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

What Was Decided With S3TC & Floating Points For Mesa

Mesa

Published on 09 March 2011 08:25 AM EST
Written by Michael Larabel in Mesa
23 Comments

Last week I mentioned that a developer called for a discussion about merging the OpenGL floating point textures and render targets branch into mainline Mesa. This code has been ready for a while but hasn't been merged due to patent concerns, but to alleviate that while pushing the code forward, the proposed idea was to add a --enable-patented build option. Over the weekend, the discussion continued and it was then also proposed to merge the S3TC texture compression work (another feature where developers are concerned about patent infringement) and to conceal that behind the new build option too. So what happened since and did the work make it into the mainline Mesa Git repository?

On Monday, VMware's Jose Fonseca didn't outright reject the floating point work (email), but as far as the implementation impacting LLVMpipe are implemented, he doesn't want that driver to have the support in its current form. The reason for this is not due to legal concerns with VMware developing the LLVMpipe driver, but because of performance reasons for how it's implemented right now with the most common textures being slower. In fact, Jose is fine with the branch being merged and the OpenGL floating point extensions being enabled by default for LLVMpipe, Softpipe, and the classic Mesa software rasterizer. These are all of the Mesa / Gallium3D drivers that don't work in tandem with a GPU but rather are software/CPU-based.

How can they get away with enabling it by default for software drivers without worrying about legal backlash? Because there is prior art of sampling/rendering floating point textures purely in software, which is admitted by the patent holder. For the hardware drivers is where it becomes a different story.

David Airlie commented on the proposal to merge the libtxc_dxtn (S3TC) library into Mesa to basically counter this idea. With the S3TC library, it's built as a separate library that can plug-in to Mesa. This isn't possible with the floating point work, which is why it needs to be integrated with core Mesa. By integrating the S3TC library into core Mesa, it then means users must always rebuild Mesa rather than just dropping in a shared library. Users right now need to build the S3TC library anyways since the library can't be redistributed in binary form.

But that's basically been about it as far as the S3TC / floating point Mesa discussion has gone in recent days; the discussion has basically died yet again.

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. An Open Hardware Random Number Generator Proposed
  2. LLVM 3.6 Will Be Branched Next Month
  3. Opera Browser Puts Out Linux Updates For The Holidays
  4. GNOME Shell 3.15.3 Adds Support For High-Contrast Themes
  5. Linux 3.19: ThinkPad Muting Redone, New Dell Backlight Support, Acer Is Banging
  6. KVM Drops Support For IA64 While Adding Various x86 Improvements
  7. GCC 4.8.4 Officially Released
  8. FSF's High Priority Project List Now Has A Committee
  9. Details On Using OpenACC & GPUs With GCC
  10. Ubuntu 15.04 Alpha 1 For Its Various Flavors
Latest Forum Discussions
  1. Need some hand holding with upgrading xserver
  2. Debian init discussion in Phoenix Wright format
  3. The New SuperTuxKart Looks Better, But Can Cause GPU/Driver Problems
  4. XLennart: A Game For Systemd Haters With Nothing Better To Do
  5. FPS capped on Linux (AMD fglrx drivers)
  6. Are there an app using HSA ?
  7. Bench specific mount point
  8. Tool for measuring FPS in games