NGG Appears To Be In Good Shape For RDNA 2 / RX 6000 Series

NGG (Next-Gen Geometry) ended up being fairly buggy/problematic for Navi but it looks like for the upcoming Radeon RX 6000 (RDNA 2 / Navi 2) launch that it's in better shape.

The NGG support for Navi 1x involved a lot of driver work from at times enabling it only to disable some functionality to other tweaks in avoiding hangs or other problems around it.

There still is two weeks to go until the big Navi launch but the latest open-source AMD Radeon Linux driver activity appears to indicate NGG is more reliable with the forthcoming hardware.

With this merge that hit Mesa 20.3-devel on Friday, NGG culling is now fixed for GFX10.3 (the Navi 2x targets) and is enabled by default. The NGG culling shader is optimized leading to "slightky better culling performance in some cases."

Besides enabling NGG culling by default for all GFX10.3 discrete GPU targets, the change also interestingly enables NGG for all Navi 1x PRO graphics cards as well. For the PRO variants it seems NGG culling is more reliable while remaining disabled for the common consumer Navi cards.

Given this optimization and other work in recent weeks, it's looking like Mesa 20.3 will be a better target for early Radeon RX 6000 series support than the first-cut hardware enablement in Mesa 20.2. Mesa 20.3.0 will debut as stable around early December albeit very easy to obtain in Git/development form on most distributions. LLVM 11.0+ and Linux 5.9+ are the other key components for the next-generation Navi support.