To me, this is the first time Wayland feels like it's not a waste of time. The display server does not need to have the complexity of window managing on top the surface management. I certainly share the author's sentiment:
> Although, I do not know for sure why the original Wayland authors chose to combine the window manager and Wayland compositor, I assume it was simply the path of least resistance.
Although I'm not sure if it was the least resistance per se (as a social phenomenon), but just that it's an easier problem to tackle. Or maybe the authors means the same thing.
(That and the remote access story needs to be fixed. It just works in X11. Last time I tried it with a system that had 90 degree display orientation, my input was 90 degrees off from the real one. Now, this is of course just a bug, but I have a strong feeling that the way architecture Wayland has been built makes these kind of bugs much easier to create than in X11.)
Wasn't one of Wayland's key design features combining the window manager and compositor? I am not too familiar with its history but surely there have been presentations or papers about the Wayland designers' reasoning for doing so.
Well, that's exactly what the article is about. Wayland put all together into one process I order to avoid unnecessary context switch. This protocol aims to keep the performance advantages of Wayland without giving up on separation of graphics c server and window manager.
I was responding to this comment in the article and wondering about the historical context:
> Although, I do not know for sure why the original Wayland authors chose to combine the window manager and Wayland compositor, I assume it was simply the path of least resistance.
When the window manager is a separate process with async communication between the WM and display server things can get out of sync for a frame or two which leads to visual artifacts. In Wayland the window manager works synchronously with the compositor so that it's never out of sync.
Yeah, that makes sense. It seems like instead of introducing another IPC protocol like this project does, there could be a compositor that loads different window managers as plugins. Then everything is in the same process and there is no need for async communication. Of course a crash in the window manager would take down the compositor, but this is already true for Wayland compositors that combine both.
I'm currently using a fully vibe-coded, personal River window manager that works just how I want it to. I switched to it after I realized I couldn't do everything I wanted in Hyprland (e.g. tile windows to equal areas instead of BSP by default).
Simple example of how impactful this separation has been for me.
The fact that Wayland can't just substitute out pluggable WMs without changing a bunch of other unrelated infrastructure is IMO one of the biggest user-facing losses relative to X11. Anybody who is working to improve that is doing god's work as they say.
Not only a loss but a key disabler. Having used to having the same customized window manager for decades it's impossible to change to Wayland until there's a fully equivalent interface for managing windows so that everything works as I want from mouse clicks to keyboard shortcuts. Maybe it could be an existing window manager adding support for River, or Wayback layer that reimplements an X11 desktop root on top of a minimal Wayland compositor, but none of the current Wayland compositors even scratch the surface of this.
Handwaving "just expose an API" ignores the mess at the extension boundary. Modular only works if the contract is airtight, and with Wayland's churn and "sorta spec" documenation, that sounds optimistic at best.
Every "flexible" API turns into a leaky mess unless someone is paid to write the dullest test suite in existance, and nobody is. Mandating one design is ugly, but pretending composition is free is a fairy tale.
We need a compositor that exposes everything as an extension. Preferably in a hot-reloadable, tweakable way, say, using Lua (with JIT). And also exposing its APIs in a way that allows having an analog of xdotool.
It's a damper on development of new WMs and DEs, too. I have ideas for my own desktop I'd like to explore at some point, and if I do it'll almost certainly be X11 based initially because it's so much more quick and easy to wrap one's head around and get the iteration loop up and running with.
I'm not anti-Wayland and I think X11 has enough issues that it's worth transitioning over to something better but this is a critical weakness in Wayland's design.
That's not the same thing. It's way easier to write an X11 window manager than to write a Wayland compositor, even with something like wlroots, because the window manager can speak the same protocol that clients speak, and it runs as a separate process.
As a concrete example, Emacs' EXWM package works by implementing an X11 client library in Emacs Lisp, then using it to talk to the X server (which is a separate process, so this works fine) and telling it how to position windows.
Whereas on Wayland, this is not possible without re-implementing a standalone compositor process, because otherwise architecturally it doesn't work. Emacs can't both do the drawing and be drawn.
EWM implements a Wayland compositor as a native thread spawned by a dynamic module in Emacs, it's a full compositor within the Emacs process: https://codeberg.org/ezemtsov/ewm
So it is architecturally possible (but infeasible in plain Emacs Lisp).
