TL; DR: After a few weeks of deliberation, AMD resolved the intermittent USB connectivity issue reported by many users. An update of AGESA containing the fix will be sent to motherboard manufacturers next week, and it will be up to them thereafter. AMD estimates that the first beta BIOS with the fix will be available in early April.
Reports of sudden USB disconnections and poor signal quality on AMD X570 and B550 motherboards started to become commonplace on Reddit late last year. Three weeks ago, AMD finally recognized the problem and started collecting information from the afflicted. The severity of the problem has been shown to fluctuate randomly, but the likelihood of its occurrence has been correlated with stressful hardware like new GPUs and VR headsets.
AMD did not state what the problem was, unfortunately, but one Redditor suggests that the cause may be a “time issue trying to synchronize USB signaling with the fastest PCIe 4.0 symbol rates”, while another thinks it may be caused by “a controller restart triggered due to many uncorrectable PCIe errors.”
Given that the Redditors have found a workaround good enough for AMD to recommend, their comments should not be dismissed quickly.
Updated AGESA coming for r / Amd intermittent USB connectivity
If you already had the problem, put a reminder on your calendar for the next month to check for an updated BIOS from the motherboard manufacturer.