Re: [Qemu-devel] [PATCH 02/11] audio: basic support for multi backend audio

[Dr. David Alan Gilbert]

* Zoltán Kővágó (address@hidden) wrote:
> On 2019-07-10 06:06, Markus Armbruster wrote:
> > "Kővágó, Zoltán" <address@hidden> writes:
> > 
> >> Audio functions no longer access glob_audio_state, instead they get an
> >> AudioState as a parameter.  This is required in order to support
> >> multiple backends.
> >>
> >> glob_audio_state is also gone, and replaced with a tailq so we can store
> >> more than one states.
> >>
> >> Signed-off-by: Kővágó, Zoltán <address@hidden>
> >> ---
> > [...]
> >> diff --git a/hmp-commands.hx b/hmp-commands.hx
> >> index bfa5681dd2..23196da3fe 100644
> >> --- a/hmp-commands.hx
> >> +++ b/hmp-commands.hx
> >> @@ -819,16 +819,17 @@ ETEXI
> >>  
> >>      {
> >>          .name       = "wavcapture",
> >> -        .args_type  = "path:F,freq:i?,bits:i?,nchannels:i?",
> >> -        .params     = "path [frequency [bits [channels]]]",
> >> +        .args_type  = "path:F,freq:i?,bits:i?,nchannels:i?,audiodev:s?",
> >> +        .params     = "path [frequency [bits [channels [audiodev]]]]",
> >>          .help       = "capture audio to a wave file (default 
> >> frequency=44100 bits=16 channels=2)",
> >>          .cmd        = hmp_wavcapture,
> >>      },
> >>  STEXI
> >> -@item wavcapture @var{filename} [@var{frequency} [@var{bits} 
> >> [@var{channels}]]]
> >> +@item wavcapture @var{filename} [@var{frequency} [@var{bits} 
> >> [@var{channels} [@var{audiodev}]]]]
> >>  @findex wavcapture
> >> -Capture audio into @var{filename}. Using sample rate @var{frequency}
> >> -bits per sample @var{bits} and number of channels @var{channels}.
> >> +Capture audio into @var{filename} from @var{audiodev}. Using sample rate
> >> +@var{frequency} bits per sample @var{bits} and number of channels
> >> +@var{channels}.
> >>  
> >>  Defaults:
> >>  @itemize @minus
> >    @item Sample rate = 44100 Hz - CD quality
> >    @item Bits = 16
> >    @item Number of channels = 2 - Stereo
> >    @end itemize
> >    ETEXI
> > 
> > Defaults for the other optional arguments are listed here.  Why not for
> > @audiodev?
> 
> There's no default listed because there's no default when you use the
> -audiodev options, since there's no good default.  When you don't use
> -audiodev, it'll use the implicitly created audiodev which doesn't have
> a name, so it can't be specified.  But I agree that this situation
> should be documented somehow.
> 
> > 
> >> diff --git a/qemu-options.hx b/qemu-options.hx
> >> index 9621e934c0..0111055aa4 100644
> >> --- a/qemu-options.hx
> >> +++ b/qemu-options.hx
> >> @@ -1978,6 +1978,11 @@ can help the device and guest to keep up and not 
> >> lose events in case
> >>  events are arriving in bulk.  Possible causes for the latter are flaky
> >>  network connections, or scripts for automated testing.
> >>  
> >> +@item audiodev=@var{audiodev}
> >> +
> >> +Use the specified @var{audiodev} when the VNC client requests audio
> >> +transmission.
> >> +
> > 
> > What's the default?
> 
> It's the same story as wav_capture.

OK, so I think you're saying the default behaviour doesn't change.
Add a comment to document that, and that seems OK.

Dave

> Regards,
> Zoltan
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK