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~-[[DebianWiki/EditorGuide#translation|Translation(s)]]: English - [[fr/Wayland|Français]] -~
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= Wayland =
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Wayland is a computer protocol that specifies the communication between a display server and its clients, as well as a reference implementation of the protocol in the C programming language.

Wayland's main goal is replacing the X Window System with a modern, simpler windowing system in Linux and other Unix-like operating systems. The project's source code is published under the terms of the MIT License, a permissive free software licence.

As part of its efforts, the Wayland project also develops a reference implementation of a Wayland compositor called Weston.[7]

## If your page gets really long, uncomment this Table of Contents
## <<TableOfContents(2)>>
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.
<<TableOfContents(4)>>

== Usage ==
=== Hardware requirements ===
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.
----
=== Desktops ===
==== GNOME ====
The Wayland session is built into GNOME and it should be an
option in your display manager simply by having GNOME installed.

==== KDE ====
KDE Plasma requires the non-default DebianPkg: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#Wayland.2C_touchscreens.2C_autorotation.2C_hi-DPI|KDE on Wayland]],
especially if you are using an NVIDIA GPU.

==== Others ====
Other Wayland compositors of interest may include [[sway|Sway]]
(a near drop-in replacement for i3) and DebianPkg:enlightenment.
----
=== Applications ===
==== Introduction ====
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.

==== GTK3 ====
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).

Note that some Electron applications (Slack, Element, Discord, etc.)
may break when setting {{{GDK_BACKEND}}} to "wayland".

==== Qt 5 ====
The DebianPkg: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.

==== SDL2 ====
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.
----
=== Display Managers ===
==== GDM3 ====
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.

==== SDDM ====
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.

==== LightDM ====
There is little hope of LightDM obtaining native Wayland support,
however it can still start a Wayland session for a desktop.
----
== Testing Wayland ==
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,
DebianPkg:weston is the reference implementation of the concept.

You can test Weston directly from a regular X session simply by
installing the DebianPkg: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 DebianPkg:mutter Wayland compositor directly:

{{{
mutter --nested --wayland
}}}

Then further Wayland clients will show up in that window.
Try, for example, starting DebianPkg:gnome-terminal.
----
== Supported environments ==

Desktop environments:

 * 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 DebianPkg:plasma-workspace-wayland package to be installed)
 * Enlightenment
 * Hawaii

Toolkits:

 * Qt 5
 * GTK+ 3.20+
 * Clutter
 * SDL 2.0.2+
 * EFL
 * GLFW 3.2

Window managers:

 * DebianPkg:sway ([[https://swaywm.org/|website]], [[https://github.com/SirCmpwn/sway|Github project]]) (Will [[https://drewdevault.com/2017/10/26/Fuck-you-nvidia.html|stop]] supporting NVidia EGL/closed source driver from 1.0 onwards.)
 * [[https://github.com/Drakulix/fireplace|Fireplace]] (no Debian package yet)

== Partially supported ==

 * Emacs: because Emacs is [[http://emacshorrors.com/posts/psa-emacs-is-not-a-proper-gtk-application.html|not a real GTK apps]], it still talks with X11 and therefore will use XWayland
 * Vim: similar (DebianBug:819954)

== Unsupported ==

Desktop environments:

 * Cinnamon: [[https://github.com/linuxmint/Cinnamon/issues/5201|discussed]]
 * MATE: [[https://github.com/mate-desktop/mate-wiki/tree/master/pages/wayland.md|planned]], [[https://www.phoronix.com/scan.php?page=news_item&px=MTYwNjQ|source]] (2014), [[https://www.phoronix.com/scan.php?page=news_item&px=MATE-Usable-Wayland-Mir-Video|an update]] (2019)
 * XFCE: [[https://www.reddit.com/r/xfce/comments/4aeqda/xfce_wayland_support/|planned]]

Window managers:

 * i3: [[https://faq.i3wm.org/question/687/i3-support-for-wayland.1.html|FAQ]], [[https://www.reddit.com/r/i3wm/comments/2ucznn/any_i3_support_plans_for_wayland_in_the_neaby/|discussion]].
 * other window managers unlikely to be supported
----
== Xwayland ==

For backwards compatibility, any X program will run under Xwayland. Install the DebianPkg: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.
----
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== FAQ ==

=== 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 [[https://wayland.freedesktop.org/faq.html|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.

=== I'm accustomed to running various programs (e.g. synaptic) as root in my X session. How will this work under Wayland? ===

(In fact, DebianPkg:synaptic was [[https://tracker.debian.org/news/1037065/synaptic-removed-from-testing/|temporarily removed from buster]] because it didn't work under Wayland.)

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.

=== I run various programs over the network, e.g. through ssh X11 forwarding, or xhost. How will this work under Wayland? ===

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
DebianPkg:pipewire and DebianPkg: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}}}
----
== Further reading ==

 * [[https://wiki.archlinux.org/index.php/Wayland|Arch Linux wiki]]
 * [[https://wayland.freedesktop.org/|Wayland homepage]]
 * [[https://wayland.freedesktop.org/faq.html|Wayland FAQ]]

----

Translation(s): English - Français


Wayland

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.

Usage

Hardware requirements

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.


Desktops

GNOME

The Wayland session is built into GNOME and it should be an option in your display manager simply by having GNOME installed.

KDE

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.

Others

Other Wayland compositors of interest may include Sway (a near drop-in replacement for i3) and enlightenment.


Applications

Introduction

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.

GTK3

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).

Note that some Electron applications (Slack, Element, Discord, etc.) may break when setting GDK_BACKEND to "wayland".

Qt 5

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.

SDL2

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.


Display Managers

GDM3

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.

SDDM

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.

LightDM

There is little hope of LightDM obtaining native Wayland support, however it can still start a Wayland session for a desktop.


Testing Wayland

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.


Supported environments

Desktop environments:

  • 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)

  • Enlightenment
  • Hawaii

Toolkits:

  • Qt 5
  • GTK+ 3.20+
  • Clutter
  • SDL 2.0.2+
  • EFL
  • GLFW 3.2

Window managers:

Partially supported

Unsupported

Desktop environments:

Window managers:

  • i3: FAQ, discussion.

  • other window managers unlikely to be supported


Xwayland

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.


Troubleshooting

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


FAQ

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.

I'm accustomed to running various programs (e.g. synaptic) as root in my X session. How will this work under Wayland?

(In fact, synaptic was temporarily removed from buster because it didn't work under Wayland.)

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.

I run various programs over the network, e.g. through ssh X11 forwarding, or xhost. How will this work under Wayland?

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


Further reading


CategoryDesktopEnvironment