Joe_H wrote:The HD 7700 series cards are based on the GCN 1st generation Verde chips. OpenCL support for those was dropped by AMD for Linux several years ago, you would have to load older versions of the drivers and may be capped at Ubuntu 16.04 or earlier.
Yes, I looked closer at the AMD Linux driver release notes, and although version 18.20 of the AMD Radeon pro drivers explicity supports the Radeon HD 7700 series cards,
the release notes also lists about its components: "OpenCL™1.2 (not supported for 1st generation GCN products)", as you say.
For the giggles, I installed Ubuntu 16.04 and 14.04 in a libvirt KVM and tried the last Ubuntu drivers that don't include the note about non-support for 1st gen GCN.
The good news is that on 16.04 the driver installs and PCI passthrough with IOMMU from the GPU to the virtual machine works. The bad news is that in the case of 16.04 I got the same type of error: OpenCL installs and appears to work, including clinfo, but FAH makes bad work units. And in the case of 14.04, installation failed on compiling/including the DKMS module, and no amount of kernel source packages seeemd to cure this - perhaps I just haven't tried the correct minor version of the kernel yet.
To confirm the qemu/libvirt host was set up correctly, I installed Windows 10 as a guest OS, and it appears to run the GPU fine in FAH, and it even seems to run the GPU faster than it did natively in the old Windows PC. CPU overhead is negligble in the host OS - except when Windows Update starts running.
I might test with an different version of the Linux kernel in Ubuntu and Centos in libvirt again, as the memory overhead of running a full Windows installation just to feed work to an old GPU is rather ridiculous.