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

Radeon DRM: Dynamic Power Management Updates

AMD

Published on 05 July 2013 06:55 PM EDT
Written by Michael Larabel in AMD
80 Comments

The DRM pull request has yet to be submitted for the Linux 3.11 kernel and already there is another revision to the Radeon DRM kernel driver to be submitted. This latest Radeon DRM work provides additional dynamic power management fixes and some new sysfs features.

For open-source AMD Linux desktop users, the Linux 3.11 kernel is going to be spectacular as it finally brings Radeon dynamic power management support. While not yet enabled by default (the radeon.dpm=1 module parameter is needed for now), this finally provides dynamic re-clocking (like PowerPlay) so that GPUs can dynamically adjust their clock speeds and voltages based upon load. This is also good for APUs and newer GPUs so that the hardware can ramp up to its designated frequencies rather than being stuck to their boot frequencies.

Anyhow, on Friday AMD's Alex Deucher sent in another revised Radeon DRM driver. This revised code for the DRM subsystem in the Linux 3.11 kernel provides some dynamic power management fixes. The nine fixes include setting default clock speeds for AMD Radeon HD 7000 "Southern Islands" graphics processors when dynamic power management is enabled, support for 3D performance states on older GPUs, and adding in support for forcing performance levels.

Debugging entries were already added to an earlier revision for finding out the current power management state. With today's code, The new sysfs support allows forcing specific power levels within a power state. The forceable options allow for values of "auto" for all levels being enabled, "low" for forcing the lowest power level, and "high" for forcing the highest power level.

In terms of the 3D performance states for older GPUs, Deucher's commit message explains:
Certain older rv770 asics have both a performance and a 3D performance state rather than just multiple performance levels in the state power state. The current code would select the performance state rather than the 3D performance state when the "performance" profile was selected. This change switches to the "balanced" profile by default which ends up being the internal performance profile. When the user selects the "performance" profile, it selects the internal 3D performance state so the user can select the higher performance modes.

For most asics this changes nothing. For certain rv770 asics with static performance and 3D performance states, this allows you to select between then using by selecting the "balanced" and "performance" dpm profiles.

More details on these latesr Radeon DRM DPM fixes can be found via this mailing list message or browsing Radeon's drm-next-3.11.

Once Linux 3.11-rc1 is out, Radeon Dynamic Power Management benchmarks will begin at Phoronix.

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. AMD Kaveri: Open-Source Radeon Gallium3D vs. Catalyst 14.12 Omega Driver
  2. 12-Way AMD Catalyst 14.12 vs. NVIDIA 346 Series Linux GPU Comparison
  3. AMD Catalyst 14.12 Omega Driver Brings Mixed Results For Linux Users
  4. 6-Way Winter 2014 Linux Distribution Comparison
Latest Linux News
  1. MIPS R6 Architecture Now Supported By GCC
  2. LowRISC To Feature Tagged Memory & Minion Cores
  3. Intel Skylake Audio Support For Linux 3.19
  4. After 10+ Years, NetworkManager Reaches v1.0
  5. VDPAU Updated To v0.9
  6. An Open Hardware Random Number Generator Proposed
  7. LLVM 3.6 Will Be Branched Next Month
  8. Opera Browser Puts Out Linux Updates For The Holidays
  9. GNOME Shell 3.15.3 Adds Support For High-Contrast Themes
  10. Linux 3.19: ThinkPad Muting Redone, New Dell Backlight Support, Acer Is Banging
Latest Forum Discussions
  1. XLennart: A Game For Systemd Haters With Nothing Better To Do
  2. Need some hand holding with upgrading xserver
  3. Updated and Optimized Ubuntu Free Graphics Drivers
  4. Debian init discussion in Phoenix Wright format
  5. The New SuperTuxKart Looks Better, But Can Cause GPU/Driver Problems
  6. FPS capped on Linux (AMD fglrx drivers)
  7. Are there an app using HSA ?
  8. Bench specific mount point