Mesa 26.3 Preps For Intel Nova Lake P's New 64-bit GPU Mode

Merged overnight for Mesa 26.3 are changes to Intel's graphics compiler code for supporting a new 64-bit shader addressing mode. It turns out with upcoming Nova Lake P graphics will be a big fundamental change. Catching me by surprise this morning were 49 patches hitting Mesa Git for the Intel shader compiler code and ANV Vulkan driver for "efficient 64-bit". The merge request of what's now in Git for Mesa 26.3 doesn't elaborate too much but it's an alternate version of this earlier closed PR from earlier in August. That pull request went on to explain the new 64-bit mode with upcoming Intel graphics: "Up to GFX35, we had to program STATE_BASE_ADDRESS with 64-bit base addresses for some heaps. Then, when a shader needed to access a specific buffer, it would use a 32-bit address that HW would add to the base address of that buffer's heap type to get the full 64-bit address. However, that is changing on GFX35+, 64-bit addresses are now supported by EUs. NVL-P, as the first GPU with 64-bit support, has the option to select the addressing mode with a bit in STATE_BASE_ADDRESS, but newer GPUs will only support 64-bit." So with Nova Lake P specifically, 64-bit addresses are now supported by its integrated Xe3P graphics and Intel's first GPU with 64-bit support. Newer post-Nova-Lake-P Intel GPUs will only support 64-bit mode. This Mesa graphics driver code is getting things ready. The merged code is for the Intel compiler code and ANV Vulkan driver efficient 64-bit state emission while a follow-up pull request will prep the Intel Iris Gallium3D (OpenGL) driver support. The individual patches mostly lack any patch messages so they don't elaborate further on this "efficient 64-bit" mode coming with Nova Lake P and beyond. We'll presumably learn more about the NVL-P graphics changes once the Core Ultra Series 4 hardware launches in the months ahead. This 64-bit change also doesn't appear to affect other Nova Lake variants with Mesa already treating Nova Lake S / U / H / HX variants as stable on their open-source Linux graphics driver stack.