Supermicro motherboard 13th gen with AMI bios - delay PCIe bus enumeration

[sam55todd]

Hello,
Is there a way to increase delay PCIe devices enumeration step on Supermicro motherboards in BIOS initialization? ( I've X13DEI )
(A.K.A. step "94 PCI Bus Enumeration" )

I've a device (USB card) which has firmware most likely needing extra 5 seconds before reporting ready status back to a system (There are some forums suggesting this card/chip might need more time for boot).
As a result in operating system PCIe device is not detected (card works just fine on other systems, e.g. Dell PC).
But sometimes (some boots) card does work just fine - therefore I'm getting around 60% failure rate for this card (never once it was successfully detected, only boot is a problem, visual check shown no damaged components, including electrolytic capacitors, although haven't checked voltages or capacitor' ability to hold charge electrically)

Also tried to switch in BIOS PCIe OPROM from EFI to Legacy, same result, enabled/disabled bus mastering, modified supported payload size from Auto, forced PCIe into Gen2 as per card specification, all the same)
Nothing to do with bifurcation (if detects then shows only one PCIe lane device {first one}, probably PCIe switch on card is affecting this)

Card (have two actually, both exhibit same behavior) is PCIe x4 USB3 controller from Startech model PEXUSB3S44V, topology: one PCIe bridge (Pericom Semiconductor / Diodes Incorporated or maybe ASMedia with x4 channels) then x4 NEC (Renesas, one per each pcie lane) uPD720202 chips (each has individual firmware ROM). Firmware (-s, on both: BMC/IPMI/BIOS and PCIe card) was updated to latest version - same result.
Operating system: Windows11 Pro (haven't tried Linux or other versions) with either native USB drivers or the ones provided by Startech (Renesas drivers)

Thank you.

 

[Charles@solace]

We have the same problem. We have opened a Supermicro case and encourage anyone else who has this issue to do the same.

There is some chance we can fix this in the Kernel - but that will be a lot of work. Much nicer if Supermicro provided an option to delay enumeration by some number of seconds - say 1 to 10. I doubt if we are the only two users that will have this issue.

 

[Charles@solace]

To clarify, our issue is with the loading of a FPGA - fairly large FPGA takes time to load config data.

 

[mattventura]

Does the switch chip on the card show up in your pcie topology even if the card itself appears to not be working? Have you tried a pcie rescan after boot?