Re: [Qemu-devel] [PATCH 1/2] Introduce AUD_set_volume

["andrzej zaborowski" <balrogg@gmail.com>]

On 02/05/2008, Jan Kiszka <jan.kiszka@web.de> wrote:
> andrzej zaborowski wrote:
>  > The user still needs to disable NOVOL if they really want volume control.
>
> What is the "user" here? wm8750? musicpal? I just hope it is not the
>  real user... :)

Whoever builds qemu.  You don't want it enabled by default and globally.

>
>  [ QEMU audio setup is already weird enough: I recently tried to get ALSA
>  running to overcome outdated OSS - well, tricky. Needs fixing. ]

Yup, I had alsa running but normally (for example now) I just run qemu
through "aoss".

>
>  > diff --git a/audio/audio.c b/audio/audio.c
>  > index 9e7fe80..1231ec5 100644
>  > --- a/audio/audio.c
>  > +++ b/audio/audio.c
>  > @@ -1955,3 +1955,21 @@ void AUD_del_capture (CaptureVoiceOut *cap,
>  > void *cb_opaque)
>  >          }
>  >      }
>  >  }
>  > +
>  > +void AUD_set_volume_out (SWVoiceOut *sw, int mute, uint8_t lvol, uint8_t rvol)
>  > +{
>  > +    if (sw) {
>  > +        sw->vol.mute = mute;
>  > +        sw->vol.l = nominal_volume.l * lvol / 255;
>  > +        sw->vol.r = nominal_volume.r * rvol / 255;

Oops, it may be wrong indeed because it might overflow on machines
with sizeof(int) >= sizeof(int64_t) and no FLOAT_MIXENG.  I first
wrote (nominal_volume.l / 255) * lvol and then immediately changed it,
but that was better.

Regards
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