Wayland gets DRM lease protocol support to help VR on Linux

Another tick in the box for Wayland to eventually properly replace X11 for all workloads, as the work on DRM lease protocol support aimed at VR has been merged in.

From the merge request that was open for a few months here's how they explain it:

DRM leasing is a feature which allows the DRM master to "lease" a subset of its DRM resources to another DRM master via drmModeCreateLease, which returns a file descriptor for the new DRM master. We use this protocol to negotiate the terms of the lease and transfer this file descriptor to clients.

In less DRM-specific terms: this protocol allows Wayland compositors to give over their GPU resources (like displays) to a Wayland client to exclusively control.

The primary use-case for this is Virtual Reality headsets, which via the non-desktop DRM property are generally not used as desktop displays by Wayland compositors, and for latency reasons (among others) are most useful to games et al if they have direct control over the DRM resources associated with it. Basically, these are peripherals which are of no use to the compositor and may be of use to a client, but since they are tied up in DRM we need to use DRM leasing to get them into client's hands.

This work has been ongoing for years overall, with the needed Vulkan extension only landing back in June this year with the Vulkan 1.2.182 spec update.

For this to actually be properly usable though it needs wider testing, and it also needs support to be merged into the various Wayland compositors. Currently it's in staging, to eventually make it into a stable update of the Wayland protocols. So we're still a little while away before it's going to be fully supported across all the various distributions. Good news though, since Wayland is gradually becoming the default and having good VR support is needed.