kern/55856: uaudio gets device timeout on C-Media USB sound device

[buhrow%nfbcal.org@localhost]

>Number:         55856
>Category:       kern
>Synopsis:       uaudio(4) device timeout on C-Media USB sound  card
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Dec 11 00:50:00 +0000 2020
>Originator:     Brian Buhrow
>Release:        NetBSD 9.1_stable
>Organization:
	NFB of California
>Environment:
	
	
System: 
NetBSD mirkwood.nfbcal.org 9.1_STABLE NetBSD 9.1_STABLE (MIRKWOOD) #12: Thu Dec 10 16:02:52 PST 2020  buhrow%loth-9.nfbcal.org@localhost:/usr/local/netbsd/src-90/sys/arch/amd64/compile/MIRKWOOD amd64
Architecture: x86_64
Machine: amd64
>Description:
	
When trying to play audio through the uaudio device, I get the following
error messages from the kernel.  In addition, the audio does not play and
the player, mpg123 in this case, gets write failures.
Kernel messages look like:

[   425.807534] uaudio0 at uhub1 port 1 configuration 1 interface 0
[   425.807534] uaudio0: C-Media Electronics Inc. (0xd8c) C-Media USB Headphone Set (0x0c), rev 1.10/1.00, addr 3
[   425.807534] uaudio0: audio rev 1.00
[   425.807534] audio1 at uaudio0: playback, capture, full duplex, independent
[   425.807534] audio1: slinear_le:16 2ch 48000Hz, blk 11520 bytes (60ms) for playback
[   425.807534] audio1: slinear_le:16 1ch 48000Hz, blk 5760 bytes (60ms) for recording
[   425.807534] spkr2 at audio1: PC Speaker (synthesized)
[   425.807534] wsbell2 at spkr2 mux 1
[   425.807534] uhidev0 at uhub1 port 1 configuration 1 interface 3
[   425.807534] uhidev0: C-Media Electronics Inc. (0xd8c) C-Media USB Headphone Set (0x0c), rev 1.10/1.00, addr 3, iclass 3/0
[   425.807534] uhid0 at uhidev0: input=4, output=4, feature=0
[   637.647534] audio1: trigger_output failed with 5
[   640.657534] audio1: device timeout
[   643.657534] audio1: device timeout

>How-To-Repeat:
	Plug in one of these USB devices to a NetBSD-9.1 system and try to
send audio, using mpg123, mplayer, or something, through its association
audio device.
It's worth noting this device works perfectly under NetBSD-3, NetBSD-4,
NetBSD-5 and FreeBSD-12.  So, I think this is probably a regression from
the new audio subsystem that went in for NetBSD-9.x.  I've tried plugging
into different  USB ports on the system, with the same result.

	
>Fix:
	

>Unformatted: