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. Intel Xeon E5-1680 v3 & E5-2687W v3 Compared To The Core i7 5960X On Linux
  2. Intel 120GB 530 Series SSD Linux Performance
  3. Btrfs/EXT4/XFS/F2FS RAID 0/1/5/6/10 Linux Benchmarks On Four SSDs
  4. AMD's Windows Catalyst Driver Remains Largely Faster Than Linux Drivers
Latest Linux Articles
  1. NVIDIA vs. Nouveau Drivers With Linux 3.18 + Mesa 10.4-devel
  2. Is The Open-Source NVIDIA Driver Fast Enough For Steam On Linux Gaming?
  3. Linux 3.18 File-System Performance Minimally Changed But Possible Regressions
  4. AMD Radeon Gallium3D Is Catching Up & Sometimes Beating Catalyst On Linux
Latest Linux News
  1. Gngr: A New Web Browser Focused On Privacy
  2. Linux 3.18 Kernel: Not Much Change With Intel Haswell Performance
  3. More File-System Tests Of The Linux 3.18 Kernel
  4. Using NVIDIA's NVENC On Linux With FFmpeg
  5. There's Talk Again About An "Open To The Core" Ubuntu Laptop
  6. PowerVR SGX Driver Code Gets Leaked
  7. V2 Of KDBUS Published For Linux Kernel Review
  8. VirtualBox 4.3.20 Arrives, Still No Sign Of VirtualBox 4.4
  9. Scientific Linux 6.6 vs. Scientific Linux 7.0 Benchmarks
  10. Qualcomm Looks To Get Into The ARM Server Business
Latest Forum Discussions
  1. Debian Developer Resigns From The Systemd Maintainership Team
  2. Roadmap to Catalyst 14.10 ?
  3. Updated and Optimized Ubuntu Free Graphics Drivers
  4. Cant get working Kaveri APU - A10-7850k
  5. Script for Fan Speed Control
  6. Debian Init System Coupling Vote Results
  7. The Slides Announcing The New "AMDGPU" Kernel Driver
  8. Ubuntu Developers Still Thinking What To Do About Adobe Flash Support