For me, "apt-get remove libnvidia-gl-390" solved it. No idea how it came to be installed, but for some reason the active EGL driver was nvidia, and that interfered with the X start sequence.
For me, "apt-get remove libnvidia-gl-390" solved it. No idea how it came to be installed, but for some reason the active EGL driver was nvidia, and that interfered with the X start sequence.