Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM

2022-01-22 Thread James Turner
> Are you ever loading the amdgpu driver in your tests? Yes, although I'm binding the `vfio-pci` driver to the AMD GPU's PCI devices via the kernel command line. (See my initial email.) My understanding is that `vfio-pci` is supposed to keep other drivers, such as `amdgpu`, from interacting with t

Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM

2022-01-24 Thread James Turner
Hi Lijo, > Could you provide the pp_dpm_* values in sysfs with and without the > patch? Also, could you try forcing PCIE to gen3 (through pp_dpm_pcie) > if it's not in gen3 when the issue happens? AFAICT, I can't access those values while the AMD GPU PCI devices are bound to `vfio-pci`. However,

Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM

2022-01-25 Thread James Turner
Hi Lijo, > Not able to relate to how it affects gfx/mem DPM alone. Unless Alex > has other ideas, would you be able to enable drm debug messages and > share the log? Sure, I'm happy to provide drm debug messages. Enabling everything (0x1ff) generates *a lot* of log messages, though. Is there a sm

Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM

2022-03-07 Thread James Turner
Hi Thorsten, My understanding at this point is that the root problem is probably not in the Linux kernel but rather something else (e.g. the machine firmware or AMD Windows driver) and that the change in f9b7f3703ff9 ("drm/amdgpu/acpi: make ATPX/ATCS structures global (v2)") simply exposed the und

Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM

2022-03-14 Thread James Turner
Hi all, I've confirmed that changing the `amdgpu_atif_pci_probe_handle` function to do nothing does make the GPU work properly in the VM. I started with f9b7f3703ff9 ("drm/amdgpu/acpi: make ATPX/ATCS structures global (v2)") and changed the function implementation to: static bool amdgpu_atif_pci_

Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM

2022-03-21 Thread James Turner
>>> Right, interference from host drivers and pre-boot environments is >>> always a concern with GPU assignment in particular. AMD GPUs have a >>> long history of poor behavior relative to things like PCI secondary >>> bus resets which we use to try to get devices to clean, reusable >>> states for