when the brightness is set to something lower than 100%. When at 100% brightness the brightness of the window doesn’t change. No other program window or browser like Firefox has this problem. Only the browser window is effected. The display brightness is always the same.

I never had this problem on any previous Plasma versions but other things also updated like drivers and browser version so I can’t say if this a problem with Plasma 6.8.

I would have liked to upload a video but I cant. The problem is only visible on the display and not a screen recording.

OS: CachyOS
Kernel version: 7.2.9-2
Using KDE Plasma 6.8.0
GPU 1: Intel UHD Graphics (Intel 11800H CPU)
GPU 2: RTX 3060 Mobile with driver 615.78.08

2

Welcome to the forum! (I don’t know if you are new, but I’ll welcome you anyway).

Screen recordings should suffice. If it doesn’t record it, the issue an odd one for sure. I assume you’ve tried OBS Studio, picking the whole monitor as your output?

Also you can convert your video to .webp using ImageFlow from Flathub: Install ImageFlow on Linux | Flathub . I used this before, and sometimes I have to tweak quality or framerate so that it’s small file size. But then you attach it here.

Or create a bug report on bugs.kde.org, which supports any video attachments. You can create the bug with the “I don’t know” classification. Importantly, note what circumstances you are in, and add that to “STEPS TO REPRODUCE”. I can give some guidance; it could probably look like this:

  • Use CachyOS
  • Install Vivaldi (be specific about whether it’s a CachyOS package or another format)
  • Turn down screen brightness.
  • Use monitor with these specs:
  • Use PC with “this” CPU and “this” GPU
  • Scroll through Vivaldi
3

Since it only happens when the display brightness is below 100% and only in one browser, I’d suspect the browser’s GPU compositing path rather than Plasma itself. A quick test: in Vivaldi’s settings, search for “hardware acceleration”, turn it off, restart Vivaldi, and see if the brightness shift disappears. If it doesn’t, try launching Vivaldi once with the flag --ozone-platform=x11 (or --ozone-platform=wayland if you’re currently on XWayland) to check whether it’s tied to how it talks to KWin. It would also help to see whether Chromium or Chrome reproduces it, since Vivaldi is built on the same engine. If one of those toggles fixes it, mention that in a bug report to KDE along with your GPU, driver version and whether you’re on Wayland, because that will narrow down where the dimming is being applied.

4

That sounds like some good tests!
Also, we don’t know their terminal experience, let’s assume none for now.

To apply the flags to Vivaldi, which is what Novastart suggested, open Konsole. Then copy-paste this:

vivaldi --ozone-platform=x11

Pasting in a terminal is done with Ctrl Shift V. Then press enter.

To do the same for the Wayland variant, close Vivaldi, then go back to Konsole, and paste this:

vivaldi --ozone-platform=wayland

I hope this clarified the “flag” part of Novastart’s message!

5

Spectacle is what I tried using to record the screen but it looks fine on the recording.
Here’s a converted webp of the problem.

MVI_4548

6

I tried launching it with Wayland or X11 with those commands and it makes no difference. I’m using KDE Plasma 6.8.0 so I think X11 was removed. Wouldn’t it be using Xwayland anyway?

Turning off hardware acceleration seems to fix it. Maybe I should go and make a bug report to Vivaldi instead?

Another thing I just realised is that it only seems to happen when the window is maximized. There’s no problem if I make the window smaller.