Update wayland information
fix QT_QPA_PLATFORM setting typo
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Wayland is a communication protocol that specifies the communication between a display server and its clients. A display server using the Wayland protocol is called a Wayland compositor, because it additionally performs the task of a compositing window manager.
The aim of Wayland is replacing the X Window System (Also known as X11, or Xorg) with a modern, secure, and simpler windowing system. As part of its efforts, the Wayland project also develops a reference implementation of a Wayland compositor called Weston. Major desktops such as KDE Plasma and GNOME have implemented their own Wayland compositors.
- Testing Wayland
- Supported environments
- Partially supported
- Why is Wayland necessary?
- Applications can't share information with each other... so how do I copy and paste?
- I'm accustomed to running various programs (e.g. synaptic) as root in my X session. How will this work under Wayland?
- I run various programs over the network, e.g. through ssh X11 forwarding, or xhost. How will this work under Wayland?
- I share monitors between systems using x2x. How will this work under Wayland?
- Further reading
It's important firstly to check your hardware and make sure it's compatible with your choice of desktop. The divide right now is strictly between two buffer APIs, GBM and EGLStreams. NVIDIA GPUs using the proprietary driver support EGLStreams, while all other graphics cards and driver combinations support GBM. A Wayland compositor needs to explicitly support one or both of these APIs in order to function.
As it stands, GNOME (using Mutter) supports both GBM and EGLStreams well. KDE Plasma (using KWin) supports GBM in all versions, and EGLStreams since Plasma 5.16. All other compositors only support GBM and will not function with the proprietary NVIDIA driver in use.
The Wayland session is built into GNOME and it should be an option in your display manager simply by having GNOME installed.
KDE Plasma requires the non-default plasma-workspace-wayland package to be installed. This is often enough for basic functionality, however you are recommended to read the detailed wiki section for KDE on Wayland, especially if you are using an NVIDIA GPU.
GTK3 and Qt 5 applications using the system libraries should default to Wayland automatically. Some that use statically-linked versions of these, or which explicitly disable Wayland support for various reasons (e.g., KeePassXC), will require special flags or environment variables to be set.
Applications using X11 will work fine in Wayland via the Xwayland compatibility layer, however there may be input issues or other bugs introduced. When possible, using an application in its native Wayland mode is preferred.
The GDK_BACKEND environment variable, when set to "wayland", will forcibly run a GTK3 application with the Wayland backend. Similarly, setting the environment variable to "x11" will force it to run with the X11 backend (useful for forcing applications to use Xwayland that have compatibility issues when operating in their native Wayland mode).
The qtwayland5 package will install the relevant platform plugin allowing Wayland apps to run natively with Qt.
You are recommended to set the environment variable QT_QPA_PLATFORM to "wayland;xcb" which will have applications prefer Wayland only use X11 as a fallback. You can, of course, set this to also be specifically either "wayland" or "xcb" if you want to force one.
The -platform wayland flag can also be used as a simpler means to force most Qt applications to use the Wayland backend.
For games, applications, or other software that uses SDL2 as a toolkit, set the SDL_VIDEODRIVER environment variable to "wayland". Note that doing this on a system-wide basis isn't recommended, as many proprietary applications use statically-linked versions of SDL2 that are older and may break when forcing the usage of Wayland.
GDM (GNOME Display Manager) will automatically use Wayland when supported, except when using the proprietary NVIDIA driver, in which case it will fall back to X11 due to instability.
To use the X11 backend by default, uncomment the WaylandEnable=false line in the /etc/gdm3/daemon.conf file.
Wayland support for SDDM itself is in progress, currently it uses X11 by default everywhere. SDDM is still capable of starting a Wayland session for a desktop however.
There is little hope of LightDM obtaining native Wayland support, however it can still start a Wayland session for a desktop.
To test Wayland, you will need to have a compatible compositor installed. A Wayland compositor combines the roles of the X window manager, compositing manager and display server. Most major desktops support Wayland well, but for testing purposes, weston is the reference implementation of the concept.
You can test Weston directly from a regular X session simply by installing the weston package and then running weston in a terminal session. This will start a Wayland window in your regular X session where you can test things.
You can also test GNOME's mutter Wayland compositor directly:
mutter --nested --wayland
Then further Wayland clients will show up in that window. Try, for example, starting gnome-terminal.
- GNOME 3.20+ (Wayland used by default in Debian 10 and newer, older versions use Xorg by default)
KDE Plasma 5.4+ (Xorg is used by default, Wayland requires the plasma-workspace-wayland package to be installed)
- Qt 5
- GTK+ 3.20+
- SDL 2.0.2+
- GLFW 3.2
Fireplace (no Debian package yet)
Emacs: because Emacs is not a real GTK apps, it still talks with X11 and therefore will use XWayland
Vim: similar (819954)
For backwards compatibility, any X program will run under Xwayland. Install the xwayland package if it wasn't brought in by your desktop of choice.
If using the Weston compositor add these lines to ~/.config/weston.ini
[core] xwayland=true [xwayland] path=/usr/bin/Xwayland
The security and performance improvements of Wayland are not be obtained with Xwayland.
Xresources won't load
This is a known issue. Back in 2015, it was decided that the resources were too slow to load and that was dropped from the main GNOME session, see Redhat's bugzilla for more information.
Workaround: run this by hand or setup something to start it up automatically on session login.
xrdb -load .Xsession
Why is Wayland necessary?
Wayland allows better isolation between processes: one window cannot access resources from, or inject keystrokes into, another window.
Wayland also has the potential to be faster, by reducing the amount of code between the processes and the hardware, by delegating lots of things to the processes themselves.
See also the Wayland FAQ for more information.
Applications can't share information with each other... so how do I copy and paste?
The clipboard should work like normal between X11 and Wayland applications in most sessions, however it's up to the Wayland compositor to negotiate this.
There are plans to allow X11 applications running as root to use XWayland but native Wayland applications need to be restructured into a GUI part and a root part.
SSH X11 forwarding works like before for X11 applications via XWayland. Native Wayland applications are not forwarded.
I share monitors between systems using x2x. How will this work under Wayland?
Screen sharing with Wayland is in the preliminary stages. Currently, the most progress has been made in Chromium where pipewire and xdg-desktop-portal can be leveraged for screen sharing in WebRTC. With these packages installed, WebRTC PipeWire support must still be enabled in the Chromium flags, as can be found by entering in the address bar: chrome://flags/#enable-webrtc-pipewire-capturer