Re: [PATCH v3 2/2] coreaudio: Initialize the buffer for device change

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Wednesday, January 15, 2025 1:06:56 PM CET Akihiko Odaki wrote:
> Reallocate buffers when the active device change as the required buffer
> size may differ.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  audio/audio_int.h |  2 ++
>  audio/audio.c     | 24 ++++++++++++++++++------
>  audio/coreaudio.m |  1 +
>  3 files changed, 21 insertions(+), 6 deletions(-)
> 
> diff --git a/audio/audio_int.h b/audio/audio_int.h
> index 2d079d00a259..9ba4a144d571 100644
> --- a/audio/audio_int.h
> +++ b/audio/audio_int.h
> @@ -187,9 +187,11 @@ struct audio_pcm_ops {
>      void   (*volume_in)(HWVoiceIn *hw, Volume *vol);
>  };
>  
> +void audio_generic_initialize_buffer_in(HWVoiceIn *hw);
>  void audio_generic_run_buffer_in(HWVoiceIn *hw);
>  void *audio_generic_get_buffer_in(HWVoiceIn *hw, size_t *size);
>  void audio_generic_put_buffer_in(HWVoiceIn *hw, void *buf, size_t size);
> +void audio_generic_initialize_buffer_out(HWVoiceOut *hw);
>  void audio_generic_run_buffer_out(HWVoiceOut *hw);
>  size_t audio_generic_buffer_get_free(HWVoiceOut *hw);
>  void *audio_generic_get_buffer_out(HWVoiceOut *hw, size_t *size);
> diff --git a/audio/audio.c b/audio/audio.c
> index 87b4e9b6f2f3..17c6bbd0ae9e 100644
> --- a/audio/audio.c
> +++ b/audio/audio.c
> @@ -1407,12 +1407,18 @@ void audio_run(AudioState *s, const char *msg)
>  #endif
>  }
>  
> +void audio_generic_initialize_buffer_in(HWVoiceIn *hw)
> +{
> +    g_free(hw->buf_emul);
> +    hw->size_emul = hw->samples * hw->info.bytes_per_frame;
> +    hw->buf_emul = g_malloc(hw->size_emul);
> +    hw->pos_emul = hw->pending_emul = 0;
> +}
> +

Better something like "reinit" in the name maybe?

>  void audio_generic_run_buffer_in(HWVoiceIn *hw)
>  {
>      if (unlikely(!hw->buf_emul)) {
> -        hw->size_emul = hw->samples * hw->info.bytes_per_frame;
> -        hw->buf_emul = g_malloc(hw->size_emul);
> -        hw->pos_emul = hw->pending_emul = 0;
> +        audio_generic_initialize_buffer_in(hw);
>      }
>  
>      while (hw->pending_emul < hw->size_emul) {
> @@ -1446,6 +1452,14 @@ void audio_generic_put_buffer_in(HWVoiceIn *hw, void *buf, size_t size)
>      hw->pending_emul -= size;
>  }
>  
> +void audio_generic_initialize_buffer_out(HWVoiceOut *hw)
> +{
> +    g_free(hw->buf_emul);
> +    hw->size_emul = hw->samples * hw->info.bytes_per_frame;
> +    hw->buf_emul = g_malloc(hw->size_emul);
> +    hw->pos_emul = hw->pending_emul = 0;
> +}
> +
>  size_t audio_generic_buffer_get_free(HWVoiceOut *hw)
>  {
>      if (hw->buf_emul) {
> @@ -1477,9 +1491,7 @@ void audio_generic_run_buffer_out(HWVoiceOut *hw)
>  void *audio_generic_get_buffer_out(HWVoiceOut *hw, size_t *size)
>  {
>      if (unlikely(!hw->buf_emul)) {
> -        hw->size_emul = hw->samples * hw->info.bytes_per_frame;
> -        hw->buf_emul = g_malloc(hw->size_emul);
> -        hw->pos_emul = hw->pending_emul = 0;
> +        audio_generic_initialize_buffer_out(hw);
>      }
>  
>      *size = MIN(hw->size_emul - hw->pending_emul,
> diff --git a/audio/coreaudio.m b/audio/coreaudio.m
> index b9e1a952ed37..72a6df0f75ee 100644
> --- a/audio/coreaudio.m
> +++ b/audio/coreaudio.m
> @@ -466,6 +466,7 @@ static OSStatus init_out_device(coreaudioVoiceOut *core)
>      core->outputDeviceID = deviceID;
>      core->audioDevicePropertyBufferFrameSize = audioDevicePropertyBufferFrameSize;
>      core->hw.samples = core->bufferCount * core->audioDevicePropertyBufferFrameSize;
> +    audio_generic_initialize_buffer_out(&core->hw);
>      core->ioprocid = ioprocid;

I would have probably separated this change into a separate patch, as changes
above were more or less just refactoring, whereas this one changes behaviour.

And like my comment in the previous patch, I wonder whether that call comes
too late. Keep in mind there are e.g. audio devices where you can't change
certain parameters. So not every error here is a fatal error.

>  
>      return 0;