[Nouveau] [PATCH 0/3] drm/tegra: Add support for fence FDs

[Chris Wilson]

Quoting Thierry Reding (2018-01-11 22:22:46)
> From: Thierry Reding <treding at nvidia.com>
> 
> This set of patches adds support for fences to Tegra DRM and complements
> the fence FD support for Nouveau. Technically this isn't necessary for a
> fence-based synchronization loop with Nouveau because the KMS core takes
> care of all that, but engines behind host1x can use the IOCTL extensions
> provided here to emit fence FDs that in turn can be used to synchronize
> their jobs with either the scanout engine or the GPU.

Whilst hooking up fences, I advise you to also hook up drm_syncobj.
Internally they each resolve to another fence, so the mechanics are
identical, you just need another array in the uABI for in/out syncobj.
The advantage of drm_syncobj is that userspace can track internal fences
using inexhaustible handles, reserving the precious fd for IPC or KMS.
-Chris