kern/52098: audio replays buffers under load

[dholland%eecs.harvard.edu@localhost]

>Number:         52098
>Category:       kern
>Synopsis:       audio replays buffers under load
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Mar 21 07:45:00 +0000 2017
>Originator:     David A. Holland
>Release:        NetBSD 7.99.65 (20170309)
>Organization:
>Environment:
System: NetBSD macaran 7.99.65 NetBSD 7.99.65 (MACARAN) #41: Thu Mar 9 19:33:59 EST 2017 dholland@macaran:/usr/src/sys/arch/amd64/compile/MACARAN amd64
Architecture: x86_64
Machine: amd64
>Description:

With a kernel from March 9th (which I believe has most or all of the
main round of audio fixes) I'm getting skipping under load (it was
running ogg123 while compiling lang/coq) but the skipping comes in the
form of repeating a buffer rather than glitching or hiccuping. This is
not necessarily fatal but to me at least it's a lot more distracting
than a regular glitch.

also, a build that isn't actively swapping to death oughtn't skip.

audio hw is:

hdaudio0 at pci0 dev 27 function 0: HD Audio Controller
hdaudio0: interrupting at msi1 vec 0
hdafg1 at hdaudio0: vendor 10ec product 0662
hdafg1: DAC00 2ch: Speaker [Jack], HP Out [Jack]
hdafg1: DIG01 2ch: SPDIF Out [Jack]
hdafg1: ADC02 2ch: Line In [Jack], Mic In [Jack]
hdafg1: 2ch/2ch 44100Hz 48000Hz 96000Hz PCM16 PCM20 PCM24 AC3
audio0 at hdafg1: full duplex, playback, capture, mmap, independent
hdafg1: Virtual format configured - Format SLINEAR, precision 16, channels 2, frequency 48000

>How-To-Repeat:

>Fix:

maybe the mixer thread needs its priority jacked up?