1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking Benchmarking Platform
Phoromatic Test Orchestration

Patches Arrive For DRM2 Render Nodes Support

Wayland

Published on 29 September 2012 01:56 AM EDT
Written by Michael Larabel in Wayland
Comment On This Article

Taking a brief break from his direct work on Wayland, Kristian Høgsberg has published his "Render Nodes" work for DRM2 following the recent DRM2 proposal.

There was a DRM2 proposal at XDC2012 earlier this month to increase the Direct Rendering Manager security.

Kristian explains in his mailing list patch series:
The core problem is that DRM security is compromised in the face of VT switching and multiple DRM masters. Any local user can access all shared buffers from within any X server on the system, even when that user doesn't have access to any of those X servers.

The fix for this is to use dmabuf/prime and fd passing for buffer sharing. That infrastructure is already in place and we need to start using that in user space. Once we're passing buffers between display servers and clients in a point-to-point fashion, we no longer need to authenticate clients. We just need to make sure they can only render and import/export buffers to fds. That's what this patch does, by creating a new type of drm device node. Accessing this node doesn't require authentication (and as such can be used without a master, ie headless), but will only expose the safe, modern (DRI2ish) rendering ioctls.

Once userspace is sharing buffers through fd passing, the legacy card0 node can be locked down by unix permissions, for example in a drm-master group, so that only setgid binaries (X, weston, other KMS apps) can access it.
The DRM render nodes patches amount to just a few dozen lines of code across three patches. With the current patches from Kristian, render nodes support is only implemented in the Intel DRM and not within Radeon, Nouveau, or other drivers.

A while back there was also other render node work being done by David Airlie.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Articles & Reviews
  1. Sub-$20 802.11n USB WiFi Adapter That's Linux Friendly
  2. The Lenovo T450s Is Working Beautifully With Linux
  3. Linux 4.0 SSD EXT4 / Btrfs / XFS / F2FS Benchmarks
  4. Linux 4.0 Hard Drive Comparison With Six File-Systems
  5. Lenovo ThinkPad T450s Broadwell Preview
  6. How Open-Source Allowed Valve To Implement VULKAN Much Faster On The Source 2 Engine
Latest Linux News
  1. AMD Releases New "AMDGPU" Linux Kernel Driver & Mesa Support
  2. A Gigabyte Sandy/Ivy Bridge Motherboard Now Handled By Coreboot
  3. Linux 3.16 Through Linux 4.0 Performance Benchmarks
  4. Intel's Windows Driver Now Supports OpenGL 4.4, Linux Driver Still With OpenGL 3.3
  5. DRM Graphics Updates Sent In For The Linux 4.1 Kernel
  6. More eBPF Improvements Heading To Linux 4.1
  7. LLDB Is Getting Into Shape For Linux 64-bit Debugging
  8. Wine-Staging 1.7.41 Works On Improved Debugging Support
  9. GNOME 3.18 Release Schedule: 23 September Release
  10. Library Operating System (LibOS) For Linux Still Being Pursued
Most Viewed News This Week
  1. Nouveau: NVIDIA's New Hardware Is "VERY Open-Source Unfriendly"
  2. Linux 4.1 Brings Many Potentially Risky x86/ASM Changes
  3. Microsoft Announces An LLVM-Based Compiler For .NET
  4. LibreOffice 4.5 Bumped To Become LibreOffice 5.0
  5. Linux Audio Is Being Further Modernized With The 4.1 Kernel
  6. KDBUS Is Taking A Lot Of Heat, Might Be Delayed From Mainline Linux Kernel
  7. VirtualBox 5.0 Beta 2 Released
  8. Mozilla Start Drafting Plans To Deprecate Insecure HTTP