Supermicro X9 + HBA = No Network Interface found

[[Nobody]]

I installed Proxmox 7.4 on my Supermicro X9SRI-F (8.1 resulted in "frequency out of range" on the video output). and everything worked fine and upgraded to 8.1. Then I took my HBA (Dell Perc H310 flashed to IT mode) from another server and placed it in the lower-most (PCI-E 3.0 8x) slot. Now my NICs aren't detected anymore, except IPMI. Linux can't see them (when I try to install proxmox again it tells me "no network interface found"); they even don't show up under lspci. When I remove the HBA then it works fine again.

Any ideas what the problem is?

 

[[Nobody]]

Something I found out:

lsipci -v gives me this:

04:00.0 Serial Attached SCSI controller: Broadcom / LSI SAS2008 PCI-Express Fusion
        DeviceName: Onboard Intel i350 Ethernet

I think there is something wrong with the IOMMU Group.

 

[[Nobody]]

I found a solution: acitvate Bifurcation on this slot to 8x8.