The Latest NVIDIA EGLStreams Wayland Backend Code Under Review For KDE/KWin

Back in November is when NVIDIA announced they were developing an EGLStreams-based back-end for KDE's KWin so the KDE Wayland session could run with their proprietary graphics driver similar to GNOME's EGLStreams support. That latest code is now under review.

It's been quiet on the public mailing list since they announced their intentions to develop this EGLStreams KWin back-end that would in effect just benefit their proprietary Linux graphics driver due to the other drivers/vendors with their open-source drivers supporting GBM for buffer management. NVIDIA's long talked about new "Unix device memory allocator" API also has yet to materialize, leaving NVIDIA to developing EGLStreams back-ends for the different Wayland compositors in order to gain ground.

This week Erik Kurzinger of NVIDIA posted the initial EGLStreams back-end for review with KWin.

This is the initial implementation of a DRM backend based on the EGLDevice, EGLOutput, and EGLStream extensions, supporting NVIDIA graphics hardware using their proprietary driver. The new backend will be used if the environment variable KWIN_DRM_USE_EGLDEVICE is set. On initialization, it will attempt to create an EGLDevice based on the DRM device currently in use and create EGLOutputs and EGLStreams for any attached displays. These are used to control presentation of the final composited frame. Additionally, it will register the wl_eglstream_controller Wayland interface so that native EGL windows created by clients can be attached to an EGLStream allowing buffer contents to be shared with the compositor as a GL texture.

Currently, this backend is incompatible with atomic modesetting and hardware cursors. Support for both is planned as future work, as is integration with the autotesting framework and support for remote access.

At this time there is a known bug in the NVIDIA driver where plasmashell's tool-tip window will appear blank if it is resized. A fix is in development and should be present in an upcoming driver release.

We'll see how this review process goes and if NVIDIA can get their new back-end merged in the months ahead for allowing a KDE Wayland experience with NVIDIA graphics, short of using the Nouveau driver.