With the Plasma 5.0 release out the door, we can lift our heads a bit and look forward, instead of just looking at what’s directly ahead of us, and make that work by fixing bug after bug. One of the important topics which we have (kind of) excluded from Plasma’s recent 5.0 release is support for Wayland. The reason is that much of the work that has gone into renovating our graphics stack was also needed in preparation for Wayland support in Plasma. In order to support Wayland systems properly, we needed to lift the software stack to Qt5, make X11 dependencies in our underlying libraries, Frameworks 5 optional. This part is pretty much done. We now need to ready support for non-X11 systems in our workspace components, the window manager and compositor, and the workspace shell.
Let’s dig a bit deeper and look at at aspects underlying to and resulting from this transition.
Why Wayland?
The short answer to this question, from a Plasma perspective, is:
- Xorg lacks modern interfaces and protocols, instead it carries a lot of ballast from the past. This makes it complex and hard to work with.
- Wayland offers much better graphics support than Xorg, especially in terms of rendering correctness. X11′s asynchronous rendering makes it impossible to be sure about correctness and timeliness of graphics that ends up on screen. Instead, Wayland provides the guarantee that every frame is perfect
- Security considerations. It is almost impossible to shield applications properly from each other. X11 allows applications to wiretap each other’s input and output. This makes it a security nightmare.
I could go deeply into the history of Xorg, and add lots of technicalities to that story, but instead of giving you a huge swath of text, hop over to Youtube and watch Daniel Stone’s presentation “The Real Story Behind Wayland and X” from last year’s LinuxConf.au, which gives you all the information you need, in a much more entertaining way than I could present it. H-Online also has an interesting background story “Wayland — Beyond X”.
While Xorg is a huge beast that does everything, like input, printing, graphics (in many different flavours), Wayland is limited by design to the use-cases we currently need X for, without the ballast.
With all that in mind, we need to respect our elders and acknowledge Xorg for its important role in the history of graphical Linux, but we also need to look beyond it.
What is Wayland support?
KDE Frameworks 5 apps under Weston
Without communicating our goal, we might think of entirely different things when talking about Wayland support. Will Wayland retire X? I don’t think it will in the near future, the point where we can stop caring for X11-based setups is likely still a number of years away, and I would not be surprised if X11 was still a pretty common thing to find in enterprise setups ten years down the road from now …
