kern/56574: uaudio at ehci (not xhci) only outputs rapid gunfire noises in 9.99.93

[nia%pkgsrc.org@localhost]

>Number:         56574
>Category:       kern
>Synopsis:       uaudio at ehci (not xhci) only outputs rapid gunfire noises in 9.99.93
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Dec 24 19:30:01 +0000 2021
>Originator:     nia
>Release:        current
>Organization:
The NetBSD Foundation
>Environment:
NetBSD amnesia 9.99.93 NetBSD 9.99.93 (GENERIC) #26: Fri Dec 24 15:39:11 CET 2021  nia@amnesia:/home/nia/obj/sys/arch/amd64/compile/GENERIC amd6
>Description:
A recent regression causes uaudio at ehci to only output rapid gunfire
noises instead of sweet tunes. All of my USB audio devices behave
identically in this regard.

I suspect this is related to recent ehci changes in current since
the problems can't be observed with xhci.
>How-To-Repeat:
Set ECHI mode in BIOS and $ audiocfg test 1

>Fix:
Use xhci