Hi, 10 years later, the situation doesn't have changed much. At least for AMD and NVidua GPUs, you need vendor packages from external sources to use OpenCL and get a performance gain. In the current state, the rusticl OpenCL implementation, which is part of Mesa, seems to lack features and/or is still too buggy. At least it can not be used for darktable and AMD support has to be enabled by setting an environment variable.
This is a general issue that the darktable package can not change. So I propose to close this bug. Regards, Tino
