On Fri, Sep 23, 2022 at 10:51 PM Volker Rümelin <vr_q...@t-online.de> wrote:
> Change the buffer_get_free pcm_ops function to report the free
> ALSA playback buffer. The generic buffer becomes a temporary
> buffer and is empty after a call to audio_run_out().
>
> Signed-off-by: Volker Rümelin <vr_q...@t-online.de>
>
lgtm
Acked-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> audio/alsaaudio.c | 38 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/audio/alsaaudio.c b/audio/alsaaudio.c
> index 4a61378cd7..7a2a94cd42 100644
> --- a/audio/alsaaudio.c
> +++ b/audio/alsaaudio.c
> @@ -602,6 +602,42 @@ static int alsa_open(bool in, struct alsa_params_req
> *req,
> return -1;
> }
>
> +static size_t alsa_buffer_get_free(HWVoiceOut *hw)
> +{
> + ALSAVoiceOut *alsa = (ALSAVoiceOut *)hw;
> + snd_pcm_sframes_t avail;
> + size_t alsa_free, generic_free, generic_in_use;
> +
> + avail = snd_pcm_avail_update(alsa->handle);
> + if (avail < 0) {
> + if (avail == -EPIPE) {
> + if (!alsa_recover(alsa->handle)) {
> + avail = snd_pcm_avail_update(alsa->handle);
> + }
> + }
> + if (avail < 0) {
> + alsa_logerr(avail,
> + "Could not obtain number of available frames\n");
> + avail = 0;
> + }
> + }
> +
> + alsa_free = avail * hw->info.bytes_per_frame;
> + generic_free = audio_generic_buffer_get_free(hw);
> + generic_in_use = hw->samples * hw->info.bytes_per_frame -
> generic_free;
> + if (generic_in_use) {
> + /*
> + * This code can only be reached in the unlikely case that
> + * snd_pcm_avail_update() returned a larger number of frames
> + * than snd_pcm_writei() could write. Make sure that all
> + * remaining bytes in the generic buffer can be written.
> + */
> + alsa_free = alsa_free > generic_in_use ? alsa_free -
> generic_in_use : 0;
> + }
> +
> + return alsa_free;
> +}
> +
> static size_t alsa_write(HWVoiceOut *hw, void *buf, size_t len)
> {
> ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
> @@ -916,7 +952,7 @@ static struct audio_pcm_ops alsa_pcm_ops = {
> .init_out = alsa_init_out,
> .fini_out = alsa_fini_out,
> .write = alsa_write,
> - .buffer_get_free = audio_generic_buffer_get_free,
> + .buffer_get_free = alsa_buffer_get_free,
> .run_buffer_out = audio_generic_run_buffer_out,
> .enable_out = alsa_enable_out,
>
> --
> 2.35.3
>
>
>
--
Marc-André Lureau
