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

Intel Flip-Flops Again: RC6 Disabled For Linux 3.2

Linux Kernel

Published on 28 December 2011 07:57 PM EST
Written by Michael Larabel in Linux Kernel
3 Comments

Ouch, Intel at the last minute has -- once again -- had to disable RC6 power savings support from their open-source Linux graphics driver for Sandy Bridge hardware.

Earlier this month I wrote that Intel would be attempting to enable RC6-by-default for Sandy Bridge and Ivy Bridge graphics processors in the forthcoming Linux 3.2 kernel. RC6 is capable of saving power for mobile (and desktop) systems by allowing the integrated graphics processor to rest in a lower power-state, while at the same time is capable of boosting OpenGL performance.

Earlier this month I questioned whether Linus Torvalds would allow Intel RC6 to be enabled by default outside of the merge window considering this feature has been problematic in the past -- causing stability issues and hangs for some systems -- and he was already mad at one 3.2 DRM pull, but it ended up getting accepted.

Along with that merge this month was enabling of semaphores by default, which was then reverted last week over regressions. Now this week Keith Packard sent over a patch to Linus Torvalds to revert the RC6 by default.

So the Linux 3.2 kernel will not have RC6 by default for Sandy Bridge since it's still causing problems for some systems with this Linux driver, one year after the hardware first shipped. This commit is what does the flip-flop, again (it's been a similar story before).

Those wanting to take advantage of this feature and aren't hit by system freezes, you can pass i915.i916_enable_rc6=1 as a kernel command-line parameter to enable this power conservation feature.

Maybe with the Linux 3.3 kernel Intel will finally get lucky?

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. Ubuntu 15.04 Offers Faster OpenGL For AMD Radeon GPUs On Open-Source
  2. Ubuntu 15.04 Brings Some Graphics Performance Improvements For Intel Haswell
  3. Sub-$20 802.11n USB WiFi Adapter That's Linux Friendly
  4. The Lenovo T450s Is Working Beautifully With Linux
  5. Linux 4.0 SSD EXT4 / Btrfs / XFS / F2FS Benchmarks
  6. Linux 4.0 Hard Drive Comparison With Six File-Systems
Latest Linux News
  1. GCC 5.2 Will Come In Two To Three Months
  2. AMD FP3 Motherboard Ported To Coreboot
  3. The Difference In Optimizations Between NIR & GLSL
  4. OpenMandriva Lx 3 Alpha: Adds UEFI Support, Defaults To LXQt
  5. Systemd Kills Off Shutdownd
  6. There's Now More Than 1,100 Games On Steam For Linux
  7. Btrfs In Linux 4.1 Has Fixes For File-Systems Of 20 Terabytes & Up
  8. Microsoft's CoreCLR Now Works On FreeBSD
  9. Unigine 2.0 Beta 2 Brings PBR, SSR, Kinect 2 Support
  10. KDBUS Still Hasn't Been Pulled, Might Not Land For Linux 4.1
Most Viewed News This Week
  1. AMD Releases New "AMDGPU" Linux Kernel Driver & Mesa Support
  2. Ubuntu's Desktop-Next Switching From .DEBs To Snappy
  3. EXT4 In Linux 4.1 Adds File-System Level Encryption
  4. My Favorite Computer Desk Of The Past Decade For Less Than $100
  5. AMD Open-Sources "Addrlib" From Catalyst
  6. Library Operating System (LibOS) For Linux Still Being Pursued
  7. Linux-Powered Endless Computer Raises $100k+ In A Few Days
  8. Features Thus Far For The Linux 4.1 Kernel