3D Nature and Partners Declare ATI drivers Unsuitable for Professional Visualization

Revised July 18, 2006: Catalyst 6.6 public release with fixes!

 

Update July 18, 2006: ATI's latest public release, Catalyst 6.6 has now been thoroughly tested and found to operate correctly for all test cases! Due to the nature of ATI's site structure, It is not possible for us to provide a direct link to download the driver. Instead, go to: ATI's website and download the item referred to as Catalyst Control Center Package (which is 34.8Mb in size). Laptop users with the Mobility Radeon chipset, visit: http://www.ati.com/online/mobilecatalyst/. Check with your IT support staff or systems administrator if you do not have the authority to install drivers. It is unknown when an ATI FireGL driver update will incorporate these bugfixes, but we presume FireGL will receive the same treatment soon. Also, prelimiary reports indicate that the current ATI Radeon drivers for Linux (which are supposed to be the same release as the Windows drivers) may not fix these problems.

Update May 31, 2006: ATI has made available a 'hotfix' driver update to solve these issues. The OpenSceneGraph developer group has completed testing on this hotfix and determined that it does solve the two critical issues reported below. These fixes are not in the current Catalyst 6.5 driver, according to the release notes, but may be in the next public release. Due to the nature of ATI's support site structure, It is not possible for us to provide a direct link to download this hotfix driver. Instead, go to: http://support.ati.com and in the Search field, enter 22262. This will take you to a download page, with a link that says Click here to Download Now. Clicking that link should provide you with a driver update that fixes both issues, even though the description only mentions the VSYNC issue. If your systems administration policies do not permit you to install drivers of this sort, you will need to wait for the public release of the next Catalyst driver (presumably called 6.6) which should be officially WHQL-signed. It is unknown when an ATI FireGL driver update will incorporate these bugfixes, but we presume FireGL will receive the same treatment soon.

Original announcement text preserved below...

May 4th, 2006, Morrison Colorado

3D Nature, a leader in photorealistic landscape visualization, together with a prominent group of 3D visualization developers and users, have taken the drastic step of publicly declaring ATI's Catalyst OpenGL display drivers as unsuitable for professional realtime visualization needs.

All past and current ATI Catalyst drivers for all ATI Radeon series display cards contain several critical bugs that render the hardware unusable in professional 3D visual simulation applications. ATI has been aware of the problems since 2005 but has not fixed the most critical issues, has not announced an ETA for fixing them, or even acknowledged them publicly in their Known Issues for current releases.

The two critical failures are referred to as "VSYNC spinlock" and "compressed SGIS_generate_mipmap failure". Both are documented extensively on the OpenSceneGraph web site:
http://www.openscenegraph.org/osgwiki/pmwiki.php/Tasks/OpenGLConformance
complete with screengrabs and sample code to reproduce the problem.

VSYNC spinlock refers to the situation where the display driver continuously runs the CPU during a wglSwapBuffers() function call when vertical retrace synchronization (VSYNC) is on. This leaves the CPU unavailable to perform other work during this period when it should normally be idle, drastically impairing the performance of modern multi-threaded visualization applications. Other modern display card hardware drivers (3D Labs, NVidia) leave the CPU available during this operation.

The Cow model is very simple and should not consume 100% of the CPU.
Actual draw time is .34ms per frame, the remaining time is wasted by the ATI driver.

Compressed SGIS_generate_mipmap failure describes how the very-common mip-map generation extension, "GL_SGIS_generate_mipmap", is completely broken when using texture compression. Most modern applications generate mipmaps using SGIS_generate_mipmap to improve texture anti-aliasing in 3D scenes. Texture compression is also commonly used to reduce the memory consumption of textures in the scene in order that more or more detailed textures can be resident in the display card, improving scene detail and performance. It is very common to use both of these techniques together in professional visual simulation applications to extract the maximum visual quality and framerate from a given graphics subsystem. The failure of this combination of features on ATI cards means that texture compression is unusable, severely impairing scene performance. Again, other manufacturers do not suffer this problem.

On the left is how the model looks on compliant graphics cards, or ATI card without compression.
On the right is how the model looks using GL_SGIS_generate_mipmap with texture compression on an ATI card.

ATI has been aware of these these issues for quite some time, and has internally filed them as "EPR #151824".

Joining 3D Nature in their protest of ATI's neglect are numerous luminaries of the realtime 3D visualization industry:

Fredrik Ahl, Scalo AB, www.scalo.se
Don Burns, Andes Computer Engineering, www.andesengineering.com
Carlo Camporesi, Institute of Technologies Applied to Cultural Heritage, Italy
Jan Ciger, OpenGL developer
Ben Discoe, project lead, "Virtual Terrain Project" www.vterrain.org
Murray G. Gamble, Director of Modeling & Simulation, Aerospace and Cognitive Engineering (ACE) Laboratory, Carleton University
Roger James - CTO - Virtual Outlooks Ltd.
Gert van Maren, Head of Development, K2Vi Virtual Reality Software, www.k2vi.com
Robert Osfield, Project Lead, OpenSceneGraph, www.openscenegraph.org
Gordon Tomlinson, Consultant, www.3dscenegraph.com
James A. Zack, President, Xtra-Spatial Productions, www.spatialexperts.com

Collectively, we call upon ATI to address these issues immediately, in order that their hardware may be made suitable for professional visual simulation uses.

Current information about this issue will be found at:
http://3dnature.com/ati.html

About 3D Nature:

Since 1992, 3D Nature has developed and marketed professional photorealistic 3D landscape visualization software including World Construction Set, Visual Nature Studio, Scene Express and NatureView Express. 3dnature.com