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

NVIDIA Releases A Bit More Open GPU Documentation

NVIDIA

Published on 25 October 2013 04:17 AM EDT
Written by Michael Larabel in NVIDIA
9 Comments

Last month NVIDIA announced they would begin providing open-source GPU documentation and ultimately supporting the reverse-engineered open-source Nouveau graphics driver project for their Linux desktop customers. NVIDIA released some basic documentation in that initial push and now they have followed up with a tiny bit more documentation.

The new "open NVIDIA documentation" that was made public this week isn't as exciting as AMD's 3D/Compute GPU documentation but the new text file documentation is helpful if you're a GK104 GPU owner and have been having issues with Nouveau.

The new documentation file made public is basically making public an error in the GK104 video BIOS that could cause problems for users of non-official NVIDIA drivers.

It turns out that a diagnostic setting was left enabled in the production vBIOS builds of some GK104-based graphics cards, including the GeForce GTX 680M, GeForce GTX 670MQ, Quadro K4000M, Quadro K4000M, and some other related GPUs. The diagnostic setting left on is where the vBIOS will turn a display output to red in case of display engine under-flows. The display would be red or just red pixels where pixels are missing.

Display engine under-flows is an occurrence where the current GPU performance state limits the GPU video memory bandwidth to an amount lower than the current streaming requirements for the display engine, i.e. the driver aggressively set the memory frequency too low. By making the screen red in debug builds of the video BIOS, it's easy for developers to see this problem is happening.

So NVIDIA's new documentation is just making known this situation and that some video BIOSes may have the setting on. For resolving it, the NVIDIA Linux driver disables the setting and so for helping Nouveau, NVIDIA pointed out the four per-head registers that can be set to avoid this debug feature. At least their documentation properly documented these few registers to address a problem a small number of Nouveau Linux users have encountered. From another perspective, this could potentially be of use to the Nouveau developers in being able to tap this feature for better testing when dealing with their troubled re-clocking support.

Those interested in seeing NVIDIA's open documentation can find it from the NVIDIA.com FTP server.

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. Intel Xeon E5-1680 v3 & E5-2687W v3 Compared To The Core i7 5960X On Linux
  2. Intel 120GB 530 Series SSD Linux Performance
  3. Btrfs/EXT4/XFS/F2FS RAID 0/1/5/6/10 Linux Benchmarks On Four SSDs
  4. AMD's Windows Catalyst Driver Remains Largely Faster Than Linux Drivers
Latest Linux Articles
  1. Mesa Git Yields Performance Improvements For Newer AMD GPUs
  2. Apple OS X 10.10 vs. Ubuntu 14.10 Performance
  3. Mesa 10.5-devel Brings Some Intel Haswell HD Graphics Changes Over Mesa 10.3
  4. NVIDIA vs. Nouveau Drivers With Linux 3.18 + Mesa 10.4-devel
Latest Linux News
  1. Qt 5.4 Planned For Release On 9 December
  2. Meizu's Ubuntu Phone Not Expected Until Early Next Year
  3. DragonFlyBSD 4.0 Drops i386 Support, Improves Graphics
  4. Expensive "Free/Libre Software Laptop" Uses A NVIDIA GPU
  5. QEMU 2.2-rc3 Released, Final Release Pushed Back By Couple Days
  6. 64-bit ARM FreeBSD Support Is Taking Shape
  7. GCW Zero Starts Seeing New Game Releases
  8. Intel's Cherry Trail Delayed To Next Year
  9. Bq Introduces More Android Devices, But Still No Ubuntu Phones
  10. Qt 5.4 Release Candidate Expected Later This Week
Latest Forum Discussions
  1. Updated and Optimized Ubuntu Free Graphics Drivers
  2. Hurrican SDL Port
  3. Roadmap to Catalyst 14.10 ?
  4. how to configure module phoromatic ?
  5. PulseAudio 6.0 Is Coming & Other Linux Audio Plans For The Future
  6. Debian Developer Resigns From The Systemd Maintainership Team
  7. Cant get working Kaveri APU - A10-7850k
  8. Script for Fan Speed Control