(In reply to comment #74)
> Ok, but how do I make sure that si_get_backend_mask() gets information from
> the kernel ?

By tracing its execution flow, either in gdb or by adding debugging printfs.

> > Also, might be worth testing with R600_DEBUG=nodma for now, to prevent the
> > userspace code from using the asynchronous DMA engine.
> Will do that.

Actually, that was a red herring, sorry; there's no asynchronous DMA support
yet for CIK.

> LLVM triggered Diagnostic Handler: unsupported call to function
> llvm.AMDGPU.rsq. in main

You need to update your LLVM SVN/Git snapshot.