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

[Sriram Periyasamy]

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(-)

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);
-- 
2.7.4