The Huge DRM Driver Update Submitted For Linux 4.12: Vega, Atomic & Co

David Airlie has submitted the Direct Rendering Manager (DRM) feature changes for the Linux 4.12 kernel. The DRM changes this time around are particularly massive, driven by the addition of the initial Radeon RX Vega support.

Previously we've already reported on the exciting DRM changes of Linux 4.12, but now that the pull request is out there, for those that missed our earlier coverage here we roll again:

The most notable Linux 4.12 DRM addition is the initial Radeon Vega support. Vega should be launching later in May. This initial Vega support is over three hundred thousand lines of code due to all of the register definitions added for Vega. But before getting too excited for Vega in Linux 4.12, be aware there is no display support. DC/DAL isn't landing for Linux 4.12 and until that lands, there won't be any Vega display capabilities in the mainline kernel. So if you want to attach a monitor, you'll need to use an out-of-tree kernel module or a future AMDGPU-PRO release. The Vega use-cases for now without display support is basically for compute.

The AMDGPU changes also have multi-level page table support, GPU sensor support for user-space, PRT (partial resident textures) for sparse buffers, SR-IOV improvements, non-contiguous vRAM CPU mapping, and more.

Over on the Intel side they have now turned on atomic mode-setting by default for Intel Ironlake hardware and newer. Great to see atomic-by-default finally for them! Intel also has more Geminilake enablement, GPU reset improvements, display improvements, GVT Kabylake support for graphics virtualization, and more.

Exciting for Nouveau in Linux 4.12 is acceleration for GeForce GTX 1000 series hardware as shown in those early Pascal benchmarks. But this Pascal 3D support is slow as there isn't yet any re-clocking support for Pascal (or Maxwell). There is also GP10B support for Nouveau in Linux 4.12, the GPU found in the Tegra Parker / TX2 SoC. The new Pascal support in Linux 4.12 does require NVIDIA-signed firmware image binaries.

Core DRM in Linux 4.12 is also now aware of external GPUs via Thunderbolt. The VMware VMWgfx virtual driver also has atomic mode-setting support. Exciting for Raspberry Pi users is the VC4 driver now has HDMI audio support.

Largely driven by the Vega support, the pull request is huge at 457,052 lines of new code and 27,145 deletions across 1,070 files. The complete list of DRM driver changes for Linux 4.12 via this pull request.