I should set mesa version to smooth play in alien isolation (
https://bugs.freedesktop.org/show_bug.cgi?id=93144#c35 ). I set
"MESA_GL_VERSION_OVERRIDE=4.3 MESA_GLSL_VERSION_OVERRIDE=430". Appications and
games start carsh in gl initialization. Some examples: steam, 0ad. glxgear
shows black screen.

I use software from oibaf ppa:

Extended renderer info (GLX_MESA_query_renderer):
    Vendor: X.Org (0x1002)
    Device: AMD CAPE VERDE (DRM 2.43.0 / 4.4.0-41-generic, LLVM 3.9.0) (0x683d)
    Version: 12.1.0
    Accelerated: yes
    Video memory: 1024MB
    Unified memory: no
    Preferred profile: core (0x1)
    Max core profile version: 4.3
    Max compat profile version: 4.3
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.0

MESA_DEBUG=1 prints

Mesa: User error: GL_INVALID_ENUM in glGetString(GL_EXTENSIONS)

I'm curious why mesa does not set 4.3 already. According mesamatrix (by
features.txt) there are all extensions implemented for radeonsi.