News: 0001656477

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

([Intel] 6 Hours Ago New Intel 64-bit Mode For GPUs)


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". [1]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 [2]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.

[3]

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 [4]Mesa already treating Nova Lake S / U / H / HX variants as stable on their open-source Linux graphics driver stack.



[1] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/43926

[2] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/43521

[3] https://www.phoronix.com/image-viewer.php?id=2026&image=nvlp_64bit_patches_lrg

[4] https://www.phoronix.com/news/Intel-Mesa-Nova-Lake-Stable



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