Comment 43 for bug 1966418

(In reply to Jeremy Bicha from comment #4)
> The first 2 did not work for me but the 3rd did.
>
> iris
> ----
> $ MESA_LOADER_DRIVER_OVERRIDE=iris yelp
> EGLDisplay Initialization failed: EGL_NOT_INITIALIZED
> Cannot create EGL context: invalid display (last error: EGL_SUCCESS)
> Unsupported modifier, resource creation failed.
> XXX: resource creation failed
>
> zink
> ----
> $ MESA_LOADER_DRIVER_OVERRIDE=zink yelp
> MESA-INTEL: warning: Performance support disabled, consider sysctl
> dev.i915.perf_stream_paranoid=0
>
> MESA-INTEL: warning: Performance support disabled, consider sysctl
> dev.i915.perf_stream_paranoid=0
>
> EGLDisplay Initialization failed: EGL_NOT_INITIALIZED
> Cannot create EGL context: invalid display (last error: EGL_SUCCESS)

Zink will use internally lower-level parts from the Iris driver to access
the hardware, so at least this indicates that the issue is *below* the
OpenGL/GLES implementation. Could be EGL or hardware access, I suppose.

> i965
> ----
> $ MESA_LOADER_DRIVER_OVERRIDE=i965 yelp
> libEGL warning: MESA-LOADER: failed to open i965: /usr/lib/dri/i965_dri.so:
> cannot open shared object file: No such file or directory (search paths
> /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
>
> WaylandCompositor requires eglBindWaylandDisplayWL,
> eglUnbindWaylandDisplayWL and eglQueryWaylandBuffer.
> Nested Wayland compositor could not initialize EGL
> libEGL warning: MESA-LOADER: failed to open i965: /usr/lib/dri/i965_dri.so:
> cannot open shared object file: No such file or directory (search paths
> /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)

When a driver that was set explicitly like this fails to load, Mesa falls
back to using software rendering. This means you ended up here using the
swrast/llvmpipe driver, most likely (you can load “webkit://gpu” in the
Minibrowser or Epiphany to check this). This means that WebKit is most
likely using the GLX/EGL/OpenGL/GLES APIs correctly and the issue lies
somewhere in the Intel driver.

But the version of Mesa I am using here is the same as you and it works.
My suspicion is that one of the following is happening:

 * Patches applied by Debian/Ubuntu on top of Mesa are breaking the Intel
   driver. Here I am using Arch Linux, which does not apply any patches.
 * The Intel driver is being miscompiled somehow by the compiler toolchain
   shipped by Ubuntu. In case it helps, here Arch stable has GCC 11.2.0 as
   the default system compiler, so that's what gets used to build packages.
 * The bug could be related to your particular GPU model (and the
   corresponding code inside Mesa for it).

I hope this helps :)