The Main DRM Pull Request For The Linux 2.6.37 Kernel

David Airlie has just called upon Linus Torvalds to pull in his DRM kernel tree for the Linux 2.6.37 kernel merge window. We have talked about many of these features before that are now entering the mainline Linux kernel code-base as new capabilities of the open-source Linux graphics stack, but here's the list of what made the cut for Linux 2.6.37 and details on some of the features we have yet to discuss.

When it comes to the common DRM core area, the Linux 2.6.37 kernel is set to add KDB LUT support that will allow for better kernel debugging for those using a KMS driver, code-cleanups, and EDID enhancements for reading audio capabilities. The general TTM (Translation Table Maps) memory manager in the kernel now has an optimized eviction process for eliminating unnecessary object movements and support for an alternate memory manager to be plugged in underneath TTM. This TTM support for allowing the DRM driver to plug-in an alternate memory manager is now used by the VMware's DRM driver for their virtualization platforms with the Linux 2.6.37 kernel. This alternate memory manager for TTM support was originally patched by the Nouveau developers as it's needed for the GeForce 8 and newer, as these NVIDIA GPUs are reordering physical video memory for some memory types.

When it comes to Nouveau DRM in the Linux 2.6.37 kernel, this community-written open-source NVIDIA driver now will support power management though it's still being tuned (thanks in part to you, our readers). The Nouveau 2.6.37 DRM also has hardware inter-channel sync support, better handling of GPU errors and non-mappable video memory, tiling corruption fixes, and NVAF support.

The Radeon DRM in the Linux 2.6.37 kernel is set to introduce new fences on R600 ASICs and newer, spread spectrum improvements on R500 and newer, Radeon HD 5000 series blit support, PLL fixes, and a number of tiling fixes. The Radeon DRM in the 2.6.37 kernel though will not carry page-flipping support or any form of Radeon HD 6000 Linux support. It also looks like the precise vblank timestamps have not been part of this pull request.

With Intel's DRM for this kernel development cycle they have a rework of their AGP/DRM driver interfaces, support for using the whole GTT range instead of just using the CPU mappable region, Embedded DisplayPort (eDP) fixes, unload fixes, DisplayPort audio, and output bug-fixes.

A new DRM driver to the Linux 2.6.37 kernel is the new Intel Poulsbo driver, but before you get too excited, this is just the "dumb" driver being used for providing back-light support on the sysfs interface. While falling within the Linux graphics realm but not within the DRM stack, the Linux 2.6.37 kernel also has DisplayLink driver improvements for those using these USB displays.

As mentioned last week, there still is no VIA DRM support. Per their Linux TODO list, we should be seeing GEM/TTM memory management and kernel mode-setting support for their Chrome IGPs, but we haven't seen anything yet. VIA hoped to have a Gallium3D driver in the works this year too. With no VIA code for the Linux 2.6.37 kernel, we won't see anything until at least year. That is if we see anything at all, there hasn't been any VIA communications in months, the OpenChrome mailing list has been silent in months, and Bruce Chang who had been heading these VIA Linux efforts no longer seems to be responding to our email inquiries.

David's pull request message for Linux 2.6.37 can be read on dri-devel.