Acer XC1660G-UW94 Unit fails to POST with known good PCIe NIC or card isn't simply compatible

KarB1NE

Does anyone have this unit working with a PCIe NIC? My goal is to use this unit with pfSense and a known good DELL intel X550-T2 PCIe NIC. However, the unit fails to POST with the card installed. All I get is one long never-ending beep. Unit works fine without the card installed. As it stands now, I guessing either my PCIe slot is bad or the card isn't simply compatible with this unit. Please advise.

[Edited the thread to add issue detail]

StevenGen

https://community.acer.com/en/discussion/674283/acer-xc1660g-uw94-unit-fails-to-post-with-known-good-pcie-nic

The Intel X550-T2 PCIe NIC card is a PCIe v3.0 (8.0 GT/s) and the XC-1660 Video Interface PCI-E x16 Video controller Intel® CML-S CPU or RKL-S CPU, for this card to work you need to install the Intel driver for the "Intel® Ethernet Controller X550", try that and see if this card works.

KarB1NE

Unfortunately I can't get that far as with the card installed, the unit fails to boot (no video and no power on self test) and beeps indefinitely.

billsey

Are you trying to put it into the x1 slot or the x16 slot? It requires x4 at least...

KarB1NE

I'm installing it on the x16 slot. I don't have access to the service manual, can someone identify the beep code please? Next, I'll attempt to disable SMBus on the PCIe Card. I've got kapton tape on the way.

billsey

A long, never ending beep is a memory failure that blocks POST from starting. The PCIe slot doesn't get initialized until after the memory has come up, unless they are doing something on that board that I'm not aware of...

Just waded through the list. They do a pre-memory initialization of the CPU, north bridge and south bridge, then bring the memory up, then finish the initialization of the CPU, north bridge and south bridge before they start to allocate the PCI space. So with the long beep we're not getting into the PCI card itself at all. I wonder if it's pulling the power down enough to cause the memory failure? I had a server dual port GBIC card that acted like that at one point. Putting a different card in instead worked fine. The card itself was bad, but you could sort of tell because it got really hot pretty quickly.

KarB1NE

I've updated the firmware on the PCIe NIC which also updated the EFI Version on the card. Issue still persisted. It was only when I covered pin B5 and B6 on the PCIe card with kapton tape to disable SMBus that the unit POSTed fine. It seems that Acer's implementation is not compatible with any PCIe cards that use SMBus for advanced in-UEFI configuration. SMBus is also the protocol used for RAM Serial Presence Detect (SPD), which could explain the memory error beep code. Granted my use case may not be common, I hope that it can also be fixed via a BIOS update.

billsey

Interesting! Yes, most consumer level machines don't have support for server level hardware and I'd bet that card is trying to do something server specific on the SMBus. The SMBus handling is in the chipset, so likely the B560 Chipset is where the issue lies.