[PATCH] ALSA: compress: allow pause and resume during draining

["Gyeongtaek Lee" <gt82.lee@xxxxxxxxxxx>]

With a stream with low bitrate, user can't pause or resume the stream
near the end of the stream because current ALSA doesn't allow it.
If the stream has very low bitrate enough to store whole stream into
the buffer, user can't do anything except stop the stream and then
restart it from the first.
If pause and resume is allowed during draining, user experience can be
enhanced.

Signed-off-by: Gyeongtaek Lee <gt82.lee@xxxxxxxxxxx>
---
 sound/core/compress_offload.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index 0e53f6f31916..90b437f302a0 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -708,11 +708,20 @@ static int snd_compr_pause(struct snd_compr_stream *stream)
 {
 	int retval;
 
-	if (stream->runtime->state != SNDRV_PCM_STATE_RUNNING)
+	switch (stream->runtime->state) {
+	case SNDRV_PCM_STATE_RUNNING:
+		retval = stream->ops->trigger(stream,
+			SNDRV_PCM_TRIGGER_PAUSE_PUSH);
+		if (!retval)
+			stream->runtime->state = SNDRV_PCM_STATE_PAUSED;
+		break;
+	case SNDRV_PCM_STATE_DRAINING:
+		retval = stream->ops->trigger(stream,
+			SNDRV_PCM_TRIGGER_PAUSE_PUSH);
+		break;
+	default:
 		return -EPERM;
-	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_PAUSE_PUSH);
-	if (!retval)
-		stream->runtime->state = SNDRV_PCM_STATE_PAUSED;
+	}
 	return retval;
 }
 
@@ -720,11 +729,20 @@ static int snd_compr_resume(struct snd_compr_stream *stream)
 {
 	int retval;
 
-	if (stream->runtime->state != SNDRV_PCM_STATE_PAUSED)
+	switch (stream->runtime->state) {
+	case SNDRV_PCM_STATE_PAUSED:
+		retval = stream->ops->trigger(stream,
+			SNDRV_PCM_TRIGGER_PAUSE_RELEASE);
+		if (!retval)
+			stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
+		break;
+	case SNDRV_PCM_STATE_DRAINING:
+		retval = stream->ops->trigger(stream,
+			SNDRV_PCM_TRIGGER_PAUSE_RELEASE);
+		break;
+	default:
 		return -EPERM;
-	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_PAUSE_RELEASE);
-	if (!retval)
-		stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
+	}
 	return retval;
 }
 

base-commit: a1b8638ba1320e6684aa98233c15255eb803fac7
-- 
2.21.0