(In reply to comment #17)
> I can at least confirm that the lock-ups also happen on a CEDAR (HD 5400)
> with the 3.9.0 kernel and latest drm/llvm/mesa master.  This machine at
> least doesn't hard lock (GPU resets after 10 seconds...), so I'll attach the
> results of:
> 
> R600_DEBUG=trace_cs,nodma bfgminer -v1

One thing you may want to check is that Mesa is picking up the correct LLVM
shared object.  The LLVM version was just bumped and the current shared object
is now called libLLVM-3.4svn.so.  I just ran into this problem myself.