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

DisplayLink Continues To Progress On Linux, But No 3D

Hardware

Published on 02 June 2011 05:51 PM EDT
Written by Michael Larabel in Hardware
Comment On This Article

It was back in May of 2009 that DisplayLink began providing open-source Linux support for their USB-interfaced graphics processors in the form of documentation and code. Shortly thereafter, frame-buffer and X.Org drivers for DisplayLink USB hardware arrived and it quickly matured. By early 2010 it was possible to produce interesting results with these USB graphics adapters doing things like driving nine monitors over USB from a single computer.

A number of features have been added in succeeding kernel releases over the past two years. Most recently, during the Linux 2.6.39 kernel development cycle, DRM support for USB devices was added making it now possible to write a Direct Rendering Manager driver for DisplayLink hardware and to hook into kernel mode-setting. The code for a DRM/KMS DisplayLink driver is not yet written, but will most likely appear at some point in the future.

One limitation of the DisplayLink Linux support that still remains, however, is the lack of 3D support. These low-power USB graphics adapters don't have a 3D engine. Under Windows, 3D on DisplayLink hardware is achieved by using the primary GPU on the system and then simply sending it out to the DisplayLink GPU so that it can be painted to that scan-out buffer. Something similar would need to be implemented under Linux so that there could be 3D support and even a composited desktop, but right now the infrastructure is lacking. This was a question recently asked on the DRI development mailing list.

This lack of infrastructure falls into the same boat of the Linux multi-GPU rendering being way behind, no AMD CrossFire / NVIDIA Scalable Link Interface support, NVIDIA Optimus for some hardware where only one GPU is connected to the output, and other technologies like LucidLogix Virtu.

Kernel changes and to the X.Org stack would be needed for this multi-GPU rendering to all play nicely. David Airlie previously experimented with a project he calls PRIME rendering for using one GPU to render and then displaying the contents on a display connected to another GPU, but it was just a proof of concept and is not being worked on at this point. As long as the graphics processor employed GEM memory management, it in theory could work with any graphics driver/GPU. Getting this work upstream is a huge feat and requires major re-architecting of the X Server and Linux drivers. With the Wayland Display Server, this will hopefully be much smoother.

Sadly, hitting these features under Linux will not be a short-term goal.

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. A Walkthrough Of The New 32 System Open-Source Linux Benchmarking Test Farm
  2. Habey MITX-6771: Mini-ITX Board With Quad-Core J1900 Bay Trail
  3. OCZ Vector 150 SSD On Linux
  4. Noctua i4 CPU Cooler: Great For Cooling High-End LGA-2011v3 CPUs
Latest Linux Articles
  1. 17-Way Linux Graphics Card Comparison With Civilization Beyond Earth
  2. AMD Kaveri: Open-Source Radeon Gallium3D vs. Catalyst 14.12 Omega Driver
  3. 12-Way AMD Catalyst 14.12 vs. NVIDIA 346 Series Linux GPU Comparison
  4. AMD Catalyst 14.12 Omega Driver Brings Mixed Results For Linux Users
Latest Linux News
  1. Intel 2.99.917 X.Org Driver Released, 3.0 Release Finally Near
  2. Server-Side XCB Is Being Discussed For The X.Org Server
  3. Adreno A4xx Rendering With Freedreno Takes Shape
  4. Linux 3.19-rc1 Kernel Released Ahead Of Schedule
  5. Civilization: Beyond Earth Linux GPU/Driver Benchmarks
  6. X.Org Server 1.16.3 Released To Fix Security Issues
  7. Linux 3.19 Merge Window Closes Ahead Of Schedule
  8. MIPS R6 Architecture Now Supported By GCC
  9. LowRISC To Feature Tagged Memory & Minion Cores
  10. Intel Skylake Audio Support For Linux 3.19
Latest Forum Discussions
  1. Speeding up systemd networking service
  2. Major Performance Breakthrough Discovered For Intel's Mesa Driver
  3. Looking for an nVidia GPU, but not sure how well they are supported.
  4. Need some hand holding with upgrading xserver
  5. FPS capped on Linux (AMD fglrx drivers)
  6. Are there an app using HSA ?
  7. The New SuperTuxKart Looks Better, But Can Cause GPU/Driver Problems
  8. XLennart: A Game For Systemd Haters With Nothing Better To Do