[alsa-devel] [PATCH] pcm_dshare: Do not discard slave reported delay in status result.

[Takashi Iwai]

On Thu, 17 Nov 2016 09:20:16 +0100,
Alan Young wrote:
> 
> snd_pcm_dshare_status() gets the underlying status from the slave PCM.
> This may contain a delay value that includes elements such as codec and
> other transfer delays. Use this as the base for the returned delay
> value, adjusted for any frames buffered locally (within the dshare
> plugin).
> 
> Note: snd_pcm_dshare_delay() is not updated.

Thanks for the patch, but it doesn't look like a proper patch to be
applied to the latest git tree.  I guess you created a patch on top of
the modified tree.

Please rebase and resubmit.

Also, don't forget to add your sign-off.  We prefer having it in
alsa-lib code like the kernel code (although it's not strictly
needed).


Takashi


> ---
>  src/pcm/pcm_dshare.c | 45 ++++++++++++++++++++++++++++-----------------
>  1 file changed, 28 insertions(+), 17 deletions(-)
> 
> diff --git a/src/pcm/pcm_dshare.c b/src/pcm/pcm_dshare.c
> index c5b3178..9b478a7 100644
> --- a/src/pcm/pcm_dshare.c
> +++ b/src/pcm/pcm_dshare.c
> @@ -157,23 +157,14 @@ static void snd_pcm_dshare_sync_area(snd_pcm_t *pcm)
>  /*
>   *  synchronize hardware pointer (hw_ptr) with ours
>   */
> -static int snd_pcm_dshare_sync_ptr(snd_pcm_t *pcm)
> +static int snd_pcm_dshare_sync_ptr0(snd_pcm_t *pcm, snd_pcm_uframes_t slave_hw_ptr)
>  {
>  	snd_pcm_direct_t *dshare = pcm->private_data;
> -	snd_pcm_uframes_t slave_hw_ptr, old_slave_hw_ptr, avail;
> +	snd_pcm_uframes_t old_slave_hw_ptr, avail;
>  	snd_pcm_sframes_t diff;
>  	
> -	switch (snd_pcm_state(dshare->spcm)) {
> -	case SND_PCM_STATE_DISCONNECTED:
> -		dshare->state = SNDRV_PCM_STATE_DISCONNECTED;
> -		return -ENODEV;
> -	default:
> -		break;
> -	}
> -	if (dshare->slowptr)
> -		snd_pcm_hwsync(dshare->spcm);
>  	old_slave_hw_ptr = dshare->slave_hw_ptr;
> -	slave_hw_ptr = dshare->slave_hw_ptr = *dshare->spcm->hw.ptr;
> +	dshare->slave_hw_ptr = slave_hw_ptr;
>  	diff = slave_hw_ptr - old_slave_hw_ptr;
>  	if (diff == 0)		/* fast path */
>  		return 0;
> @@ -207,6 +198,24 @@ static int snd_pcm_dshare_sync_ptr(snd_pcm_t *pcm)
>  	return 0;
>  }
>  +static int snd_pcm_dshare_sync_ptr(snd_pcm_t *pcm)
> +{
> +	snd_pcm_direct_t *dshare = pcm->private_data;
> +
> +	switch (snd_pcm_state(dshare->spcm)) {
> +	case SND_PCM_STATE_DISCONNECTED:
> +		dshare->state = SNDRV_PCM_STATE_DISCONNECTED;
> +		return -ENODEV;
> +	default:
> +		break;
> +	}
> +
> +	if (dshare->slowptr)
> +		snd_pcm_hwsync(dshare->spcm);
> +
> +	return snd_pcm_dshare_sync_ptr0(pcm, *dshare->spcm->hw.ptr);
> +}
> +
>  /*
>   *  plugin implementation
>   */
> @@ -215,22 +224,24 @@ static int snd_pcm_dshare_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
>  {
>  	snd_pcm_direct_t *dshare = pcm->private_data;
>  +	memset(status, 0, sizeof(*status));
> +	snd_pcm_status(dshare->spcm, status);
> +
>  	switch (dshare->state) {
>  	case SNDRV_PCM_STATE_DRAINING:
>  	case SNDRV_PCM_STATE_RUNNING:
> -		snd_pcm_dshare_sync_ptr(pcm);
> +		snd_pcm_dshare_sync_ptr0(pcm, status->hw_ptr);
> +		status->delay += snd_pcm_mmap_playback_delay(pcm)
> +				+ status->avail - dshare->spcm->buffer_size;
>  		break;
>  	default:
>  		break;
>  	}
> -	memset(status, 0, sizeof(*status));
> -	snd_pcm_status(dshare->spcm, status);
> -	status->state = snd_pcm_state(dshare->spcm);
> +
>  	status->trigger_tstamp = dshare->trigger_tstamp;
>  	status->avail = snd_pcm_mmap_playback_avail(pcm);
>  	status->avail_max = status->avail > dshare->avail_max ? status->avail : dshare->avail_max;
>  	dshare->avail_max = 0;
> -	status->delay = snd_pcm_mmap_playback_delay(pcm);
>  	return 0;
>  }
>  -- 
> 2.5.5
>