Mesa 22.2 Adds Option To Enable Compute Engine For Intel Arc Graphics

With the in-development Linux 5.19 kernel there is compute engine support for DG2/Alchemist graphics now exposed to user-space. Besides the Intel OpenCL Runtime / oneAPI Level Zero preparing to make use of that compute engine support, patches merged today to Mesa 22.2 also allow enabling the DG2-class Arc Graphics compute support within the OpenGL/Vulkan drivers.

While the DG2/Alchemist graphics enablement within Intel's open-source Linux graphics driver stack has been going on for a while, the patches for enabling compute support with the Arc Graphics discrete GPUs was only picked up for the Linux 5.19 merge window while the graphics support has been settling for the past number of kernel cycles.

With the Mesa side support for using the i915 kernel driver's compute user-space interface for DG2/Alchemist, it's not being enabled by default at this time. With today's Git code the new INTEL_COMPUTE_CLASS=1 environment variable needs to be set for using the compute engine on these forthcoming graphics cards.

Coincidentally these Mesa patches merged on the same day as the Intel Arc A380 graphics card launching in China.

The INTEL_COMPUTE_CLASS=1 environment variable with Mesa 22.2 when running on Linux 5.19+ will allow the Iris Gallium3D driver on Alchemist to use the compute engine for compute dispatches. In the Vulkan world with the Intel "ANV" driver it will advertise Vulkan compute queue support.

See the merged MR for details. Hopefully it won't be long before this environment variable is just droped and Mesa will make use of the Alchemist compute engine interface by default.