The open-source AMDGPU KFD driver in the Linux kernel supports compute, including with the RX 580 (Polaris). It's true that AMD dropped official support for that hardware and has been closing Polaris-specific bugs as wont-fix. The last ROCm release that AMD validated on Polaris hardware was ROCm 3.5 (June 2020).

I've packaged the test suites of the ROCm math libraries for Debian Trixie and have personally donated a selection of Fiji and Polaris hardware for the Debian AI Team's CI. It's beyond my abilities to fix everything wrong on old hardware, but I'm hoping that having publicly accessible test logs will at least help people to understand what works and what doesn't.

Of course, it always helps if the community contributes. Debian would certainly be interested in bug reports and patches for Polaris. Users with hardware no longer supported by AMD may find it easier to work with their distro package maintainers than with AMD directly.

> And there are no open source drivers for compute.

Well, technically ROCm is open source (although it comes across more as a "dump source code releases every now and then" to me.)

Also, the link is from the Mesa project, which is working on an OpenCL frontend to the driver called rusticl. It's not yet stable or enabled by default, but if you get a build of it, you can try setting the environment variable `RUSTICL_ENABLE=radeonsi` and it should sort-of work (on any Radeon HD 7000 or Radeon R7/R9/RX GPU!)

iirc the rusticl developers are even hoping/planning to get HIP (via chipStar) and SYCL (via Intel's compiler) working on top of rusticl.