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

Semaphores Continue Biting Intel Linux Users

Intel

Published on 23 December 2011 04:50 PM EST
Written by Michael Larabel in Intel
3 Comments

It turns out the semaphore issues for Intel Sandy Bridge Linux users continues to be present and it's resulting in the patch from the recent Intel merge having to be changed at the last minute within the Linux 3.2 kernel.

With the Linux 3.2-rc6 kernel, the use of semaphores were flipped on when the Intel I/O re-mapping is turned off. But it turns out that semaphores on Sandy Bridge hardware is still problematic.

For those that don't recall, semaphore issues borked the Linux 2.6.39 kernel at the last minute for Sandy Bridge owners too. Semaphores also caused problems during the Linux 2.6.38 kernel. With the Linux 3.2 kernel, it was attempted to flip it back on again for Sandy Bridge and Ivy Bridge hardware, but there's at least one report of hardware hanging when this feature is enabled.

This option though can at least be easily toggled using the i915.semaphores=1 kernel module parameter. (The 2.6.39 Phoronix article explains the issue in greater detail.)

Due to this problem, Keith Packard just sent in a Friday afternoon patch to turn off semaphores by default for Sandy. Semaphores for Ivy Bridge is still left on, which hopefully means the support is more reliable there or at least with their current pre-production development systems as the IVB hardware is still a few months from shipping to the public.

The patch changing the default can be found on the Linux kernel mailing list.

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. Trying Out The Modern Linux Desktops With 4 Monitors + AMD/NVIDIA Graphics
  2. Turning A Basement Into A Big Linux Server Room
  3. NVIDIA's $1000+ GeForce GTX TITAN X Delivers Maximum Linux Performance
  4. OS X 10.10 vs. Ubuntu 15.04 vs. Fedora 21 Tests: Linux Sweeps The Board
  5. The New Place Where Linux Code Is Constantly Being Benchmarked
  6. 18-GPU NVIDIA/AMD Linux Comparison Of BioShock: Infinite
Latest Linux News
  1. Firefox 37 Coming Today With Heartbeat, HTTPS Bing
  2. OpenIndiana 2015.03 Updates Its Solaris/Illumos Environment
  3. GNOME 3.16 SDK Runtime Now Available
  4. Initial Intel Braxton Support Might Come To Linux 4.1
  5. Why KDE's KWin Doesn't Integrate Weston/QtCompositor For Wayland Support
  6. Clang Now Supports Targeting The NaCl OS
  7. PC-BSD Updates Its Lumina Desktop (v0.8.3)
  8. Fedora 22 Alpha Now Available For AArch64 & PowerPC64
  9. Systemd Developers Did NOT Fork The Linux Kernel
  10. PulseAudio 7.0 To Enable LFE Remixing By Default
Most Viewed News This Week
  1. Introducing The Library Operating System For Linux
  2. Improved OpenCL Support For Blender's Cycles Renderer
  3. Allwinner Continues Jerking Around The Open-Source Community
  4. Open-Source Driver Fans Will Love NVIDIA's New OpenGL Demo
  5. GNOME 3.16 Released: It's Their Best Release Yet
  6. Systemd Change Allows For Stateless Systems With Tmpfs
  7. Ubuntu 15.04 Final Beta Released
  8. Nuclide: Facebook's New Unified IDE