While we have seen a number of ARM vendors in recent years open-source and mainline DRM/KMS drivers in the Linux kernel for supporting their display blocks on modern SoCs, there has been little activity in the open-source 3D space still for ARM SoCs.
Broadcom's VC4 driver while it hasn't replaced the binary driver in all cases yet is official and continues gaining ground with a fully-open DRM/KMS driver and VC4 Gallium3D driver. That driver written by Eric Anholt (formerly of Intel's Linux graphics team) is about the lone official open-source ARM 3D driver to talk about on Linux, unless you count the efforts NVIDIA has provided to Nouveau in the Tegra space.
- Linux 4.12 Release – Main Changes, ARM & MIPS Architectures
- NVIDIA Tegra186/Parker/TX2 Support For Linux 4.12
- Linux Kernel 3.18.51 Released with MIPS, ARM, and CIFS Changes, Updated Drivers
- New ARM Support Going Into The Linux 4.12 Kernel
- The anatomy of a powerful desktop with an ARM chip
- Linux, not Microsoft, the real winner of Windows Server on ARM