I'm certain that none of those are the cause - it's entirely a driver problem. Trouble is I can't get the right driver to work with my newer kernel. It's a linux specific problem I suppose. I'm really wanting it to work on this rig because I use it for oh so many things, but linux GPU support is just horrid.
That not a linux driver error only, that's happen also on windows.
Look like amd made change in their driver and amd_bytealign function didn't work as expected.
If you want to use 13.4 driver, just modify the opencl kernel by removing the BFI_INT optimization which cause the problem on 13.4
Try running Cgminer in benchmark mode, eliminate network from variables.
--benchmark Run cgminer in benchmark mode - produces no shares
--debug|-D Enable debug output
So it's " cgminer --benchmark --debug "
Benchmark mode results in invalid nonce.