This one could technically be written in plain Emacs Lisp, but I'm happy to use something that already has all the XML codegen stuff for Wayland figured out. Dynamic modules work pretty well, fwiw.
No, that still requires you to make the whole thing, you just get help. For instance, I've run into a problem where I try some great new compositor that uses wlroots, and even though wlroots has good support for keyboard layouts I can't actually set the layout because the compositor hasn't wired up that functionality.
Especially with LLMs, the cost here is down significantly. People also drastically over-idealize what making an X window manager entailed: sure X had it's compositor, but you had to build so so much yourself.
I'm glad River is trying to create a bigger base here; this is way cool. And it sort of proves the value of Wayland: someone can just go do that. Someone can just make a generic compositor/display-server now, with their own new architecture and plugin system, and it'll just work with existing apps.
We were so locked in to such a narrow limited system, with it's own parallel abstraction layer to what the kernel now offers (that didn't exist when X was created). It's amazing that we have a chance for innovation and improvement now. The kernel as a stable base of the pyramid, wlroots/sway as a next layer up, and now River as a higher layer still for folks to experiment and create with. This could not be going better, and there's so much more freedom and possibility; this is such a great engine for iteration and improvement.
"Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that.""
The Wayland standard does not prescribe it (unlike X), and the reference implementations were monolithic for a very long time.
Wayland in general had a rather cavalier approach to doing away with things that X users take for granted, like, well, making screenshots. Eventually, under pressure, those in charge agreed that these features are actually very important for real users, so implementations appeared. It's an understandable way to discover the minimal usable subset of features, but the process of it is a bit frustrating for the early adopters.
I've never used a system with Wayland (been on i3 for ~15 years) but every time a project like this comes up, I have to wonder why Wayland is even a thing. So many hoops to jump through for things that should be simple.
Sure, X11 has warts but I can make it do basically anything I want. Wayland seems like it will always have too much friction to ever consider switching.
I've been on wayland since KDE had it available (like the KDE 5 days) because it offered fractional HiDPI scaling that wasn't buns. As a laptop user, it has been one of the best features of Wayland.
Furthermore, getting stuff like VRR on Wayland working is way easier than X.org. And, Wayland also supports HDR.
There's a type of input called "DeviceEvent" which is a bit lower level than "Window event". It also occurs even if the window isn't "active".
Windows and X11 support this, but Wayland doesn't except for mouse movement. I noticed my program stopped working on Linux after I updated it. Ended up switching to Window Events, but still kind of irritating.
It runs just fine at 165 hz for me. Given that xrandr and CRTs have been around for a while, and both have supported high refresh rates for a long while, something seems fishy here. Something is probably at fault, but it's not X11.
Lots of weird misinformation in the comments here. Wayland doesn't choose anything. It leaves the compositor to decide where to position a window and whether or not that window receives key presses or not. The program can't draw wherever it wants or receive system wide keystrokes or on behalf of another program. When appropriately implemented the screenshot system is built directly into the compositor. It's an API that let's a program request read access to a part of the screen and the compositor provides upon approval. It's much more secure that way and it works perfectly fine these days. Unfortunately not every compositor implements this.
A project that has a daemon run in the background as a root service and that can provide an appropriate shim to pass key strokes to anything you want.
And just to be clear the appropriate secure model is to have a program request to register a "global" hot key and then the compositor passes it to the appropriate program once registered. This is already a thing in KDE Plasma 6 and works just fine.
Insightful article. I don't recall ever viewing an easy-to-follow lesson, tutorial or book for that matter that clearly explained the various components of a Linux Desktop environment. Always had to follow complicated and obscure guides to do this and that, when solving issues, but seldom did any explain their functions clearly.
Separating the compositor and window manager feels like one of those ideas that seems obvious in hindsight, but the protocol/state-machine design here shows why it took real work to make it practical.
