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 Benchmarking Platform
Phoromatic Test Orchestration

RadeonHD Driver Power Management Improves

AMD

Published on 24 July 2009 03:17 PM EDT
Written by Michael Larabel in AMD
10 Comments

While we just shared that there are now patches available that introduce HDMI audio support for the xf86-video-ati driver, the RadeonHD driver has picked up improvements for power management, an area where previously the xf86-video-ati driver was in a better position. Novell's Matthias Hopf added some power management support for an area of the AtomBIOS that he had reverse engineered, after AMD hadn't provided any public documentation on the matter.

With this new power management code, the xf86-video-radeonhd driver will attempt to read voltage and clock information from the AtomBIOS and then try to figure out the different combinations of voltages and frequencies that will work without leaving the card in a non-functioning state. There is code in place with the RadeonHD driver for controlling the engine clock, memory clock, and VDDC voltage, but right now it's just implemented for making engine clock adjustments.

Not only is it difficult to compute the combinations in which the clocks and voltages can run at in a stable manner, but then applying the changes is also difficult. In order to change the GPU clock, the GPU must first be idling. Similarly, there cannot be any GPU memory accesses performed when the memory clock is about to be changed. Additionally, everything must be idling when the voltage changes. As a result, this work is still far from complete and there is a lot of testing and verification work that needs to go on.

Meanwhile, work has been going into the competing xf86-video-ati driver for the past several months to down-clock the GPU, decrease the PCI Express bandwidth, and carry out other functions in order to conserve small amounts of power.

For those interested in the RadeonHD power management work that is going on, read this mailing list entry.

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 Articles & Reviews
  1. Radeon Linux Benchmarks: Catalyst 15.3 Beta vs. Linux 4.0 + Mesa 10.6-devel
  2. Trying Out The Modern Linux Desktops With 4 Monitors + AMD/NVIDIA Graphics
  3. Turning A Basement Into A Big Linux Server Room
  4. NVIDIA's $1000+ GeForce GTX TITAN X Delivers Maximum Linux Performance
  5. OS X 10.10 vs. Ubuntu 15.04 vs. Fedora 21 Tests: Linux Sweeps The Board
  6. The New Place Where Linux Code Is Constantly Being Benchmarked
Latest Linux News
  1. Debian 8.0 Jessie Gets A Release Date
  2. Firefox 37 Coming Today With Heartbeat, HTTPS Bing
  3. OpenIndiana 2015.03 Updates Its Solaris/Illumos Environment
  4. GNOME 3.16 SDK Runtime Now Available
  5. Initial Intel Braxton Support Might Come To Linux 4.1
  6. Why KDE's KWin Doesn't Integrate Weston/QtCompositor For Wayland Support
  7. Clang Now Supports Targeting The NaCl OS
  8. PC-BSD Updates Its Lumina Desktop (v0.8.3)
  9. Fedora 22 Alpha Now Available For AArch64 & PowerPC64
  10. Systemd Developers Did NOT Fork The Linux Kernel
Most Viewed News This Week
  1. The Big Features Of The Linux 4.0 Kernel
  2. Improved OpenCL Support For Blender's Cycles Renderer
  3. Open-Source Driver Fans Will Love NVIDIA's New OpenGL Demo
  4. Allwinner Continues Jerking Around The Open-Source Community
  5. GNOME 3.16 Released: It's Their Best Release Yet
  6. Ubuntu 15.04 Final Beta Released
  7. Nuclide: Facebook's New Unified IDE
  8. LibreOffice Online: A Cloud Version Of LibreOffice