search for: drm_tegra_submit_wait_syncobj

...should use an FD. Doesn't this mean we can cover this by just adding a flag that marks the fence as being a handle or an FD? Do we have situations where we want an FD *and* a handle returned as result of the job submission? For the above it would suffice to add two additional flags: #define DRM_TEGRA_SUBMIT_WAIT_SYNCOBJ (1 << 2) #define DRM_TEGRA_SUBMIT_EMIT_SYNCOBJ (1 << 3) which would even allow both to be combined: DRM_TEGRA_SUBMIT_WAIT_SYNCOBJ | DRM_TEGRA_SUBMIT_EMIT_FENCE_FD would allow the job to wait for an internal syncobj (defined by handle in the fence member) and return a fence (as FD i...

...if the pre-Tegra124 GPU is capable of it). But you're right, might be a good idea to plan for this anyway since it isn't really complicated and we still have a few reserved bits left. > > For the above it would suffice to add two additional flags: > > > > #define DRM_TEGRA_SUBMIT_WAIT_SYNCOBJ (1 << 2) > > #define DRM_TEGRA_SUBMIT_EMIT_SYNCOBJ (1 << 3) > > > > which would even allow both to be combined: > > > > DRM_TEGRA_SUBMIT_WAIT_SYNCOBJ | DRM_TEGRA_SUBMIT_EMIT_FENCE_FD > > > > would allow the job to wait for an...

...er with the drm_syncobj is that you will want to handle an array of in/out fences, as userspace will pass in an array of VkSemaphore (or whatever) rather than compute a singular dma_fence_array by merging. > For the above it would suffice to add two additional flags: > > #define DRM_TEGRA_SUBMIT_WAIT_SYNCOBJ (1 << 2) > #define DRM_TEGRA_SUBMIT_EMIT_SYNCOBJ (1 << 3) > > which would even allow both to be combined: > > DRM_TEGRA_SUBMIT_WAIT_SYNCOBJ | DRM_TEGRA_SUBMIT_EMIT_FENCE_FD > > would allow the job to wait for an internal syncobj (defined by handle...

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