[alsa-devel] [PATCH] [ALSA] add SNDRV_PCM_TRIGGER_DRAIN trigger

[Takashi Iwai]

At Wed, 31 Dec 2014 11:03:40 +0800,
libin.yang at intel.com wrote:
> 
> From: Libin Yang <libin.yang at intel.com>
> 
> Add SNDRV_PCM_TRIGGER_DRAIN trigger for pcm drain.
> 
> Some audio devices require notification of drain events
> in order to properly drain and shutdown an audio stream.
> 
> Signed-off-by: Libin Yang <libin.yang at intel.com>
> ---
>  include/sound/pcm.h         |  1 +
>  include/uapi/sound/asound.h |  1 +
>  sound/core/pcm_native.c     | 10 +++++++++-
>  3 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> index 3652c94..bf32cea 100644
> --- a/include/sound/pcm.h
> +++ b/include/sound/pcm.h
> @@ -106,6 +106,7 @@ struct snd_pcm_ops {
>  #define SNDRV_PCM_TRIGGER_PAUSE_RELEASE	4
>  #define SNDRV_PCM_TRIGGER_SUSPEND	5
>  #define SNDRV_PCM_TRIGGER_RESUME	6
> +#define SNDRV_PCM_TRIGGER_DRAIN		7
>  
>  #define SNDRV_PCM_POS_XRUN		((snd_pcm_uframes_t)-1)
>  
> diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
> index 1f23cd6..0e88e7a 100644
> --- a/include/uapi/sound/asound.h
> +++ b/include/uapi/sound/asound.h
> @@ -268,6 +268,7 @@ typedef int __bitwise snd_pcm_subformat_t;
>  #define SNDRV_PCM_INFO_SYNC_START	0x00400000	/* pcm support some kind of sync go */
>  #define SNDRV_PCM_INFO_NO_PERIOD_WAKEUP	0x00800000	/* period wakeup can be disabled */
>  #define SNDRV_PCM_INFO_HAS_WALL_CLOCK   0x01000000      /* has audio wall clock for audio/system time sync */
> +#define SNDRV_PCM_INFO_DRAIN_TRIGGER	0x40000000		/* internal kernel flag - trigger in drain */
>  #define SNDRV_PCM_INFO_FIFO_IN_FRAMES	0x80000000	/* internal kernel flag - FIFO size is in frames */
>  
>  typedef int __bitwise snd_pcm_state_t;
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index 095d957..bd57f6e 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -420,7 +420,8 @@ int snd_pcm_hw_refine(struct snd_pcm_substream *substream,
>  
>  	hw = &substream->runtime->hw;
>  	if (!params->info) {
> -		params->info = hw->info & ~SNDRV_PCM_INFO_FIFO_IN_FRAMES;
> +		params->info = hw->info & ~SNDRV_PCM_INFO_FIFO_IN_FRAMES
> +			& ~SNDRV_PCM_INFO_DRAIN_TRIGGER;

Usually written like ~(A | B).


Takashi

>  		if (!hw_support_mmap(substream))
>  			params->info &= ~(SNDRV_PCM_INFO_MMAP |
>  					  SNDRV_PCM_INFO_MMAP_VALID);
> @@ -1566,6 +1567,13 @@ static int snd_pcm_do_drain_init(struct snd_pcm_substream *substream, int state)
>  			snd_pcm_post_stop(substream, new_state);
>  		}
>  	}
> +
> +	if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
> +		substream->runtime->trigger_master == substream &&
> +		(substream->runtime->hw.info & SNDRV_PCM_INFO_DRAIN_TRIGGER))
> +		return substream->ops->trigger(substream,
> +				SNDRV_PCM_TRIGGER_DRAIN);
> +
>  	return 0;
>  }
>  
> -- 
> 1.9.1
>