Lowering the barrier for writing Wayland window managers without forcing everyone to build a full compositor seems like a big win.
i'm a little thrown, because the Wayland diagram doesn't feel quite right. the compositor does lie between the kernel and the apps, but IIRC the apps have their own graphics buffers from the kernel that they are drawing into directly. the compositor then composites them together. to me, that feels more like the kernel is at the center of the diagram here: the wayland compositor is between the kernel and the output / input.
i don't think it has a huge impact on the discussion here. but this is such a key difference versus X, that i think is hugely under-told: Wayland compositors all rely on lots of kernel facilities to do the job, where-as X is basically it's own kernel, has origins where it effectively was the device driver for the gpu, talking to it over pci, and doing just about everything. when people contrast wayland versus X as wayland compositors needing to do so much, i can't help but chuckle, because it feels like the kernel does >50% of what X used to have to do itself; it's a much simpler world, using the kernel's built-in abstractions, rather than being multiple stacked layers of abstractions (kernels + X's own).
it means that the task of writing the display-server / compositor is much much much simpler. it's still hard! but the kernel is helping so much. there's an assumed base of having working GPU drivers!
author appears to super know their stuff. alas the FOSDEM video they link to is not loading for me. :(
one major question, since this is a protocol, how viable is it to decompose the window management tasks? rather than have a monolithic window manager, does this facilitate multiple different programs working together to run a desktop? not entirely sure the use case, but a more pluggable desktop would be interesting!
>i don't think it has a huge impact on the discussion here. but this is such a key difference versus X, that i think is hugely under-told: Wayland compositors all rely on lots of kernel facilities to do the job, where-as X is basically it's own kernel, has origins where it effectively was the device driver for the gpu, talking to it over pci, and doing just about everything. when people contrast wayland versus X as wayland compositors needing to do so much, i can't help but chuckle, because it feels like the kernel does >50% of what X used to have to do itself; it's a much simpler world, using the kernel's built-in abstractions, rather than being multiple stacked layers of abstractions (kernels + X's own).
Are you an AI bot? Modern X11 server using DRM are more than 20 years old. You are talking about how X11 servers worked in the 90's
Yes exactly. DRM exists, but there's still what I called the X "kernel", all of it's heavyweight abstractions.
To the previous a-hole, frak you: not an AI. That's rude as frak. Also, you manage to be incredibly wrong. Even an AI wouldn't overlook such an obvious error; maybe it'd be better to have it replace you. So rude dude! Behave!
> Although, I do not know for sure why the original Wayland authors chose to combine the window manager and Wayland compositor, I assume it was simply the path of least resistance.
Although I'm not sure if it was the least resistance per se (as a social phenomenon), but just that it's an easier problem to tackle. Or maybe the authors means the same thing.
(That and the remote access story needs to be fixed. It just works in X11. Last time I tried it with a system that had 90 degree display orientation, my input was 90 degrees off from the real one. Now, this is of course just a bug, but I have a strong feeling that the way architecture Wayland has been built makes these kind of bugs much easier to create than in X11.)
> Although, I do not know for sure why the original Wayland authors chose to combine the window manager and Wayland compositor, I assume it was simply the path of least resistance.
Simple example of how impactful this separation has been for me.
I don't really get why would it be a good idea to somehow mandate a specific architecture design from the standard.
Every "flexible" API turns into a leaky mess unless someone is paid to write the dullest test suite in existance, and nobody is. Mandating one design is ugly, but pretending composition is free is a fairy tale.
I'm not anti-Wayland and I think X11 has enough issues that it's worth transitioning over to something better but this is a critical weakness in Wayland's design.
As a concrete example, Emacs' EXWM package works by implementing an X11 client library in Emacs Lisp, then using it to talk to the X server (which is a separate process, so this works fine) and telling it how to position windows.
Whereas on Wayland, this is not possible without re-implementing a standalone compositor process, because otherwise architecturally it doesn't work. Emacs can't both do the drawing and be drawn.
So it is architecturally possible (but infeasible in plain Emacs Lisp).
For river (the thing this article is about) I wrote an Emacs WM, but also opted for a dynamic module for the Wayland protocol parts: https://code.tvl.fyi/tree/tools/emacs-pkgs/reka
This one could technically be written in plain Emacs Lisp, but I'm happy to use something that already has all the XML codegen stuff for Wayland figured out. Dynamic modules work pretty well, fwiw.
It's not easy and the major compositors (Gnome, KDE) are NOT wlroots based, making this point mostly moot anyway.
