[alsa-devel] [PATCH (alsa-lib)] chmap: Always succeed setting the map to what it already is

[Takashi Iwai]

At Wed,  5 Jun 2013 16:52:10 +0200,
David Henningsson wrote:
> 
> If we try to set the channel map to what it already is, this should
> always succeed. E g, speaker-test can do this sometimes.
> 
> Signed-off-by: David Henningsson <david.henningsson at canonical.com>

Thanks, applied.


Takashi

> ---
>  src/pcm/pcm.c |   11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c
> index 7ec1f0e..ca4d416 100644
> --- a/src/pcm/pcm.c
> +++ b/src/pcm/pcm.c
> @@ -7361,6 +7361,13 @@ OBSOLETE1(snd_pcm_sw_params_get_silence_size, ALSA_0.9, ALSA_0.9.0rc4);
>  
>  #endif /* DOC_HIDDEN */
>  
> +static int chmap_equal(const snd_pcm_chmap_t *a, const snd_pcm_chmap_t *b)
> +{
> +	if (a->channels != b->channels)
> +		return 0;
> +	return !memcmp(a->pos, b->pos, a->channels * sizeof(a->pos[0]));
> +}
> +
>  /**
>   * \!brief Query the available channel maps
>   * \param pcm PCM handle to query
> @@ -7415,6 +7422,10 @@ snd_pcm_chmap_t *snd_pcm_get_chmap(snd_pcm_t *pcm)
>   */
>  int snd_pcm_set_chmap(snd_pcm_t *pcm, const snd_pcm_chmap_t *map)
>  {
> +	const snd_pcm_chmap_t *oldmap = snd_pcm_get_chmap(pcm);
> +	if (oldmap && chmap_equal(oldmap, map))
> +		return 0;
> +
>  	if (!pcm->ops->set_chmap)
>  		return -ENXIO;
>  	return pcm->ops->set_chmap(pcm, map);
> -- 
> 1.7.9.5
>