Intel "Crocus" Driver For Old iGPUs Bumps OpenGL Compatibility Profile Support

The Intel Crocus Mesa driver providing open-source Gallium3D support for older i965 through Haswell era graphics hardware now offers much better OpenGL compatibility profile support.

For an OpenGL core context the Crocus Gallium3D driver has long exposed OpenGL 4.6 support or OpenGL 3.3 on prior generations of Intel graphics due to hardware restrictions. Meanwhile when creating an OpenGL compatibility profile context it has been limited to GLSL 140 / OpenGL 3.1.

Haswell graphics and back to i965 enjoy great open-source Gallium3D-based OpenGL support with Crocus.

That lower OpenGL compatibility profile restriction though with time has been overkill and is now being raised. This merge request that's been open for a half-year now allows Crocus to advertise the same OpenGL compatibility profile versions as a core context -- OpenGL 4.6 for Haswell/Gen7.5 graphics and newer or OpenGL 3.3 for prior generations.

The higher compatibility context version does yield three new Piglit OpenGL test case failures, but overall not bad considering the age of the hardware and Crocus being started in the past two years independent of Intel as a replacement to the i965 classic Mesa driver.

The change to raise the OpenGL compatibility context version is in for next quarter's Mesa 22.1. The OpenGL compatibility profile allows for making use of deprecated/removed GL functionality within newer versions of the OpenGL spec compared to that of the core context.