kern/52540: auich: The volume is maximum? on initial audio playback

[isaki%pastel-flower.jp@localhost]

>Number:         52540
>Category:       kern
>Synopsis:       auich: The volume is maximum? on initial audio playback
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Sep 12 14:20:00 +0000 2017
>Originator:     Tetsuya Isaki
>Release:        NetBSD 8.0_BETA i386
>Organization:
none
>Environment:
NetBSD 8.0_BETA i386
>Description:
On initial audio playback after reboot, the volume sounds like
maximum(?) even if mixerctl shows outputs.master=127,127.

This is the related part of dmesg.  It's VirtualBox 5.1 on Windows.
auich0 at pci0 dev 5 function 0: i82801AA (ICH) AC-97 Audio
auich0: interrupting at irq 11
auich0: ac97: SigmaTel STAC9700 codec; no 3D stereo
auich0: ac97: ext id 0x809<AC97_23,VRM,VRA>
auich0: measured ac97 link rate at 46381 Hz, will use 48000 Hz
audio0 at auich0: full duplex, playback, capture, mmap, independent
auich0: Virtual format configured - Format SLINEAR, precision 16, channels 2, frequency 48000

It also happens on -current (8.99.2).

I don't have any other audio environment to be able to confirm this
problem.  Therefore I don't know whether the cause is audio(4) or
auich(4).
>How-To-Repeat:
1. reboot and login

2. mixerctl parameters have never been changed since reboot.
   And the initial master volume shows 127.

  % ls /etc/mixerctl.conf
  ls: /etc/mixerctl.conf: No such file or directory
  % mixerctl outputs.master
  outputs.master=127,127

3. On initial audio playback, the volume sounds like maximum.

  % audioplay music.wav

4. But next playback, the volume is small (like 127).

  % audioplay music.wav

5. Of course, when I specify outputs.master explicitly, the volume
   changes correctly (maybe).

 5a.
  % mixerctl -w outputs.master=255
  % audioplay music.wav
 5b.
  % mixerctl -w outputs.master=127
  % audioplay music.wav

   The volume of step 3 sounds the same as step 5a,
   the volume of step 4 sounds the same as step 5b.
>Fix:
N/A