Previously I talked about some of the DRM changes for Linux 3.1. What is found in David's tree for the Linux 3.1 merge window is nearly the same. The open-source graphics driver changes queued up for the Linux 3.1 kernel aren't nearly as exciting as what has been merged during some of the past kernel development cycles. There isn't any major new hardware support, no ground-breaking features, or other really fundamental changes, but just some modest updates.
The biggest change, in my opinion, for the Linux 3.1 kernel DRM is that the Nouveau driver is now capable of generating its own FUC microcode. This is the microcode that is needed for accelerated support with NVIDIA GeForce 400/500 "Fermi" graphics processors. Nouveau has supported kernel mode-setting on these latest NVIDIA GPUs for several kernel releases, but there is no 2D/3D/X-Video acceleration without the "FUC" support. Previously, interested users would need to first load the NVIDIA binary driver and initialize the graphics processor so they could extract this microcode and then load it with Nouveau. With Linux 3.1+, the Nouveau driver is now able to come up with its own microcode, similar to how the "ctx_voodoo" was self-generating for previous hardware generations.
A while ago I ran some Nouveau Fermi benchmarks and on the GeForce GTX 460. After pulling in the latest Linux 3.1 kernel development code and Mesa 7.12-devel, some new open-source Fermi GeForce 400/500 benchmarks will be run shortly.
Also improving Nouveau in the Linux 3.1 kernel is per-client GPU address spaces for NV50 hardware and later.
The Intel driver in the Linux 3.1 kernel has frame-buffer compression clean-ups, high color support, ring frequency scaling, shared LLC support, and hang-check module disabling.
The Radeon driver meanwhile has initial compute shader support for the AMD Radeon HD 5000 "Evergreen" series, KMS page-flipping changes, and PowerPC / big Engian fixes.
Core DRM this time around just has miscellaneous changes, but nothing too exciting.
Still missing, of course, is any VIA kernel mode-setting support.
While not part of this pull request, the Intel GMA500 driver has improvements (a.k.a. "Poulsbo") has improvements too for Linux 3.1, including Intel Cedar Trail support.
David's 3.1 DRM feature pull request can be found on the mailing list.