39 Using Wayland and Weston
Wayland is a computer display server protocol that provides a method for compositing window managers to communicate directly with applications and video hardware and expects them to communicate with input hardware using other libraries. Using Wayland with supporting targets can result in better control over graphics frame rendering than an application might otherwise achieve.
The Yocto Project provides the Wayland protocol libraries and the
reference Weston
compositor as part of its release. You can find the integrated packages
in the meta
layer of the Source Directory.
Specifically, you
can find the recipes that build both Wayland and Weston at
meta/recipes-graphics/wayland
.
You can build both the Wayland and Weston packages for use only with targets that accept the Mesa 3D and Direct Rendering Infrastructure, which is also known as Mesa DRI. This implies that you cannot build and use the packages if your target uses, for example, the Intel Embedded Media and Graphics Driver (Intel EMGD) that overrides Mesa DRI.
Note
Due to lack of EGL support, Weston 1.0.3 will not run directly on the emulated QEMU hardware. However, this version of Weston will run under X emulation without issues.
This section describes what you need to do to implement Wayland and use the Weston compositor when building an image for a supporting target.
39.1 Enabling Wayland in an Image
To enable Wayland, you need to enable it to be built and enable it to be included (installed) in the image.
39.1.1 Building Wayland
To cause Mesa to build the wayland-egl
platform and Weston to build
Wayland with Kernel Mode Setting
(KMS)
support, include the “wayland” flag in the
DISTRO_FEATURES
statement in your local.conf
file:
DISTRO_FEATURES:append = " wayland"
Note
If X11 has been enabled elsewhere, Weston will build Wayland with X11 support
39.1.2 Installing Wayland and Weston
To install the Wayland feature into an image, you must include the
following
CORE_IMAGE_EXTRA_INSTALL
statement in your local.conf
file:
CORE_IMAGE_EXTRA_INSTALL += "wayland weston"
39.2 Running Weston
To run Weston inside X11, enabling it as described earlier and building a Sato image is sufficient. If you are running your image under Sato, a Weston Launcher appears in the “Utility” category.
Alternatively, you can run Weston through the command-line interpretor (CLI), which is better suited for development work. To run Weston under the CLI, you need to do the following after your image is built:
Run these commands to export
XDG_RUNTIME_DIR
:mkdir -p /tmp/$USER-weston chmod 0700 /tmp/$USER-weston export XDG_RUNTIME_DIR=/tmp/$USER-weston
Launch Weston in the shell:
weston