Big Sur OpenCL changes on AMD GPUs

Question

Created Nov ’20

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Hi everyone, I'm having a problem after Big Sur installation. I'm a Blender and LuxCore renderer user. Before upgrading I was on Mojave and Catalina and the renderer worked fine.

I'm having trouble with the LuxCore OCL rendering and I got an OpenCL driver error:

OpenCL driver API error (code -30, file:/Users/runner/work/1/s/src/luxrays/utils/ocl.cpp, line: 366): CLINVALIDVALUE

Other Big Sur user with Radeon VII can render without any issues on OCL. There were probably some driver changes to the AMD GCN 1.0 GPUs but now it's not possible for me to use the renderer.

My specs:
iMac 5k late 2014
i5 24 GB RAM
AMD Radeon R9 M290X (GCN 1.0)

Is there any chance Apple will fix it? Or is there any solution for that? Also did anyone experience issues with OpenCL on Big Sur?

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Answer 1

sbrodhead OP

Nov ’20

Based on the info you have posted, this is a LuxRays bug. The referenced file is one of their own internal source files.

I am the author of Fractal Architect for Mac and iOS. I am not having any issues with my own app. In fact, it looks like Apple has fixed issues I reported back in Catalina.

I have had an OpenCL app on MacOS since 2009. And yes OpenCL has been broken 5 years ago when El Capitan was released, but since then it has been robust for single GPU renders. OpenCL has been problematic for multiple GPU rendering, whereas Metal works properly.

I have not yet retested the multiple GPU kernel scheduling bug in Big Sur.

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Answer 2

Aegwyng OP

Dec ’20

Hi, it is not the same bug, but I'm having problems with my Radeon VII every time I eject it from my MacBook (it gets frozen and after a minute restarts itself).

Also it is not properly recognized by MacOS Big Sur. Before the update it was listed in graphics section on "about this Mac", now it is not listed there anymore. I think Apple removed the support for it.

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