DRM Driver Changes Sent In For Linux 4.9, Sadly No Changes For Nouveau

David Airlie a short time ago submitted the Linux 4.9 DRM subsystem update, including the much sought after open-source Direct Rendering Manager driver improvements. There's a lot of good stuff in here, but sadly the Nouveau changes look like they're going to have to wait until Linux 4.10.

Highlights for the DRM updates in Linux 4.9 include:

AMDGPU gets Virtual Display Support, improved GPU reset support, PowerPlay for Iceland GPUs, pre-initialized VRAM buffer support, a GTT code rework, UVD/VEC power-gating for Carrizo and Stoney hardware, and a fun experimental feature... Experimental Southern Islands support! But like the GCN 1.0 support, this GCN 1.0 AMDGPU support needs to be enabled at compile-time via a new Kconfig switch. Not for a while will AMDGPU support GCN 1.0/1.1 GPUs by default rather than the mature Radeon DRM driver.

See my early GCN 1.0/1.1 AMDGPU benchmarks from the DRM-Next code for those with Radeon HD 7000 series and similar hardware that may want to try running this experimental functionality.

The Intel DRM driver has its usual wide assortment of fixes and improvements including DMA-BUF implicit fencing, memory management improvements, frame-buffer compression fixes, vGPU improvements, better DisplayPort dongle support, and more.

The Raspberry Pi VC4 DRM driver meanwhile has CPU/memory overhead reduction during 3D rendering and other improvements.

When it comes to the smaller DRM drivers, the Mediatek DRM code has AAL + GAMMA engine and temporal dithering support, iMX has color space conversion support, Rockchip has Panel Self Refresh (PSR) support as well as RK339 VOP/CRTC support, Freedreno MSM has explicit fence FD support, Etnaviv has GC3000 support, and the Sunxi DRM driver has Allwinner A33 support.

Sadly, there are no Nouveau DRM driver changes included with this Linux 4.9 pull request... This is especially sad as the initial Nouveau "Boost" support was expected to land. Of no open-source NVIDIA driver changes, David Airlie commented, "there is no nouveau work in this tree, as Ben didn't get a pull request in, and he was fighting moving to atomic and adding mst support, so maybe best it waits for a cycle." Thus due to atomic mode-setting work and DP Multi-Stream Transport (MST) work, it doesn't look like any Nouveau changes will come for Linux 4.9 but rather all the work be postponed to Linux 4.10.

The complete pull request with all the DRM driver changes can be found via this kernel mailing list message.