[alsa-devel] [alsa-utils] [PATCH] Add support for no-rewind flag in aplay utility

[Takashi Sakamoto]

Hi,

On Jan 30 2018 18:34, Sriram Periyasamy wrote:
> From: Ramesh Babu <ramesh.babu at intel.com>
> 
> The "no-rewind" flag is introduced in alsa.
> Application can use this flag to assure kernel driver
> that rewind won't be exercised. Driver could use this
> flag to alter it's buffering scheme to optimize power
> and performance.
> 
> Signed-off-by: Ramesh Babu <ramesh.babu at intel.com>
> Signed-off-by: Sriram Periyasamy <sriramx.periyasamy at intel.com>
> ---
>  aplay/aplay.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)

Current implementation of 'aplay' doesn't perform rewinding/forwarding,
thus an additional of this option is surplus.

> diff --git a/aplay/aplay.c b/aplay/aplay.c
> index 6b740c281f8e..b50602a59024 100644
> --- a/aplay/aplay.c
> +++ b/aplay/aplay.c
> @@ -108,6 +108,7 @@ static snd_pcm_stream_t stream = SND_PCM_STREAM_PLAYBACK;
>  static int mmap_flag = 0;
>  static int interleaved = 1;
>  static int nonblock = 0;
> +static int no_rewind = 0;
>  static volatile sig_atomic_t in_aborting = 0;
>  static u_char *audiobuf = NULL;
>  static snd_pcm_uframes_t chunk_size = 0;
> @@ -229,6 +230,7 @@ _("Usage: %s [OPTION]... [FILE]...\n"
>  "-I, --separate-channels one file for each channel\n"
>  "-i, --interactive       allow interactive operation from stdin\n"
>  "-m, --chmap=ch1,ch2,..  Give the channel map to override or follow\n"
> +"-w, --no-rewind         enables no rewind mode\n"
>  "    --disable-resample  disable automatic rate resample\n"
>  "    --disable-channels  disable automatic channel conversions\n"
>  "    --disable-format    disable automatic format conversions\n"
> @@ -470,7 +472,7 @@ int main(int argc, char *argv[])
>  {
>  	int duration_or_sample = 0;
>  	int option_index;
> -	static const char short_options[] = "hnlLD:qt:c:f:r:d:s:MNF:A:R:T:B:vV:IPCi"
> +	static const char short_options[] = "hnlLD:qt:c:f:r:d:s:w:MNF:A:R:T:B:vV:IPCi"
>  #ifdef CONFIG_SUPPORT_CHMAP
>  		"m:"
>  #endif
> @@ -514,6 +516,7 @@ int main(int argc, char *argv[])
>  		{"process-id-file", 1, 0, OPT_PROCESS_ID_FILE},
>  		{"use-strftime", 0, 0, OPT_USE_STRFTIME},
>  		{"interactive", 0, 0, 'i'},
> +		{"no-rewind", 0, 0, 'w'},
>  		{"dump-hw-params", 0, 0, OPT_DUMP_HWPARAMS},
>  		{"fatal-errors", 0, 0, OPT_FATAL_ERRORS},
>  #ifdef CONFIG_SUPPORT_CHMAP
> @@ -753,6 +756,9 @@ int main(int argc, char *argv[])
>  		case 'i':
>  			interactive = 1;
>  			break;
> +		case 'w':
> +			no_rewind = 1;
> +			break;
>  		case OPT_DISABLE_RESAMPLE:
>  			open_mode |= SND_PCM_NO_AUTO_RESAMPLE;
>  			break;
> @@ -1396,6 +1402,12 @@ static void set_params(void)
>  							     &buffer_frames);
>  	}
>  	assert(err >= 0);
> +
> +	if (no_rewind) {
> +		err = snd_pcm_hw_params_set_no_rewind(handle, params, 1);
> +		assert(err >= 0);
> +	}
> +
>  	monotonic = snd_pcm_hw_params_is_monotonic(params);
>  	can_pause = snd_pcm_hw_params_can_pause(params);
>  	err = snd_pcm_hw_params(handle, params);


Regards

Takashi Sakamoto