With the VC4 Gallium3D driver in its current state, the X.Org Server can start-up with the generic xf86-video-modesetting DDX and experience 2D acceleration using GLAMOR, the library now part of the xorg-server accelerating 2D using OpenGL.
While X with GLAMOR is starting to work for the VC4, as Eric acknowledges, there's "a bunch of visual issues, and what you can't see is that after a few frames of those gears the hardware locked up and didn't come back. It's still major progress."
Along with the VC4 Gallium3D driver that's part of mainline Mesa is the new DRM kernel driver that Eric has been developing too for the Raspberry Pi. More details on this latest VC4 work can be found via Eric's blog.