On Tue, 04 Apr 2017 08:30:18 +0200,
sutar.mounesh@xxxxxxxxx wrote:
>
> From: Timo Wischer <twischer@xxxxxxxxxxxxxx>
>
> Distorted sound is heard if the capture device of an ioplug plugin is used,
> which is accessed through any ALSA plugin (like copy, linear, ...) via MMAP access.
> E.g. aplay -> loop -> copy -> arecord -M -> aplay -> hw:0
> As mentioned in the ALSA API (see pcm/pcm.c:942):
> The function #snd_pcm_avail_update() have to be called
> before any mmap begin+commit operation.
>
> Signed-off-by: Timo Wischer <twischer@xxxxxxxxxxxxxx>
> Signed-off-by: Mounesh Sutar <sutar.mounesh@xxxxxxxxx>
Applied this one, too. Thanks.
Takashi
>
> diff --git a/src/pcm/pcm_plugin.c b/src/pcm/pcm_plugin.c
> index aaea2ab..ec57f6e 100644
> --- a/src/pcm/pcm_plugin.c
> +++ b/src/pcm/pcm_plugin.c
> @@ -490,7 +490,14 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
> snd_pcm_uframes_t slave_offset;
> snd_pcm_uframes_t slave_frames = ULONG_MAX;
> snd_pcm_sframes_t result;
> -
> + /* As mentioned in the ALSA API (see pcm/pcm.c:942):
> + * The function #snd_pcm_avail_update()
> + * have to be called before any mmap begin+commit operation.
> + * Otherwise the snd_pcm_areas_copy will not called a second time.
> + * But this is needed, if the ring buffer wrap is reached and
> + * there is more data available.
> + */
> + slave_size = snd_pcm_avail_update(slave);
> result = snd_pcm_mmap_begin(slave, &slave_areas, &slave_offset, &slave_frames);
> if (result < 0) {
> err = result;
> --
> 2.7.4
>
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