Linux may provide independent video memory for DG2 graphics cards

The mailing list shows that Intel has submitted a patch to enable device memory support for its DG2 graphics card. The DG2 graphics card is now code-named “Alchemist“, which is the first generation product of the new high-performance graphics card brand Intel Arc launched by Intel. Since July, Intel has submitted several rounds of patches for the graphics card, including the introduction of DisplayPort 2.0 related support, etc. Due to the previous preparations for introducing device local memory in the DG1 phase, the patch submitted this time mainly deals with the Gen12.5+ platform with device memory.

The changes include:
Intel Arc
1. Minimum page size has been changed to 64KB.
2. Compression control state (CCS) moved from user-space manages AUX page tables to flat indexed region of memory. This Flat index memory is referred as Flat CCS.
3. Due to different page sizes of LMEM(64K) and SMEM(4K), a mix of LMEM and SMEM pages are not supported in a single page table.
In addition, Intel stated that the next work is to deal with the plane CCS during the migration of the buffer from the system to the device memory. If nothing happens, these patches will be merged into the mainline during the Linux 5.16 cycle.