B550 Taichi ACS enable possible£

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   Hi

I have two video cards and a 10Gbe NIC in my system. I have been struggling to get it to work right when using PCI passthrough for one of the GPUs. The problem stems from the fact that the system assigns both the 10Gbe NIC and the main GPU to the same IOMMU group. I can't pass the NIC through to the VM, but that is what the system needs since you can't assign only some of the members of the IOMMU group.

It sounds like the normal way to handle this is by enabling ACS on the mono. But I don't see anyway to do that in my BIOS. I'm already up to version 2.62. Is there any way to make this work with the GPU and the NIC in PCI1 and PCI3?

I can put the NIC in PCI5 but it only operates at 5Gb/sec because it becomes an X2 slot since I have a serial card in PCI2. I guess another question that could possibly help is if anyone knows how to configure a USB to serial adapter to present as ttyUSB0? If I could get that to work I could ditch the serial card and possibly get PCI5 back up to a speed which would support 10Gb/sec.

Thanks for any help, Derek

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dealy663 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 02 Jul 2023 Location: Redondo Beach Status: Offline Points: 70	Post Options Post Reply Quote dealy663 Report Post Thanks(0) Quote Reply Topic: B550 Taichi ACS enable possible£ Posted: 02 Jul 2023 at 9:49pm
	Hi I have two video cards and a 10Gbe NIC in my system. I have been struggling to get it to work right when using PCI passthrough for one of the GPUs. The problem stems from the fact that the system assigns both the 10Gbe NIC and the main GPU to the same IOMMU group. I can't pass the NIC through to the VM, but that is what the system needs since you can't assign only some of the members of the IOMMU group. It sounds like the normal way to handle this is by enabling ACS on the mono. But I don't see anyway to do that in my BIOS. I'm already up to version 2.62. Is there any way to make this work with the GPU and the NIC in PCI1 and PCI3? I can put the NIC in PCI5 but it only operates at 5Gb/sec because it becomes an X2 slot since I have a serial card in PCI2. I guess another question that could possibly help is if anyone knows how to configure a USB to serial adapter to present as ttyUSB0? If I could get that to work I could ditch the serial card and possibly get PCI5 back up to a speed which would support 10Gb/sec. Thanks for any help, Derek

eccential Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 10 Oct 2022 Location: Nevada Status: Offline Points: 5510	Post Options Post Reply Quote eccential Report Post Thanks(0) Quote Reply Posted: 02 Jul 2023 at 10:58pm
	I don't have that motherboard, but I imagine the BIOS is similar. Advanced -> PCI Configuration -> SR-IOV Support (I assume you already have this enabled?) Advanced -> AMD CBS -> NBIO Common Options -> Lots of fun stuff in here. IOMMU, ACS, PCIe ARI Support, PCIe ARI Enumeration, Enable AER Capability, SRIS. Apparently, ACS and AER are tied together, so you have to enable AER for ACS to work.

dealy663 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 02 Jul 2023 Location: Redondo Beach Status: Offline Points: 70	Post Options Post Reply Quote dealy663 Report Post Thanks(0) Quote Reply Posted: 03 Jul 2023 at 12:46am
	Woot! Well, why did it take so long for me to find that tidbit of information? You would think that they would have just had ACS greyed out when it wasn't available, instead of just hidden altogether until the AER was enabled. But of course there was no mention anywhere that AER was the secret. I think this will enable me to do what I originally was after since now all of those PCI devices are spread across several more IOMMU groups. Thanks for the pointer!