Older Intel Graphics With Crocus Enjoy EXT_gpu_shader4, GLAMOR 2D Improvements

Mesa's independent Crocus Gallium3D driver providing a modern OpenGL driver alternative for Haswell and older graphics hardware continues seeing improvements following its recent mainlining.

Crocus is already in quite good shape for i965 through Haswell Gen7 graphics though some generations are better off than others. With recent Mesa 21.2 code from the past week, Gen4/Gen5 is seeing better support for workloads at least relying on EXT_gpu_shader4 support. EXT_gpu_shader4 was originally developed by NVIDIA during the GeForce 8 days to extend GLSL for providing new texture lookup functions, full signed integer / unsigned integer support for GLSL, and other features.

Intel hardware from more than one decade ago continues seeing open-source Linux driver improvements.

This upstreaming follows requests from users over wanting said functionality on older Intel graphics. In particular, Libreboot users still running GM45 hardware with GMA 4500 graphics due to its open nature. Getting the Shader4 extension running at least allows more OpenGL software to run on these vintage integrated graphics albeit not necessarily the fastest.

Besides David Airlie of Red Hat adding the EXT_gpu_shader4 support to Mesa, he also merged support for EXT_gpu_shader4 within the X.Org Server's GLAMOR code. This allows using a number of GLSL 1.30 paths on GPUs that have this extension but don't have GLSL 1.30 in full. This should yield greater support/performance for Intel Gen4/Gen5 graphics with this generic 2D acceleration via OpenGL for the X.Org Server.