Radeon RX 6600 Linux Performance Rising Even Higher With Newest Open-Source Driver

[chrisr]

APSM is known to be problematic on some platforms. Forcing it on can cause problems, while using the default settings set up by the bios is safe.

True, but I've been enabling it on this motherboard for years with two earlier graphics cards without any problems, and so I'm inclined to think there is more to this than just ASPM.

I did notice that with ASPM set to "powersave", the screen would dim briefly once or twice while GNOME was logging in, as if the card were fading it out during a period of inactivity. Could an ASPM "event" interrupt something that shouldn't be interrupted?

In fact, ASPM is still enabled because my kernel command line includes these options:

pcie_aspm=force amdgpu.aspm=1

producing these messages in my dmesg log:

[ 0.055387] PCIe ASPM is forcibly enabled

[ 1.028994] acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI EDR HPX-Type3]

[ 1.171047] pci 0000:00:1c.2: ASPM: current common clock configuration is inconsistent, reconfiguring

[ 1.185093] pci 0000:00:1c.4: ASPM: current common clock configuration is inconsistent, reconfiguring

[agd5f]

Still too early to cry "Success!", but I have just managed to run World of Warcraft using a home-compiled 5.15.5 kernel. I think the key change was replacing

CONFIG_PCIEASPM_POWERSAVE=y

with

CONFIG_PCIEASPM_DEFAULT=y

although I cannot explain why.

APSM is known to be problematic on some platforms. Forcing it on can cause problems, while using the default settings set up by the bios is safe.

[chrisr]

Not relevant to graphics.

Still too early to cry "Success!", but I have just managed to run World of Warcraft using a home-compiled 5.15.5 kernel. I think the key change was replacing

CONFIG_PCIEASPM_POWERSAVE=y

with

CONFIG_PCIEASPM_DEFAULT=y

although I cannot explain why.

[agd5f]

Curious - Fedora has loaded these modules:

rpcrdma 331776 2
rdma_cm 131072 1 rpcrdma
iw_cm 57344 1 rdma_cm
ib_cm 143360 1 rdma_cm
ib_core 417792 4 rdma_cm,rpcrdma,iw_cm,ib_cm

I don't recognise these. Could they be relevant please?

Not relevant to graphics.

[agd5f]

If a stock RH kernel works, just use the config from that kernel.

[chrisr]

Those are just PCI bridges built into the GPU. They shouldn't require any special configuration.

Sadly, enabling CONFIG_INTEL_IOMMU_SVM did not make any difference. Nor can I locate any MSI-related options wheich are different between my and Fedora's kernels (except for CONFIG_MSI_WMI, but that's the wrong kind of MSI )

Curious - Fedora has loaded these modules:

rpcrdma 331776 2
rdma_cm 131072 1 rpcrdma
iw_cm 57344 1 rdma_cm
ib_cm 143360 1 rdma_cm
ib_core 417792 4 rdma_cm,rpcrdma,iw_cm,ib_cm

I don't recognise these. Could they be relevant please?

[chrisr]

Those are just PCI bridges built into the GPU. They shouldn't require any special configuration.

OK, thanks.

FWIW, enabling

CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
CONFIG_MEMORY_HOTPLUG=y
CONFIG_MEMORY_HOTPLUG_SPARSE=y
CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y
CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE=y
CONFIG_MEMORY_HOTREMOVE=y

CONFIG_PCI_P2PDMA=y
CONFIG_DEVICE_PRIVATE=y

seem to allow GNOME to login now. The "Fence fallback timer expired" messages still happen when I launch Wine and Battle.net though.

[agd5f]

Thanks for the suggestion, I will compare all of the MSI-related CONFIG settings. I also intend to try enabling

CONFIG_INTEL_IOMMU_SVM=y

to see if that makes a difference too. My motherboard supports PCIE 2.0, but the RX-6600 card also includes these devices:

1478 Navi 10 XL Upstream Port of PCI Express Switch
1479 Navi 10 XL Downstream Port of PCI Express Switch

which suggests my kernel needs PCIE functionality beyond what's on my motherboard.

Those are just PCI bridges built into the GPU. They shouldn't require any special configuration.

[chrisr]

Sounds like potentially a problem with interrupts. Maybe some problems with MSI or MSI-X support in your kernel?

Thanks for the suggestion, I will compare all of the MSI-related CONFIG settings. I also intend to try enabling

CONFIG_INTEL_IOMMU_SVM=y

to see if that makes a difference too. My motherboard supports PCIE 2.0, but the RX-6600 card also includes these devices:

1478 Navi 10 XL Upstream Port of PCI Express Switch
1479 Navi 10 XL Downstream Port of PCI Express Switch

which suggests my kernel needs PCIE functionality beyond what's on my motherboard.

[agd5f]

I have recently bought a Radeon RX6600 card, and it works fine with a stock Fedora kernel (5.15.4-201.fc35.x86_64), but I am having a lot of problems configuring my own kernel to use it! I can only assume that the card has some non-obvious dependencies, possibly for the PCIE bus or memory management? For reference, i am currently using:

CONFIG_DRM_AMDGPU=m
CONFIG_DRM_AMDGPU_CIK=y
CONFIG_DRM_AMDGPU_USERPTR=y
CONFIG_DRM_AMD_DC=y
CONFIG_DRM_AMD_DC_DCN=y
CONFIG_DRM_AMD_DC_HDCP=y
CONFIG_DRM_AMD_SECURE_DISPLAY=y
CONFIG_HSA_AMD=y
CONFIG_HSA_AMD_SVM=y
CONFIG_DRM_AMD_ACP=y

and I have also added:

CONFIG_AMD_IOMMU=y
CONFIG_AMD_IOMMU_V2=m

which provides me with the same kernel modules as the Fedora kernel. However, the GNOME desktop fails during login when using my own kernel, and the dmesg log fills with errors like:

Nov 28 12:32:38 endgame kernel: [drm] Fence fallback timer expired on ring gfx_0.0.0
Nov 28 12:32:38 endgame kernel: [drm] Fence fallback timer expired on ring sdma1
Nov 28 12:32:39 endgame kernel: [drm] Fence fallback timer expired on ring sdma0

The fact that Fedora's kernel works OK must mean that my hardware is fine. Does anyone know of any kernel config options I may have missed please?

Sounds like potentially a problem with interrupts. Maybe some problems with MSI or MSI-X support in your kernel?