Status of Wayland support in NVIDIA drivers

Aaron Plattner, one of the lead developers of NVIDIA’s proprietary drivers, posted the status of Wayland protocol support in the R515 driver testing branch, for which NVIDIA provided the source code for all kernel-level components. It is noted that in a number of areas support for the Wayland protocol in the NVIDIA driver has not yet reached parity with support for X11. At the same time, the lag is associated with both problems in NVIDIA driver, as well as with the general limitations of the Wayland protocol and composite servers based on it.

Driver Limits:

• The libvdpau , which allows hardware acceleration mechanisms for post-processing, compositing, displaying and decoding video, lacks built-in support for Wayland. The library also cannot be used with Xwayland.
• Wayland and Xwayland are not supported in the NvFBC (NVIDIA FrameBuffer Capture) library used for screen capturing.
• The nvidia-drm module does not report variable refresh rate features such as G-Sync, which prevents them from being used in Wayland-based environments.
• In Wayland-based environments, output to virtual reality screens, for example, supported by the SteamVR platform, is not available due to the inoperability of the DRM Lease , which provides the DRM resources necessary to form a stereo image with different buffers for the left and right eyes when displayed on virtual reality helmets.
• Xwayland does not support the EGL_EXT_platform_x11 .
• The nvidia-drm module does not support the GAMMA_LUT, DEGAMMA_LUT, CTM, COLOR_ENCODING and COLOR_RANGE properties, which are necessary for full support of color correction in composite managers.
• When using Wayland, the functionality of the nvidia-settings utility is limited.
• With Xwayland in GLX, drawing the output buffer to the screen ( front-buffer ) does not work when double buffering.

Limitations of the Wayland protocol and composite servers:

• Features such as stereo out, SLI, Multi-GPU Mosaic, Frame Lock, Genlock, Swap Groups, and advanced display modes (warp, blend, pixel shift, and YUV420 emulation) are not supported in the Wayland protocol or composite servers. Apparently, to implement such functionality, it will be necessary to create new EGL extensions.
• There is no commonly accepted API that allows Wayland composite servers to power down video memory via PCI-Express Runtime D3 (RTD3).
• Xwayland lacks a mechanism that can be used in the NVIDIA driver to synchronize application rendering and screen output. Without such synchronization, under some circumstances, the appearance of visual distortions is not excluded.
• Wayland composite servers do not support screen multiplexers (mux) used on laptops with two GPUs (integrated and discrete) to directly connect a discrete GPU to an integrated or external screen. In X11, the “mux” screen can automatically switch when a full-screen application outputs via the discrete GPU.
• Indirect rendering through GLX does not work in Xwayland, since the implementation of the GLAMOR 2D acceleration architecture is not compatible with NVIDIA’s EGL implementation.
• overlays are not supported in GLX applications running in Xwayland-based environments Hardware .