Intel Posts Latest DG2/Alchemist Linux Patches In Requiring 64K Page Size Handling

While Linux 5.15 brings very early bits around DG2/Alchemist graphics card support, further work is needed to bring it into usable shape for end-users. The latest new patch series to be posted came out today with more driver changes needed around local device memory handling for DG2.

New with DG2 is that the hardware only is supporting 64K page sizes and larger. The i915 device memory for DG2 and future discrete graphics can only support 64K or larger for the GTT page size even if using say 4K for the kernel page size on x86_64 systems.

In addition to DG2 enforcing at least a 64K page size for its dedicated video memory, DG2 brings a new "flat CCS" approach to its Compression Control State (CCS) metadata. Rather than storing that compression control state information in a separate region of memory as with current Gen12 graphics, beginning with DG2 is the new "flat CCS" with a flat indexed region of memory for storing the state information.

These two low-level changes to how DG2 deals with local memory led to these 14 patches out today with the latest i915 driver restructuring.

As part of the series they have also begun documenting their path to DG2/Alchemist upstreaming and the changes impacting the user-space API. The first Intel ARC Alchemist/DG2 graphics cards are expected to launch in early 2022 and we'll see how the at-launch support is on Linux when the time comes.