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. Rosewill RS-MI-01: An Ultra Low-Cost Mini-ITX Chassis
  2. D-Link DCS-2330L HD Wireless Network Camera
  3. Gigabyte AM1M-S2H
  4. AMD's New Athlon/Semprons Give Old Phenom CPUs A Big Run For The Money
Latest Linux Articles
  1. Red Hat Enterprise Linux 7.0 RC Benchmarks
  2. AMD Catalyst 14.4 Brings Few Linux Performance Improvements
  3. The Performance Of Fedora 20 Updated
  4. Clang Fights GCC On AMD's Athlon AM1 APU With Jaguar Cores
Latest Linux News
  1. NGINX 1.6 Brings SPDY 3.1 & Other New Features
  2. Linux Foundation Announces A Core Infrastructure Initiative
  3. More Steam Linux Tests/Benchmarks Might Be Coming
  4. NVIDIA's Amazing Single-Board ARM Computer Might Be Delayed
  5. Fedora 21 To Get A Playground, New Features
  6. PC-BSD Is Developing Its Own Desktop Environment
  7. Valve Is Bringing VOGL To Windows & Working On Regression Tests
  8. Canonical Is Taking Over Linux 3.13 Kernel Maintenance
  9. Google Web Designer Is Now Natively Available On Linux
  10. Ubuntu 14.10 Is Codenamed The Utopic Unicorn
  11. Audacious 3.5 Lightweight Audio Player Released
  12. Steam Updated For Ubuntu 14.04 LTS, SteamOS
Latest Forum Discussions
  1. What Else Would You Like To See On Phoronix This Spring?
  2. HTPC-upgrade advice: AMD Richland A8-7600 or Kaveri A10-6700T ???
  3. Linux Kernel Developers Fed Up With Ridiculous Bugs In Systemd
  4. The GNOME Foundation Is Running Short On Money
  5. The Most Amazing OpenGL Tech Demo In 64kb
  6. Announcing radeontop, a tool for viewing the GPU usage
  7. New card. Open source drivers only.
  8. Script for Fan Speed Control