RadeonSI Driver Adding Displayable DCC For Raven Ridge

Delta Color Compression (DCC) support for scan-out surfaces will soon be supported by AMD Raven Ridge hardware in conjunction with the latest AMDGPU Linux kernel code and the RadeonSI OpenGL driver.

The open-source AMD Linux driver stack hasn't supported Delta Color Compression for scan-out surfaces on Raven Ridge, but this feature is being addressed by AMD's Marek Olšák for this feature to help conserve memory bandwidth and in turn enhance performance. Up to now the DCC support hasn't supported the surfaces being scanned out to the display.

Marek posted a set of 5 patches for allowing the "displayable DCC" for Raven Ridge APUs. This requires the very newest AMDGPU kernel driver code for what will be in Linux 5.1 as well as a new xf86-video-amdgpu DDX driver patch.

No word/benchmarks on any end-user visible performance changes as a result of this Raven scanout DCC were provided in the initial patch comments. My Ryzen 5 2400G system is still finicky under Linux even with the latest kernel and BIOS when last trying in February, but will at least look forward to testing out this capability with the Ryzen 3 2200G once it lands in Mesa 19.1-devel.

The RadeonSI patches also enable this displayable DCC capability for the yet-to-launch Raven 2 APUs. Mesa 19.1 will be out as stable in May, roughly around the time as well of Linux 5.1 that is bringing the necessary kernel bits.