Runtime Configuration

The platform provides utilities for changing the configuration and runtime parameters.

The full source code to the NVIDIA implementation of Weston is in:

drive-linux/samples/wayland/weston

The NVIDIA implementation of Weston uses the Direct Rendering Manager (DRM) backend, found in the target filesystem at:

/usr/local/lib/weston/drm-backend.so

There are two implementations of the DRM display backend. One is implemented on the Linux KMS. The other is implemented on top of the EGLOutput series of extensions.

During the Weston startup, Weston creates an OpenGL ES EGLStream producer, if option use-egldevice is enabled. Weston then creates EGLOutput. EGLOutput is the EGLStream consumer that passes all the output frames from Weston to the display, For more information, see EGLOutput Specifications. If use-egldevice is not enabled, the output method switches to drm/kms.Wayland buffer sharing between EGL clients and Weston is implemented using EGLStreams. The EGL client creates an EGLStream producer and binds the EGLStream file descriptor to wl_buffer through the Wayland protocol. Weston queries the EGLStream file descriptor from wl_buffer through a query of EGL_WAYLAND_BUFFER_WL to eglQueryWaylandBufferWL(). This functionality is provided by the EGL_WL_bind_wayland_display extension.

Wayland buffer sharing also supports dma-buf sharing based on the linux-dmabuf-unstable-v1-protocol protocol. For more information, see Weston dma-buf Support.

The NVIDIA EGL implementation tries to detect what platform it is running on at runtime (e.g., Wayland, etc.). It is possible to bypass this detection by setting the EGL_PLATFORM environment variable. For Wayland, this variable must be set to "wayland". And do not set the environment variable DISPLAY in case of the wayland platform. If DISPLAY is set, you are assumed to be running X11.