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.org

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 Linux Hardware Reviews
  1. Trying The Configurable 45 Watt TDP With AMD's A10-7800 / A6-7400K
  2. Sumo's Omni Gets Reloaded
  3. AMD A10-7800 & A6-7400K APUs Run Great On Linux
  4. Radeon Gallium3D Is Running Increasingly Well Against AMD's Catalyst Driver
Latest Linux Articles
  1. Intel's Latest Linux Graphics Code Competes Against OS X 10.9
  2. Intel Sandy Bridge Gets A Surprise Boost From Linux 3.17
  3. Open-Source Radeon Graphics Have Some Improvements On Linux 3.17
  4. CPUFreq Scaling Tests With AMD's Kaveri On Linux 3.16
Latest Linux News
  1. A New First-Person Mystery Game Might Be Coming To Linux
  2. Patch By Patch, LLVM Clang Gets Better At Building The Linux Kernel
  3. VC4 Gallium3D Driver Now Handles X With GLAMOR
  4. Opera 25 Development Release For Linux
  5. Steam Now Supports VA-API For In-Home Game Streaming
  6. GNOME 3.14 Beta Released
  7. Mesa 10.3 Branched & RC1 Released, Mesa 10.4 On Master
  8. Intel Sandy Bridge Gains On Linux 3.17 Extend Beyond Graphics
  9. LinuxCon: What's Going On With Fedora.Next
  10. Canonical Joined The Khronos Group To Help Mir/Wayland Drivers
Latest Forum Discussions
  1. Btrfs Gets Talked Up, Googler Encourages You To Try Btrfs
  2. Systemd 216 Piles On More Features, Aims For New User-Space VT
  3. American Citizens running AMOK for food stamps
  4. What Linux Distribution Should Be Benchmarked The Most?
  5. OSS radeon driver for A10-7850K (Kaveri)
  6. Company I work for is looking to contribute to Open Source projects... but wrongly?
  7. Microsoft vs. Campaign
  8. Updated and Optimized Ubuntu Free Graphics Drivers