Open-Source ATI R500 PowerPlay Support
Written by Michael Larabel in AMD on 8 October 2008 at 12:09 PM EDT. 18 Comments
Behind open-source 3D acceleration for the ATI R600 and R700 series, improved power management has been a much sought after feature among those using the open-source xf86-video-ati and xf86-video-radeonhd drivers. There has been Dynamic Clocks support since earlier this year, but it's not nearly as advanced PowerPlay found within the Catalyst driver. We are now though getting closer to reaching open-source PowerPlay support.

This morning on the RadeonHD mailing list, Yang Zhao has proposed patches that add initial PowerPlay support to the xf86-video-radeonhd driver for the R500 series. The R600/700 series is not yet supported or tested.

These patches are based upon the original work of Alex Deucher with an experimental branch he started earlier for improved power management with the xf86-video-ati driver. Powering most of PowerPlay is the AtomBIOS video abstraction layer to supply supported voltages and frequencies that the specific graphics processor is capable of running.

Due to the lacking infrastructure, right now there is no real-time PowerPlay state changing support. To define a power mode to run at, it must be done through the xorg.conf with the PowerPlayMode option.

These patches come with a big warning: "NO GUARANTEES ARE MADE THAT THE ADDED CODE WILL FUNCTION AS EXPECTED. YOUR EXPERIENCE MAY VARY. VOLTAGE AND CLOCK SETTINGS ARE CHANGED BY THE NEW CODE, AND THIS MAY BE DANGEROUS TO YOUR HARDWARE. TEST AT YOUR OWN RISK."

As no PowerPlay documentation has yet to be published by AMD and these patches have experienced limited testing with the R500 series (and the leading focus is R600/700 3D support), don't expect them to appear in the master branch of this Novell-powered open-source ATI driver anytime soon. Should you be interested in these experimental patches they can be found here.
About The Author
Author picture

Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter or contacted via MichaelLarabel.com.

Related AMD News
Popular News
Trending Reviews & Featured Articles