Based on the output, it looks like it is detected by the OS as a USB 3.0 port. This is likely a software issue. You can boot to our support live image to see if the issue persists in another OS.
Dell EMC, Enterprise Engineer
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After much ado, it appears to *not* be the operating system.
Here are some things that did not work:
kernel upgrade + reboot
But what did work was to completely shut down the machine, disconnect
the power, wait a bit, plug it back in and then bring it back up.
After that, the USB3 port on the R530 recognized USB3 disks again.