GNOME Bugzilla – Bug 789489
Can't start up using Wayland in Ubuntu 17.10: error: linking with uncompiled shader
Last modified: 2018-10-25 21:20:54 UTC
Upgraded to the shiny new Ubuntu 17.10 today which replaced Unity by Gnome 3 and also introduced Wayland. I can't log in using Wayland, see https://bugs.launchpad.net/bugs/1727356 . The same OS installation works fine when using 'Ubuntu with Xorg'. The reason for this report is, debug logs there hint on a failure in gnome-shell: gnome-shell[5180]: Shader compilation failed:#0120:44(42): warning: `cogl_texel0' used uninitialized#0120:72(36): error: could not implicitly convert operands to arithmetic operator#0120:72(18): error: operands to arithmetic operators must be numeric gnome-shell[5180]: Failed to link GLSL program:#012error: linking with uncompiled shader gnome-shell[5180]: driver/gl/cogl-pipeline-progend-glsl.c:384: GL error (1282): Invalid operation I'm a developer, but by no means an OpenGL expert, so I googled and found this: https://www.khronos.org/opengl/wiki/Shader_Compilation Putting this together, it looks like gnome-shell tries to compile and use GLSL shaders, which are a OpenGL 4+ feature, and bails out if this doesn't work. This PC has Intel integrated graphics, supporting OpenGL 1.2.
Logs from the Launchpad bug show that the hardware is: Integrated Graphics Chipset: Intel(R) G33
Created attachment 362689 [details] Diff for removing all shader code In an attempt to narrow down the problematic area I pretty boldly commented out all code with 'shader' or 'GLSL'. Without understanding how the code works, simply by grep'ing. That's a success. Xorg sessions still work fine. For Wayland sessions, all gnome-shell messages are gone from syslog. Session initialization gets a lot farther, apparently past gnome-shell stuff. Still not a solution, of course, but now one can narrow down further by bisecting, like reducing the amount of commented out code.
If this fix works: https://gitlab.gnome.org/GNOME/mutter/commit/f7af32a3eaef then I think this bug will turn out to be moot. Maybe see this one instead: https://gitlab.gnome.org/GNOME/mutter/issues/127
Traumflug, Please try Ubuntu 18.10. If that works then I think you will find the real problem was https://gitlab.gnome.org/GNOME/mutter/issues/127
Yes, going into a Wayland session works just fine after the upgrade to 18.10 (coming with mutter 3.30.1).