Unbuntu 18.04 and AMD driver -- need help

[Joe_H]

Thanks for reporting back. I mentioned the "rabbit hole" I started down once, looks like you may have run into that bit I mentioned about the last Linux driver with OpenCL support giving incorrect results for calculations. You got a bit further than I did.

[MeeLee]

do the opencl-dev packages help?
They seem to be somewhat universal?

[gunnarre]

No, they don't help either of the issues that's been covered in this thread. This is about AMD's drivers and its OpenCL support.

[gunnarre]

I made a virtual machine instance for the Radeon 7770 HD based on Ubuntu 14.04 and the Catalyst 15.7 drivers from AMD. I downgraded the kernel to 3.19.0-25, installed the fglrx_core .deb-file and its dependencies. I had to copy the file /etc/ati/amdpcsdb.default from fglrx_ (non-core) .deb file - otherwise clinfo would only work once and then segfault. I also installed fglrx-dev and ocl-icd-opencl-dev, but I'm not sure of that was necessary. The CPU usage seems to be similar as under Windows 10, depending on the work unit. Guest machine memory usage is less than half, down from over 2GB to between 380 and 760 MB when folding.

[wrothran]

I made a virtual machine instance for the Radeon 7770 HD based on Ubuntu 14.04 and the Catalyst 15.7 drivers from AMD. I downgraded the kernel to 3.19.0-25, installed the fglrx_core .deb-file and its dependencies. I had to copy the file /etc/ati/amdpcsdb.default from fglrx_ (non-core) .deb file - otherwise clinfo would only work once and then segfault. I also installed fglrx-dev and ocl-icd-opencl-dev, but I'm not sure of that was necessary. The CPU usage seems to be similar as under Windows 10, depending on the work unit. Guest machine memory usage is less than half, down from over 2GB to between 380 and 760 MB when folding.

any chance you have a guide that can be followed in order to do this? does this involve a gpu passthrough?

[gunnarre]

Yes, it involves passthrough. If you're going to use a regular (not EPYC/Threadripper) motherboard, you might actually want to pass through the primary PCIe slot, and put the GPU for the host OS in a chipset slot.

Here's a link to a guide, with some additional notes on the difference in host system kernels.

Edit: Here's a guide for setting up GPU passthrough when your Linux distro has vfio as an optional kernel module: Using GPUs in KVM Virtual Machines. Note that these instructions need modification if the kernel already has vfio compiled in - in that case, you need to set the vfio-settings in GRUB rather than in the modprobe.d settings. For example: (Replace the PCIe device identifiers with those you need to export from your system - here both the audio and video from the Radeon 7770HD.):

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GRUB_CMDLINE_LINUX_DEFAULT="amd_iommu=pt vfio-pci.ids=1002:683d,1002:aab0"

You can even run the host machine in headless mode and export every single graphics card to a guest, but you then have to add

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video=efifb:off

to the GRUB boot options to prevent the host OS from grabbing the graphics card on boot.