So, after investigating this problem, I finally saw the cause: under X.org, the environment variable LIBGL_ALWAYS_SOFTWARE is set to 1 *always*. Without it, it uses the intel driver as usual:
$ LIBGL_ALWAYS_SOFTWARE=0 glxinfo | grep -i opengl OpenGL vendor string: Intel Open Source Technology Center OpenGL renderer string: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2) OpenGL core profile version string: 4.5 (Core Profile) Mesa 18.0.0-rc5 OpenGL core profile shading language version string: 4.50 OpenGL core profile context flags: (none) OpenGL core profile profile mask: core profile OpenGL core profile extensions: OpenGL version string: 3.0 Mesa 18.0.0-rc5 OpenGL shading language version string: 1.30 OpenGL context flags: (none) OpenGL extensions: OpenGL ES profile version string: OpenGL ES 3.2 Mesa 18.0.0-rc5 OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20 OpenGL ES profile extensions: This is probably because I have an old unity file that's running when my session starts (/etc/X11/Xsession.d/50_check_unity_support) with these contents: # This file is sourced by Xsession(5), not executed. # If the hardware does not pass unity_support_test, fall back to LLVMpipe # which does. if [ "x$DESKTOP_SESSION" = "xubuntu" ]; then /usr/lib/nux/unity_support_test || export LIBGL_ALWAYS_SOFTWARE=1 fi And given that the file /usr/lib/nux/unity_support_test doesn't exist anymore, it always exports the variable. I think that there is still a bug here, and some possible fixes: a) Remove the offending file when unity is removed b) Fix the condition to check if unity_support_test exists c) Be sure that ubuntu-bug reports the status of the flag for mesa bugs d) Make that glxinfo prominently warns that the current env forces it to run in software mode -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1755097 Title: LIBGL_ALWAYS_SOFTWARE=1 renderer used instead of Intel on Xorg sessions because of unity leftover file /etc/X11/Xsession.d/50_check_unity_support To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1755097/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp