Solved "eglCreatePbufferSurface failed with error "

[173210]

Hi. I'm trying to get Qt WebEngine work with eglfs_kms. However, it emits the
following error:

[0101/000155:ERROR:gl_surface_qt.cpp(419)] eglCreatePbufferSurface failed with error 
[0101/000155:ERROR:command_buffer_proxy_impl.cc(182)] Failed to initialize command buffer service.
[0101/000155:ERROR:webgraphicscontext3d_command_buffer_impl.cc(210)] CommandBufferProxy::Initialize failed.
[0101/000155:ERROR:webgraphicscontext3d_command_buffer_impl.cc(229)] Failed to initialize command buffer.

gl_surface_qt.cpp(419) is the following line:

        LOG(ERROR) << "eglCreatePbufferSurface failed with error ", GetLastEGLErrorString();

The log doesn't include a EGL error string, so I think it's failing to call
EGL functions. Any idea to fix the issue?

[173210]

Solved: the cause was the stub in mesa3d drm backend. It's solved by altering the backend.