Messages in this thread | | | Date | Tue, 25 Jan 2022 19:03:52 +0530 | Subject | Re: [REGRESSION] Too-low frequency limit for AMD GPU PCI-passed-through to Windows VM | From | "Lazar, Lijo" <> |
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On 1/25/2022 5:28 AM, James Turner wrote: > 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 smaller > subset that would be useful? Fwiw, I don't see much in the full drm logs > about the AMD GPU anyway; it's mostly about the Intel GPU. > > All the messages in the system log containing "01:00" or "1002:6981" are > identical between the two versions. > > I've posted below the only places in the logs which contain "amd". The > commit with the issue (f9b7f3703ff9) has a few drm log messages from > amdgpu which are not present in the logs for f1688bd69ec4. > > > # f1688bd69ec4 ("drm/amd/amdgpu:save psp ring wptr to avoid attack") > > [drm] amdgpu kernel modesetting enabled. > vga_switcheroo: detected switching method \_SB_.PCI0.GFX0.ATPX handle > ATPX version 1, functions 0x00000033 > amdgpu: CRAT table not found > amdgpu: Virtual CRAT table created for CPU > amdgpu: Topology: Add CPU node > > > # f9b7f3703ff9 ("drm/amdgpu/acpi: make ATPX/ATCS structures global (v2)") > > [drm] amdgpu kernel modesetting enabled. > vga_switcheroo: detected switching method \_SB_.PCI0.GFX0.ATPX handle > ATPX version 1, functions 0x00000033 > [drm:amdgpu_atif_pci_probe_handle.isra.0 [amdgpu]] Found ATIF handle \_SB_.PCI0.GFX0.ATIF > [drm:amdgpu_atif_pci_probe_handle.isra.0 [amdgpu]] ATIF version 1 > [drm:amdgpu_acpi_detect [amdgpu]] SYSTEM_PARAMS: mask = 0x6, flags = 0x7 > [drm:amdgpu_acpi_detect [amdgpu]] Notification enabled, command code = 0xd9 > amdgpu: CRAT table not found > amdgpu: Virtual CRAT table created for CPU > amdgpu: Topology: Add CPU node > >
Hi James,
Specifically, I was looking for any events happening at these two places because of the patch-
https://elixir.bootlin.com/linux/v5.16/source/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c#L411
https://elixir.bootlin.com/linux/v5.16/source/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c#L653
The patch specifically affects these two. On/before starting VM, if there are invocations of these two functions on your system as a result of the patch, we could navigate from there and check what is the side effect.
Thanks, Lijo
> Other things I'm willing to try if they'd be useful: > > - I could update to the 21.Q4 Radeon Pro driver in the Windows VM. (The > 21.Q3 driver is currently installed.) > > - I could set up a Linux guest VM with PCI passthrough to compare to the > Windows VM and obtain more debugging information. > > - I could build a kernel with a patch applied, e.g. to disable some of > the changes in f9b7f3703ff9. > > James >
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