H115i cooler for Threadripper not detected on USB bus with MSI X399 Carbon motherboar

I am using a Threadripper 1950X CPU on a MSI X399 Carbon motherboard (which I wouldn't recommend -- one of the RAM banks appears dead no matter how much I move sticks around.)

I am cooling with a Corsair H115i.

The H115i is connected to one of the two available motherboard USB-2 headers. The other header is connected to the RM850i power supply I also use.

When I run "lsusb" I find the power supply, but I do not find the cooler on the USB bus:

jwatte@ripper:/usr/local/src/OpenCorsairLink$ lsusb
Bus 008 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 007 Device 003: ID 258a:1007   # no-name mouse
Bus 007 Device 002: ID 1a2c:2e43 China Resource Semico Co., Ltd  # no-name keyboard
Bus 007 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 045e:0800 Microsoft Corp.  # wireless keyboard
Bus 001 Device 002: ID 1b1c:1c0c Corsair  # RM850i power supply
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Unplugging and re-plugging the cooler mini-USB cable while running "usbadm monitor" does not show any changes in detection on the USB bus.

What can be causing this?

I swapped the two headers on the motherboard between PSU and pump, and then both devices showed up. I'm willing to believe I had somehow not seated the pump USB cable correctly, and this fixed it.

jwatte@ripper:/usr/local/src/OpenCorsairLink$ sudo ./OpenCorsairLink.elf --device 0
Dev=0, CorsairLink Device Found: H115i!
Dev=1, CorsairLink Device Found: RM850i!

Vendor: Corsair
Product: H115i
Firmware: 2.8.0.0
Temperature 0: 31.10
Fan Speed 0: 840
Pump Speed: 2910
jwatte@ripper:/usr/local/src/OpenCorsairLink$ sudo ./OpenCorsairLink.elf --device 1
Dev=0, CorsairLink Device Found: H115i!
Dev=1, CorsairLink Device Found: RM850i!

Vendor: CORSAIR
Product: RM850i
Firmware: NA
Temperature 0: 44.50 C
Temperature 1: 36.50 C
Powered: 242648 (2d.  19h)
Uptime: 1448 (0d.  0h)
Supply Voltage: 115.00
Total Watts: 156.00
Output 12v:
Voltage 12.06
Amps 11.00
Watts 132.00
Output 5v:
Voltage  5.06
Amps  5.00
Watts 25.00
Output 3.3v:
Voltage  3.34
Amps  1.12
Watts  4.00
jwatte@ripper:/usr/local/src/OpenCorsairLink$