[SOLVED] ASUS NVMe PCIe card not showing drives

Hardware Hub Motherboards
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In TrueNAS 13, the drives for the ASUS Hyper M.2 x16 gen 4 card aren’t showing up or the drives are not.

My motherboard is the ASRock Rack ROMED8-2T.

I’m not fluent enough in FreeBSD to figure it out. I did lsusb and got back a ton of devices. Using grep, I narrowed it down, but I’m not sure what to look for.

Do I need to enable the Option ROM for this PCIe port?

The 4 drives are all Intel Optane 905p connected through the NVMe to U.2 (looks like SAS) connector that came with them.

I have 8 of these drives, 2 of them are hooked into the motherboard’s NVMe ports. Those work fine. The 4 on this ASUS card aren’t showing up though.

What can I do to troubleshoot or what might be the issue?

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Did you configure bifurcation in BIOS?
Advanced → Chipset → PCIE Link Width should be x4x4x4x4

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Just fixed it thanks! Does that need to happen for a Windows Ryzen PC as well or is this just a quirk of Epyc server hardware?

After making the change, do I need a reboot? Which reboot option should I choose if I do?

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Huh, I thought is bifurcation is not switched on, it would just show the first drive in the socket, not the rest?

And that it would need lspci To see the card.

Good info though, thanks

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Confirmed, it’s working after enabling 4x4x4x4x bifurcation. Never seen this on my high-end gamer motherboards, but maybe I just passed it by.

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Sorry about the delayed response, been an incredibly busy end of year for me.

It’s required for any system to use a card like this, though it may be called something else on gaming boards — ASUS likes to refer to it as “PCIe RAID”.

What’s going on behind the scenes is that the Hyper card is physically routing each block of 4 PCIe lanes (from the x16 slot) to a separate device (M.2 slot), with some control signal duplication. It doesn’t have any real intelligence, it’s “just” rewiring the PCIe slot, so the other half of this equation is that the system’s PCIe controller needs to explicitly support this rewiring. That BIOS setting configures the controller to treat the physically wired x16 slot as four separate x4 slots.

This is PCIe bifurcation, and currently AMD has more support for this than intel, though it’s also up to the motherboard vendor to enable it. It is more common in the server space.

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