Since we are on the subject, I think I may help you debug this issue once and for all:
The bug is about an OpenCL implementation on a Render Engine (Cycles) in Blender
Versions of Blender that have this bug:
Download of Blender: Official Blender Releases
In version 2.65 and probably on the next release too, OpenCL is / will be deactivated because of this bug.
Operational Systems known to have this Bug:
Windows 8: x86, x86_64
Windows 7: x86, x86_64
Windows XP: x86, x86_64
Ubuntu 12.04 LTS: x86, x86_64
Ubuntu 12.10: x86, x86_64
Thread on Blender forums about this bug:
File to test the bug:
Mike Pan BMW Scene
But any file should reproduce the bug. Even the startup cube when set to render in Cycles
Hardware that the bug shows:
AMD / ATI GPU cards OpenCL
Notice that this bug DOES NOT APPEAR on NVidia GPU OpenCL implementation neither on Intel/AMD CPU OpenCL implementations.
Latest driver tested that show the bug:
Catalyst Software Suit 13.1 for any OS
Catalyst Software Suit 13.2 Beta 6 for any OS
Steps to reproduce Bug #1:
Open the desired blender scene;
On the top middle, change from Blender Render to Cycles Render;
On the top left, go to File > User preferences > System;
Choose OpenCL; (now you can either close this windows or save)
On the left middle, change the feature Se from Supported to Experimental (Now you are compiling with OpenCL)
Right bellow, change CPU to GPU Compute;
Click on Render, a little above;
Description of Bug #1 (May be more than only one bug, don't know):
Long time to compile the OpenCL kernel.
RAM usage going to the maximum, even crashing the program.
Scene not rendering (Black frame);
Sometimes, a scene may render (Depends on the situation - Read the forums mentioned above) but the colors are wrong.
OpenCL kernel compiling for each frame (If its an animation).
OpenCL kernel compiling each time you click on render.
Long time of wait between the finished OpenCL kernel and the startup of the Render (Have no Ideia of what this might be, but only happens on AMD GPUs)
Textures does not work with AMD GPUs with OpenCL.
This bug is more dificult to reproduce, but nevertheless it's there. Textures does not work with AMD/ATI but work with other OpenCL implementations;
I hope this info helps you guys solve this issues. Blender is a very powerfull Open Source engine and it would be nice to see some support from your end to make it work properly on your hardware. Any questions, I'm here to answer.
From the preliminary test of the bootleg driver, I hear from the testers that mikepan is working without crashing.
I will confirm this again tomorrow (its a local holiday here today)
Textures stuff is new. we need a repro case for that...
I've made a little research. Textures problems were related to older versions (2.62 and before), and since 2.63 and above are not working with AMD/ATI OpenCL compilers at all (Some trick can be made here, but it didn't have the corrections of 2.63), I can't say for sure that textures aren't working. Maybe if you could test with your driver.
Simple image texture on the default cube, rendered with Cycles on OpenCL for AMD. It's quite simple and there's a lot of tutorials out there. Remember to test on versions 2.63 or up.
We all apreciate you effords, very much!
I guess we are still stuck with the large memory requirements of the blender software. Although, the software is no longer crashing(with internal drivers), it is giving Errors while OpenCL compilation.
I ran the blender software without BMW file. I checked the commandline window showing the log. It can be opened from the window menu in the blender. It gives "OpenCL compilation failed : Insufficient Private Resources!"
I ran the Blender with Mike’s BMW file, and the program gives the same error again.
I have not been able to see the rendered BMW using OpenCL. Blender always shows black screen, which looks reasonable as kernel compilation itself is failing. We are still working on solving this issue. Appreciate your patience on this.
This happens in the AMD drivers available for the public also. The software does no crashing if you wait until the end. It gives "OpenCL compilation failed : Insufficient Private Resources!" too
Thank you and the Engineers behind, looking to fix these issues.
My guess would be memory leaking, from the OpenCL compiler. Perhaps it would be easier to debug the compiler by looking into Blender code, compiling it and deactivate piece by piece. Someone within the Blender developers should be able to provide assistance, if required.
If you, or any of the Engineers could get in touch with the main Cycles developer, Brecht van Lommel, it might be easier to debug also.
I can't state my appreciation for what you are doing for us. Thank you!
You are most welcome. We can't thank you all enough for extending support and more imporatntly for your patience.
I will venture into blender forums and see if I can connect the developer with the engineering team.
May be, they could solve this easily.
I have one last question:
1. I know Blender is written for CUDA as well. But, Have you ever compiled this for NVIDIA's OpenCL platform?
Can you share your results?
The threads below shows the status and compares the rendering speed between CUDA and Nvidia's OpenCL on various platforms.
It may be useful for research.
Thank you Germano. Will pass it on.
As I can see, mikepan blend (bmw) works on nvidia Opencl platform.
Do you have any data on how much memory their OpenCL compilation take (and how long do they take?)
I will see if I can get a local setup here to measure it.... But, if you have some ready made data - it will be useful.