That was quick: Phoronix found that version 19.1 of the Mesa 3D Graphics Library will add support for fast color clears on Intel's Gen11 hardware. This will allow Linux users to activate the feature when Gen11 hardware launches even if Intel's own Iris Gallium3D driver hasn't debuted by then.
Intel announced the Gen11 graphics architecture for its integrated GPUs in December 2018. More details about the architecture arrived on March 21 with little fanfare; the company merely posted a document about what the next generation of its integrated GPUs would be capable of. Early benchmarks indicated that Gen11 graphics could be more powerful than AMD's Vega 10 in some games, but we haven't tested it ourselves.
We don't know when exactly Intel plans to release the first products based on the Gen11 graphics architecture (although some leaked roadmaps offer a few clues), but it will probably be at least a few months. That's likely why the company hasn't rushed to add support for fast color clears via the Iris Gallium3D driver--there probably isn't much rush to release the driver when the hardware it's meant for hasn't been announced yet.
But that didn't stop Intel from helping the folks at Mesa add support for the technology, which is said to improve performance in MSAA anti-aliasing, in version 19.1 debuting in May.
"Intel developers have (re-)enabled the Gen11 fast color clears support after working out some issues in the earlier implementation," Phoronix said in its report. "It was flipped on just in time for this week's Mesa 19.1 code branching."