DRM Changes Pooling For Linux 3.5 Kernel

There's already a number of changes building up when it comes to the Direct Rendering Manager (DRM) sub-system for merging into the Linux 3.5 kernel.

On Friday there was a "state of drm next" e-mail sent by David Airlie, the Red Hat developer that's also the Linux kernel's DRM sub-system maintainer.

Building up so far has been a tentative "-next" tree from Intel with various work but nothing too interesting yet and on the Radeon side there's copy optimization, a PCI bus master race fix, and two AGP patches. That's been it for what's happened to the drivers, but the Nouveau pull hasn't went in nor are the Radeon/Intel "-next" pulls over.

Expected for merging into the Linux 3.5 kernel will be the Valley View Atom SoC (VLV) and Haswell (HSW) hardware enablement code. However, if you're hoping Intel will squeeze out more Sandy/Ivy Bridge performance improvements on the Intel side in the near future, it doesn't look that way. Daniel Vetter wrote in an email to me earlier this week when we were discussing my Intel Ivy Bridge Linux benchmarking, "For the next month I don't see anything big wrt performance, most of the stuff currently being worked on is new platform enabling for vlv&hsw and code rework to make that happen."

Hopefully on the Nouveau side they will have more to merge when it comes to re-clocking support, but at the moment it doesn't look too likely. It would also be nice for them to free-up the need for the FUC microcode for the GeForce 600 "Kepler" hardware so that loading the NVIDIA binary driver and extracting the firmware doesn't need to happen, but that might not happen until Linux 3.6 or later.

On the Radeon side, performance improvements are still needed but AMD developers at the moment are still busy tackling the new "RadeonSI" Gallium3D driver. Maybe they will finally get PCI Express 2.0 support enabled by default for Linux 3.5? Probably not.

Getting back on track with David's message, yesterday into his drm-core-next Git repository he landed a frame-buffer creation sanity check patch series, CEA/EDID patches, and DMT mode-adding patches. Into the drm-next tree is also work by Matthew Garret on handling multi GPUs with EFI interactions.

Outside of what's been pulled or talked about for being on the table for Linux 3.5, there's also some related work going on still with DMA-BUF. One of the recent much-discussed patch-sets concerning DMA-BUF has been integrating import/export support for it with the V4L2 stack, with the set of 13 patches already having gone through five revisions (the latest).

The Linux 3.5 kernel is a ways out with the Linux 3.4 kernel only at its -rc3 stage (but nearing -rc4) at the moment. In the meantime you can read about the DRM graphics driver changes for Linux 3.4.