kern/53028: hdaudio default latency too high, mpv spins at 100% CPU playing audio

[coypu%sdf.org@localhost]

>Number:         53028
>Category:       kern
>Synopsis:       hdaudio default latency too high, mpv spins at 100% CPU playing audio
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Feb 14 14:15:00 +0000 2018
>Originator:     coypu
>Release:        NetBSD 8.99.12
>Organization:
>Environment:
NetBSD planets 8.99.12 NetBSD 8.99.12 (GENERIC) #0: Thu Feb  8 00:38:03 IST 2018  fly@planets:/usr/src/sys/arch/amd64/compile/GENERIC amd64

>Description:
playing s32 audio on mpv, it spins the CPU at 100%.

hdaudio0 at pci0 dev 27 function 0: HD Audio Controller
hdaudio0: interrupting at msi0 vec 0
hdafg0 at hdaudio0: vendor 111d product 7605
hdafg0: DAC00 2ch: Speaker [Built-In], HP Out [Jack]
hdafg0: ADC01 2ch: Mic In [Jack]
hdafg0: ADC02 2ch: Mic In [Built-In]
hdafg0: 2ch/2ch 44100Hz 48000Hz 88200Hz 96000Hz 192000Hz PCM16 PCM20 PCM24 AC3
audio0 at hdafg0: full duplex, playback, capture, mmap, independent
hdafg0: Virtual format configured - Format SLINEAR, precision 16, channels 2, frequency 48000
hdafg0: Latency: 128 milliseconds

>How-To-Repeat:

>Fix:
from nat@:

using:
- lowering hw.hdafg0.latency a lot

or,
- mpv --audio-format=s16

fixes the problem.