From: Ramesh Babu ramesh.babu@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@intel.com Signed-off-by: Sriram Periyasamy sriramx.periyasamy@intel.com ---
Please find the reference for previous discussion at [1].
[1] https://patchwork.kernel.org/patch/10191483/
aplay/aplay.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/aplay/aplay.c b/aplay/aplay.c index bbd7fffa04fc..6eb9d3b04d92 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);