wayland-protocols scope and governance

Hi all, I'd like to open up a discussion on enlarging wayland-protocols to a wider audience, with a better definition of what it contains. Currently, wayland-protocols is a relatively small set of protocols which were either grandfathered in from Weston, or a semi-opinionated set of protocols that someone thinks is 'good'. The original intent was to provide a set of 'blessed' desktop protocols which 'everyone' would probably implement in order to provide a coherent Wayland environment. To some extent - xdg-shell, dmabuf, xdg-output, viewporter - this succeeded. For some others, it failed badly - the input protocols no-one likes or has implemented, necessitating Dorota's rewrite. The elephant in the room is extensions like layer-shell and some of the related extensions to build a desktop environment from a set of disparate clients using generic APIs. Personally I think the experience of X11 shows it's only designing for pain, and this is the general position of wayland-protocols at the moment. But on the other hand, those protocols aren't going away, they are in use, and having them developed in a separate siloed community is doing us all a disservice, since neither hand fully knows what the other is doing. Even if we don't agree on the fundamentals of the protocol, we could at least discuss it and try to point out some pitfalls and make some suggestions for improvement. A related issue is that it's hard for both application and compositor authors to figure out what to do. There is no good 'big picture' on how these protocols fit together, nor can people figure out which of the competing proposals they should be using if they want to write an application running on a given compositor, nor can compositor authors figure out what apps want them to support. Depending on who happens to be paying attention to the particular forum the question is asked, they might get very different answers, depending on the point of view of who answers. My first, hopefully uncontroversial, suggestion: introduce a list of compositors / compositor frameworks, as well as clients / client frameworks, and which protocols they use and support. This would help both application and compositor authors figure out where they should invest time and effort. I suggest that we keep this lightweight: have a registry of compositors / compositor frameworks / toolkits / clients, each with a couple of named people who can speak authoritatively for that project. We could then allow each project to declare its support (or otherwise) for any extension: will not ever implement, implementation not planned, no opinion or N/A, implementation planned, implemented but use not recommended (or limited/stubbed), implemented and recommended. This list would be machine-parseable (XML, JSON, YAML, whatever is easiest to fit), with a GitLab CI pipeline used to generate a https://wayland.freedesktop.org/protocols/ website on every push, which gave both a per-extension and a per-project support table. And some more readable docs. I think this would be a really good entry point and clear up a lot of confusion. As a strawman list of projects to begin with (I'm sure there are others): - compositors and compositor frameworks: Chromium (Exosphere), Enlightenment, KWin, Mutter, Smithay, Sway, Weston/libweston, wlroots - toolkits: EFL, GTK, Qt - media: GStreamer, Kodi, VLC, XBMC - other clients: Chromium (client), Firefox, Mesa (EGL/Vulkan) My second suggestion is to formalise the 'xdg' namespace. xdg extensions have been accepted or rejected by rough consensus between Enlightenment/EFL, GNOME, and KDE. That still seems reasonable enough to me, assuming that 'xdg' retains the focus of an integrated (as opposed to build-it-yourself) desktop. The IVI namespace would similarly be delegated to automotive people, and maybe we could delegate the layer_ namespace to those developers as well. My third suggestion is to formalise the 'wp' namespace, as core extensions that everyone can agree on. It doesn't mean everyone needs to implement them, but at least not have active opposition. For example, Mutter hadn't implemented wp_viewporter for the longest time, but also had no opposition to it being implemented - which wouldn't block it being a 'wp' protocol. Or Weston hasn't implemented xdg_foreign and probably won't, but I'm fine with it existing and being a common extension. On the other hand, Weston/Mutter/etc would have very strong opposition to a 'wp_randr' extension, and last I saw wlroots would have very strong opposition to wp_pointer_gestures. So those wouldn't be wp. So where does that leave other extensions? My fourth suggestion is that we look to the OpenGL/EGL/Vulkan registries: if an extension has been vetoed from the wp_ namespace, but still had support and implementations from multiple projects, that we still accept and publish it under a different namespace which makes it clear that some projects think the extension is fundamentally a bad idea, but it is also not a compositor-specific extension. Bikeshedding the prefix to use here would be welcome, as I don't have any good suggestions right now. Once we've established and codified these ground rules - with a document along the lines of Wayland's CONTRIBUTING.md - we can open up commit access to wayland-protocols, so we're not so reliant on a couple of arbitrary gatekeepers. Obviously this would be done with the expectation that those ground rules are followed - don't post a wp_ extension on a Sunday morning and then commit it in the evening with a couple of +1s because no-one objected - but we're all reasonable adults, and can treat each other reasonably without having to enforce ACLs. Does anyone have any thoughts or suggestions here? Is this a good aspiration? Is it the best way of achieving that aspiration? Cheers, Daniel