For this initial testing I was using the Linux 4.11 kernel and Mesa 17.1-devel for providing a bleeding-edge open-source driver experience. As mentioned already, in a follow-up article I will post AMDGPU-PRO results as well as some DRM-Next runs and soon switch over to using Mesa 17.2-dev Git now that 17.1 has been branched.
When booting up the system, I was pleased to see the Radeon RX 580 mode-set right away to 4K and graphics acceleration was working! This Radeon RX 580 graphics card is currently identified on Linux as a "Radeon RX 470/480."
The AMDGPU DRM driver successfully loaded. Note that right away is a warning regarding PowerPlay, but everything seems to have worked.
The RadeonSI driver was showing off OpenGL 4.5 on the graphics card just identified as a "POLARIS10."
The open-source RADV driver was also working fine with this revised Polaris graphics card. This MSI Radeon RX 580 8GB card had a PCI ID of 0x67df. This open-source driver support for these Radeon RX 500 cards has been around for a while. Last March in AMD Publishes Initial Open-Source Driver Code For Next-Gen Polaris is when the initial patches were posted for the 0x67DF card and thus is already in kernel revisions around ~4.7.
The major support shortcoming right now for the Radeon RX 580 on the mainline Linux driver is no support for FreeSync nor HDMI/DP audio nor any other advanced display features implemented only on the DC (formerly DAL) display stack. The DC code isn't being merged until at least Linux 4.13 so either you'll need to build your own out-of-tree kernel code or use the AMDGPU-PRO driver if you rely upon HDMI/DP audio, FreeSync, etc. But with all normal support in place, let's see how it performs.