Thumbnail and export artifacts with OpenCL and Radeon HD7870
I've had quite a few problems getting OpenCL to work on my system. Have a look here.
At the moment I am using proprietary driver 18.20 OpenCL only and open source radeon driver for the rest.
Using "export GPU_FORCE_64BIT_PTR=1" OpenCL gets detected by darktable and is used as well but produces serious artifacts in thumbnails and exported images (see attached files).
Artifacts are even produced with all modules disabled in darkroom. With OpenCL disabled everything works as expected.
Is there anything I can try to get rid of those artifacts other than disabling OpenCL?
Thank you in advance!
#2 Updated by Simon Raffeiner 4 months ago
I'm using Arch Linux with AMDGPU-PRO 18.30 on a Radeon RX570 and there are no issues, so at least this doesn't seem to be a generic AMD/OpenCL issue.
Any ideas why you have to set GPU_FORCE_64BIT_PTR=1 to get darktable to see the card? This parameter only seems to tell the GPU driver to use 64 bit pointers so an application can allocate the full video memory if you have 4 GB or more, but your card only has 2 GB of VRAM. darktable can work with 2GB of VRAM (at least it did so for a year with my GTX950), so I wonder why it doesn't offer the card without the environment variable?