Post failure with USB 3.2 PCIe card

msie14f502c8

New member
Joined
Feb 23, 2021
Messages
4
Hi,

I tried installing a Sonnet USB3C-2PM-E USB-C 3.2 Gen 2 extension card in my x570 Unify motherboard.

Installing it into PCI_E5 consistently made the BIOS fail with POST code 94 (bus enumeration), while entering a boot-loop when it was connected to PCI_E3.
Explicitly setting the PCIe generation (instead of auto) didn't seem to do much good either.
BIOS is the latest version available (7C35vA8).

I'm not sure if there's something special about this particular card, or if connecting any PCIe with a x2 bus interface (in a x4 form) isn't fully supported by MSI.

Any chance anyone succeeded in using this card or a similar one with this card?

Thanks!
 

eqwebbie_with_PC

Experienced Dummy
Joined
Aug 22, 2020
Messages
507
Hi,
full system specs would be nice.
As far as I have seen, this card is powered by PCIE only. This seems a bit strange, because USB 3 devices often need more power than PCIE can deliver.
What do you plan to connect?
 

msie14f502c8

New member
Joined
Feb 23, 2021
Messages
4
Hi,
full system specs would be nice.
As far as I have seen, this card is powered by PCIE only. This seems a bit strange, because USB 3 devices often need more power than PCIE can deliver.
What do you plan to connect?
In terms of specs, this is a x570 Unify/3950x/64GB-3200MHz/XT 5700 system.

In terms of power consumption, this card can presumably withstand a maximum of 30W in total (without connecting it to the PSU), not including its self power requirements.
While this stretches the limits of the PCIe slot (and in some cases may even exceed it), the plan was to connect it to a powered hub anyway, so that's less of a concern. In any case, this issue happens without any devices connected, so unless the card is toast, it shouldn't draw anything beyond its internal power usage.

Thanks!
 

SeoulFinn

Lover of budaejjigea
SERGEANT
Joined
Sep 26, 2015
Messages
159
As far as I know, PCIe slot can deliver 75w. Should be more than enough.
 

SeoulFinn

Lover of budaejjigea
SERGEANT
Joined
Sep 26, 2015
Messages
159
OT:

If I'm not mistaken of the exact product we are talking about, on the manufacturer's site it says:

"The Allegro™ USB-C PCIe(1) card supports data transfers at up to twice as fast as USB 3.0, and can also deliver 15W of power per port to USB-C bus-powered devices (three times the 4.5W specified in the USB 3.0 spec) "

I know that some can deliver more, but for this card 75w is plenty. /OT
 

darkhawk

Well-known member
Global Moderator
Joined
Nov 20, 2012
Messages
13,290
Well, USB power delivery specification says USB-C delivers up to 100 Watt. This card has 2 connectors, so per specification should be able to deliver 200 Watt. But it gets only 70 Watt max.
Look here: https://en.m.wikipedia.org/wiki/USB#PD
What PSU do you use?
That's USB PD, not USB-C inherently. There's a difference......

USB-C itself isn't designed to handle more than 15W without special hardware built into the cable itself, mostly in order to tell the controller it's connected to that it can handle more than 15W. That's where USB PD comes in.

I don't see a power problem here at all.
Helpful links :
 

darkhawk

Well-known member
Global Moderator
Joined
Nov 20, 2012
Messages
13,290
Hi,

I tried installing a Sonnet USB3C-2PM-E USB-C 3.2 Gen 2 extension card in my x570 Unify motherboard.

Installing it into PCI_E5 consistently made the BIOS fail with POST code 94 (bus enumeration), while entering a boot-loop when it was connected to PCI_E3.
Explicitly setting the PCIe generation (instead of auto) didn't seem to do much good either.
BIOS is the latest version available (7C35vA8).

I'm not sure if there's something special about this particular card, or if connecting any PCIe with a x2 bus interface (in a x4 form) isn't fully supported by MSI.

Any chance anyone succeeded in using this card or a similar one with this card?

Thanks!
Contact MSI directly here : >>How to contact MSI.<<

Most likely it's an issue with the BIOS in some way that can be resolved once they look into it.
 

msie14f502c8

New member
Joined
Feb 23, 2021
Messages
4
Thanks all for the suggestions and inputs.

I believe the power consumption can indeed be a concern since this is a x4 form factor card. IIRC, the 75w limit is for x16, while the specification limits x4 to 25w. In practice this might not be enforced by motherboards though.
I don't know if the card really draws more than 30w, or simply caps it at 25w when both devices are connected (presumably not).
In any case, this should only really happen when devices are connected and withdrawing power at 15w each, which wasn't the case here, so unlikely to be the culprit.

I agree with @darkhawk that this is likely to be a BIOS issue. Unfortunately, since I have to move fast, I can't wait for a BIOS upgrade so just going to replace it with another card, perhaps one which is truly x4, and with a different chipset..
 

darkhawk

Well-known member
Global Moderator
Joined
Nov 20, 2012
Messages
13,290
Yeah, and even then, if it's not posting with ANYTHING connected to it, then it's most likely a bios issue more than anything else.....

I guess the other question is.....why are you trying to add more USB 3.2 ports to the computer? Is there any particular reason?
 

msie14f502c8

New member
Joined
Feb 23, 2021
Messages
4
Yes, this is required for passing through the whole host controller to a VM (for development purposes).

While passing through USB devices to VMs is possible, it's not entirely transparent to the devices since they they're enumerated twice (once by the host OS and once by the guest OS). This can be problematic in some extreme corner cases.

Adding another host controller and passing it as a whole (passing through the PCIe and not USB devices) is the easiest workaround for this.
 
Top