Xaver’s blog

This one required a few other features to be implemented first, so let’s jump right in.

In Plasma 6.2, KWin switched from doing linear blending with HDR to blending in a gamma 2.2 space. Let’s take a look at what that means, and why it was done.

Fractional scaling is hard. Anyone that had the misfortune of working on it knows that… so it won’t surprise a lot of people that it’s not all figured out yet! Today I’ll talk about the fractional scaling problems with KWin’s server side decorations, and why we need to do an API break to fix it.

Profiling displays is already not a super simple thing on its own, but things get more complicated when you try to profile your display in Wayland - profiling applications don’t support Wayland yet, some APIs on the compositor side to make it work well are still missing, and there’s a general lack of information on the topic. So today I’ll show...

KWin had a very long standing bug report about bad performance of the Wayland session on older Intel integrated graphics. There have been many investigations into what’s causing this, with a lot of more specific performance issues being found and fixed, but none of them managed to fully fix the issue… until now.

Since the last two posts about this topic (part one, part two) there has been some more progress, so let’s take a look.

Recently news went around about explicit sync being merged into Wayland protocols, and in the wake of that I saw a lot of people having questions about it, and why it was such a big deal… So here’s a short-ish explanation of what it is, why it’s needed and what the benefits are over the old model.

In my last post about HDR and color management I explained roughly how color management works, what we’re doing to make it work on Wayland and how far along we were with that in Plasma. That’s more than half a year ago now, so let’s take a look at what changed since then!

The solution and the problem: atomic modesetting When it comes to driving displays on Linux there’s some legacy APIs that we don’t care about, and the drm/kms API. This API isn’t exactly one API though, it has two variants, legacy modesetting and atomic modesetting.

In this post I’ll talk a bit about HDR and color management, and where we are with implementing them in KWin. Before jumping into the topic though, I need to add a disclaimer: I will be simplifying a lot of things significantly, leaving others out entirely and as I am by far not a color expert, almost certainly write a few things that are wrong....

Until recently, the drm backend of KWin used gbm_surfaces for getting buffers to display on the screen. This is a relatively simple API that allows to extend what one can do with a EGL surfaces - you get to directly choose buffer format and modifiers and you get a gbm buffer after rendering a frame, which you can then use with the drm API to...

A considerable amount of people assume Wayland isn’t particularly suitable for gaming, usually because you can’t turn off the compositor. This post will challenge that assumption and see how the current state of gaming on Wayland is, with a focus on KWin, KDEs compositor.