Comment 17 for bug 1691991

Ok, so I think part of the problem is that the kernel hibmc driver needs to use a set_busid function from the drm core. I've simulated this change in the debugger, and it seems to at least prevent the crash. (It doesn't seem to be enough for the server to work, still working on that.)

Here's a patch - we can discuss the best way to build and install it.