Radeon Graphics Yield Mixed Results With Linux 3.17 Kernel

With this testing of the Linux 3.17 Git kernel just ahead of the 3.17-rc2 release, there were some performance improvements to find with the newer AMD GCN graphics cards (Radeon HD 7000 series and newer) while the testing of the HD 5000/6000 series was much more flat. The HD 5770 and HD 6950 saw little change in the testing but the HD 6870 was the unfortunate outlier with its performance having been consistently slower when using Linux 3.17 over 3.16, which is unfortunate since in general the HD 6870 is one of the best supported (and fastest) AMD GPUs by the open-source driver stack in its current form. Hopefully this and any other regressions will be found and addressed ahead of the official Linux 3.17 kernel that's still several weeks away.