Mesa Adds Option For Changing Intel's OpenGL Driver Default

While originally Intel planned to transition their OpenGL driver default to the modern "Iris" Gallium3D driver rather than the longstanding "i965" DRI driver for Mesa 19.3, that was pushed back to Mesa 20.0 for introduction in Q1'2020. In aiming to make that revised milestone a reality, a new option has been added to Mesa 20.0 with the Meson build system for being able to indicate the Intel OpenGL driver preference.

The plan is for Mesa 20.0 to default to their new Gallium3D driver with Broadwell "Gen8" graphics and newer, including Icelake "Gen11". It's with Tiger Lake "Gen12" graphics where there is only support being implemented anyhow on this Gallium3D driver and not the older i965 OpenGL driver. As it stands right now when building Mesa, the i965 driver is used by default and then an environment variable allows overriding the driver to load in order to use Iris Gallium3D.

Intel's Kenneth Graunke added a new Meson build option today of "prefer_iris". When set to true, the prefer_iris caters the build to preferring Iris Gallium3D over i965 and thus used by default with Gen8 hardware and newer.

A separate patch expected for Mesa 20.0 still is what will then default prefer_iris to true in order to use this new Intel Gallium3D driver by default on supported graphics hardware. Even on Mesa 19.3, the Intel Gallium3D driver is in really great shape and generally delivering much better performance than i965, so I would encourage Broadwell users and newer to give this new open-source driver a whirl. Mesa 20.0 meanwhile should be out as stable around the end of February.