EGL_ANDROID_native_fence_sync Patches For Mesa

Rob Clark on Friday sent out the patches for implementing the EGL_ANDROID_native_fence_sync extension within Mesa's EGL and Gallium3D code.

The Red Hat developer explained, "This extension provides support for native fence fd's (file descriptors) for the GPU. In a similar way to dma-buf fd's, which provide a reference-counted userspace handle to buffers which can be shared across drivers and across processes, native fence fd's provide a reference-counted userspace handle to fences which can be shared across drivers and across processes. This extension is already in use on android, and should be useful in other environments."

Those wanting to better understand this extension can see the Khronos.org registry.

In terms of the fencing support on the DRM kernel driver side, "The kernel patches for freedreno (drm/msm) are upstream (v4.9) and the libdrm patches are in v2.4.72. Kernel patches for drm/virtio are in flight (so corresponding gallium patch is not ready to push). Kernel plus libdrm plus mesa patches for i965 are in flight."

Implementing this extension is around 500 lines of code. More details via the Mesa-dev list.