Intel Aiming For Their Gallium3D Driver To Be Viable By Mesa 19.2, Default By EOY 2019
Following questions from our forum goers, there's now an overview of the current state of Intel's new "Iris" Gallium3D driver and its road-map for the remainder of the year in being the company's next-gen OpenGL driver that should be in especially good shape by the time Icelake "Gen 11" hardware arrives.
The Intel Gallium3D driver was merged back in February and will be found in next month's Mesa 19.1 release for the first time. With our testing of this "Iris" driver in Mesa 19.1 Git, the performance has become quite comparable recently to the existing i965 driver and in fairly good shape (and the performance is only getting better). With Mesa 19.1 it won't be used though unless going for the environment variable override with the mature Intel classic driver being the default. But by the end of 2019, this Gallium3D driver might be the default for supported hardware -- this driver supports Broadwell "Gen 8" graphics and newer while older generations of Intel graphics will continue to see support via the i965 classic driver.
Kenneth Graunke of the Intel Open-Source Technology Center who started this driver effort more than a year ago has put out a milestone update for those wondering about the exact peculiarities of this new driver. Exciting beyond the goal to have it be the default driver by the end of 2019 is for it to be a "viable replacement" to i965 by the Mesa 19.2 release in August.
Known issues with this new driver include H.264 video playback failing, flickering issues with some games, and various other OpenGL features not yet in place or potentially causing incorrect rendering. As for Piglit and other OpenGL test cases, Iris is currently seeing around a 95% pass rate.
As for the performance, the Intel developers have found the CPU overhead to be dramatically less and many programs running 10~15% faster.
The timing for the default change in the OpenGL driver is great if that is successful for Mesa 19.3 considering we should hopefully be seeing the initial Icelake processors with Gen11 graphics by year's end. And most excitingly, it looks like the initial Intel Xe Graphics discrete hardware is still on track for a 2020 debut that for the Linux OpenGL driver support will likely exclusively target Iris over their classic Mesa driver.
Those wanting to know more about the current Intel Gallium3D driver state can find the current status via Ken's Gitlab milestone.