This protocol at least has a chance of using a custom WM with an advanced compositor (which wlroots is not).
I'm glad River is trying to create a bigger base here; this is way cool. And it sort of proves the value of Wayland: someone can just go do that. Someone can just make a generic compositor/display-server now, with their own new architecture and plugin system, and it'll just work with existing apps.
We were so locked in to such a narrow limited system, with it's own parallel abstraction layer to what the kernel now offers (that didn't exist when X was created). It's amazing that we have a chance for innovation and improvement now. The kernel as a stable base of the pyramid, wlroots/sway as a next layer up, and now River as a higher layer still for folks to experiment and create with. This could not be going better, and there's so much more freedom and possibility; this is such a great engine for iteration and improvement.
https://news.ycombinator.com/newsguidelines.html
Wayland in general had a rather cavalier approach to doing away with things that X users take for granted, like, well, making screenshots. Eventually, under pressure, those in charge agreed that these features are actually very important for real users, so implementations appeared. It's an understandable way to discover the minimal usable subset of features, but the process of it is a bit frustrating for the early adopters.
Indeed - implementations, plural. Incompatible with each other, naturally.
Sure, X11 has warts but I can make it do basically anything I want. Wayland seems like it will always have too much friction to ever consider switching.
Furthermore, getting stuff like VRR on Wayland working is way easier than X.org. And, Wayland also supports HDR.
There's a type of input called "DeviceEvent" which is a bit lower level than "Window event". It also occurs even if the window isn't "active".
Windows and X11 support this, but Wayland doesn't except for mouse movement. I noticed my program stopped working on Linux after I updated it. Ended up switching to Window Events, but still kind of irritating.
X11 can't do high refresh rates every time that I've tried to do so.
That’s not a reason to do it of course, for me the driver was support for multiple monitors with different scaling requirements.
However if you really really really wanna side step this you can look at keyd - https://github.com/rvaiya/keyd
A project that has a daemon run in the background as a root service and that can provide an appropriate shim to pass key strokes to anything you want.
And just to be clear the appropriate secure model is to have a program request to register a "global" hot key and then the compositor passes it to the appropriate program once registered. This is already a thing in KDE Plasma 6 and works just fine.
Separating the compositor and window manager feels like one of those ideas that seems obvious in hindsight, but the protocol/state-machine design here shows why it took real work to make it practical.
Lowering the barrier for writing Wayland window managers without forcing everyone to build a full compositor seems like a big win.
i'm a little thrown, because the Wayland diagram doesn't feel quite right. the compositor does lie between the kernel and the apps, but IIRC the apps have their own graphics buffers from the kernel that they are drawing into directly. the compositor then composites them together. to me, that feels more like the kernel is at the center of the diagram here: the wayland compositor is between the kernel and the output / input.
i don't think it has a huge impact on the discussion here. but this is such a key difference versus X, that i think is hugely under-told: Wayland compositors all rely on lots of kernel facilities to do the job, where-as X is basically it's own kernel, has origins where it effectively was the device driver for the gpu, talking to it over pci, and doing just about everything. when people contrast wayland versus X as wayland compositors needing to do so much, i can't help but chuckle, because it feels like the kernel does >50% of what X used to have to do itself; it's a much simpler world, using the kernel's built-in abstractions, rather than being multiple stacked layers of abstractions (kernels + X's own).
it means that the task of writing the display-server / compositor is much much much simpler. it's still hard! but the kernel is helping so much. there's an assumed base of having working GPU drivers!
author appears to super know their stuff. alas the FOSDEM video they link to is not loading for me. :(
one major question, since this is a protocol, how viable is it to decompose the window management tasks? rather than have a monolithic window manager, does this facilitate multiple different programs working together to run a desktop? not entirely sure the use case, but a more pluggable desktop would be interesting!
Are you an AI bot? Modern X11 server using DRM are more than 20 years old. You are talking about how X11 servers worked in the 90's
To the previous a-hole, frak you: not an AI. That's rude as frak. Also, you manage to be incredibly wrong. Even an AI wouldn't overlook such an obvious error; maybe it'd be better to have it replace you. So rude dude! Behave!
It's vastly deeper than what Wayland does.