Intel Mesa Driver Code Working To Split Off Old Broadwell "Gen8" Graphics Code

Intel's Iris Gallium3D driver for modern OpenGL support works on hardware going back to old Broadwell processors with "Gen8" integrated graphics as does the HasVK Vulkan driver for Haswell/Broadwell. But in allowing to focus on the common Skylake "Gen9" graphics and newer/future Intel graphics architectures, pending Mesa code is working to split-off that old Broadwell/Gen8 code. The Gen8 support will continue to be in-tree but separated from the rest of the compiler code so that the code can continue to be improved for newer Intel hardware without risking regressions/breaking those still on Broadwell era processors.

Intel graphics engineer Caio Oliveira has been leading the effort to split-off the Gen8 (Gfx8) compiler code into a separate module for use by the relevant OpenGL/Vulkan drivers. It's effectively taking a snapshot of the current state of the driver code so it can live off in its own segmented land. Then Gfx9+ graphics compiler code can be maintained and improved upon moving forward without worrying about that older hardware support.

Oliveira explained in a pending merge request:

"The key goal here is allow us to make more aggressive changes for the compiler that target the anv and iris drivers without potentially breaking the older Gfx version drivers. Our test coverage for those is way more restricted. This is consistent with the original splitting of the drivers (crocus hasvk) themselves.

Picking Gfx9+ minimizes the combinations of drivers and compilers, and also synchronizes with anv. If we ever do another driver split, I think is a good idea to walk them all together."

Some elements of that code restructuring have already landed while other pieces of it are still a work-in-progress. We'll see if this change-over is wrapped up in time for Mesa 24.1 for then removing the Gfx8 code.

The once fascinating Core i7 5775C Broadwell processor...

This move makes sense with Broadwell already being 11 years old... The open-source Linux graphics driver support will remain available and upstream albeit don't expect any major improvements moving forward, at least from the Intel side while occasionally there are open-source hobbyists with an itch to scratch. At the end of 2022, Intel already made end-of-life their Ice Lake through Skylake and Elkhart Lake graphics driver support. So on the Linux/open-source side it's already a better story for long-term hardware support.