Among the highlights of the Mesa 17.1.0 Release Candidate 4 milestone, we can mention SCons support for LLVM 4.0, Polaris 12 support for the Radeon RADV Vulkan driver, along with a workaround for a tess+GS hang, also for Polaris 12, and use of helper function for modifier – tiling on the Intel i965 driver. Polaris 12 support was also improved for the RadeonSI driver, specifically for the AMD Radeon RX 550 graphics card, and Mesa 17.1 RC4 adds L8A8_UNORM texture format support for the Etnaviv open source user-space driver for the Vivante GCxxx series of embedded GPUs.