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

Hybrid Graphics Comes To Linux In Crude Form

Linux Kernel

Published on 01 February 2010 08:23 AM EST
Written by Michael Larabel in Linux Kernel
9 Comments

While the support for graphics processors on Linux in the free software stack has improved a lot over Linux, there still are entire areas of support missing, such as with supporting NVIDIA's SLI or AMD's CrossFire technologies. Additionally, NVIDIA and AMD as well as Intel have been plopping dual GPUs into notebooks. This is not to split the rendering workload, but rather to allow one lower-powered GPU to be utilized when not in engaging in any vigorous tasks and then another performance-oriented GPU to be utilized when such speed is needed. This solution basically provides the best of both words of having maximum battery life but fast performance when needed. However, Linux has not supported this hybrid / switchable graphics technology at all.

Going back to 2008 it was an action item to be worked on of supporting mobile GPU switching with X.Org / Linux and there have been talks about it at other times, but it really hadn't amounted to much. David Airlie though has started playing with this switchable graphics technology on a Lenovo ThinkPad, which combines an Intel and ATI GPU. David Airlie has got this graphics switching to work, but in a rather crude form at this time. He has also published his kernel patch to allow this ACPI-based switching support to work.

David got this working in one day, but this is not true switchable graphics like can be found on Windows. With this rudimentary support, the ATI and Intel kernel mode-setting drivers initial both GPUs upon start-up and for now both GPUs continue to run. Neither of the GPUs actually shut off or are otherwise put into any reduced power state, which actually is eliminating most of the benefits of this feature. Additionally, when switching graphics the X.Org Server needs to be killed and restarted, but it's not seamless switching.

There is also not a clean path to do the switching but rather to initiate the ACPI method switch you need to change to a virtual terminal and write to the switch on the kernel's debug file-system and then change back the run-level. This work also depends on not having a xorg.conf (or one that specifies the GPU/driver) to function.

This work by David is a pure kernel patch and is not changing anything with the X.Org Server itself, since it's simply killing and restarting the display server in the process. Ultimately the X.Org Server needs to gain better support to provide a clean and seamless switching experience.

David does know how to power-down the Radeon GPU using ACPI and for the Intel GPU to potentially put it in a suspended state, but that code is not found in today's patch called the vga_switcheroo. Lastly, David is also going to lobby the GDM developers to have a log-out button for GNOME that says "Switch GPU" to provide a bit more transparent experience without having to manually change run-levels and write to the debugfs switch.

In David Airlie's blog post he adds, "I'm really hoping interested community people can make this actually useful to them on other hw, I won't have permanent access to the W500 to keep this all tested in the future."

Latest Linux Hardware Reviews
  1. Overclocking The AMD AM1 Athlon & Sempron APUs
  2. AMD Athlon 5350 / 5150 & Sempron 3850 / 2650
  3. Upgraded Kernel & Mesa Yield A Big Boost For Athlon R3 Graphics
  4. AMD Athlon 5350 APU On Linux
Latest Linux Articles
  1. A Quick Look At GCC 4.9 vs. LLVM Clang 3.5
  2. Are AMD Athlon/Sempron APUs Fast Enough For Steam On Linux?
  3. AMD Athlon's R3 Graphics: RadeonSI Gallium3D vs. Catalyst
  4. GCC 4.9 Compiler Optimization Benchmarks For Faster Binaries
Latest Linux News
  1. Maynard: A Lightweight Wayland Desktop
  2. Chromium Browser Going Through Growing Pains In Ubuntu 14.04
  3. KDE 4.13 Is Being Released Today With New Features
  4. Trying Out Radeon R9 290 Graphics On Open-Source
  5. Intel Broadwell GT3 Graphics Have Dual BSD Rings
  6. Early Linux 3.15 Benchmarks Of Intel Core i7 + Radeon
  7. Red Hat Releases Its RHEL 7 Release Candidate
  8. New Features Coming To Xubuntu 14.04 LTS
  9. NVIDIA Officially Releases CUDA 6
  10. Google Releases An AutoFDO Converter For Perf In LLVM
  11. Fedora 21 To Evaluate Remote Journal Logging, 64-bit ARM Emulation
  12. Star Citizen Will Be Coming To Linux
Latest Forum Discussions
  1. After Jack Keane, RuseSoft will briing Ankh 3 to Linux through Desura
  2. The GNOME Foundation Is Running Short On Money
  3. Linux Kernel Developers Fed Up With Ridiculous Bugs In Systemd
  4. Bye bye BSD, Hello Linux: A Sys Admin's Story
  5. New tool for undervolt/overclock AMD K8L and K10 processors
  6. How to enable opengl 3.3 on r9 270?
  7. R290x sound problems
  8. radeon-profile: tool for changing profiles and monitoring some GPU parameters