[ALSA] PCM interface - rename SNDRV_PCM_TSTAMP_MMAP to SNDRV_PCM_TSTAMP_ENABLE

Change semantics for SNDRV_PCM_TSTAMP_MMAP. Doing timestamping only in
the interrupt handler might cause that hw_ptr is not related to actual
timestamp. With this change, grab timestamp at every hw_ptr update to
have always valid timestamp + ring buffer position pair.
With this change, SNDRV_PCM_TSTAMP_MMAP was renamed to
SNDRV_PCM_TSTAMP_ENABLE. It's no regression (I think).
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

include/sound/asound.h

@@ -354,8 +354,8 @@ struct snd_pcm_hw_params {
 
 enum {
 	SNDRV_PCM_TSTAMP_NONE = 0,
-	SNDRV_PCM_TSTAMP_MMAP,
-	SNDRV_PCM_TSTAMP_LAST = SNDRV_PCM_TSTAMP_MMAP,
+	SNDRV_PCM_TSTAMP_ENABLE,
+	SNDRV_PCM_TSTAMP_LAST = SNDRV_PCM_TSTAMP_ENABLE,
 };
 
 struct snd_pcm_sw_params {

sound/core/pcm.c

@@ -227,7 +227,7 @@ static char *snd_pcm_subformat_names[] = {
 
 static char *snd_pcm_tstamp_mode_names[] = {
 	TSTAMP(NONE),
-	TSTAMP(MMAP),
+	TSTAMP(ENABLE),
 };
 
 static const char *snd_pcm_stream_name(int stream)

sound/core/pcm_lib.c

@@ -144,6 +144,8 @@ static inline snd_pcm_uframes_t snd_pcm_update_hw_ptr_pos(struct snd_pcm_substre
 {
 	snd_pcm_uframes_t pos;
 
+	if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
+		snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);
 	pos = substream->ops->pointer(substream);
 	if (pos == SNDRV_PCM_POS_XRUN)
 		return pos; /* XRUN */
@@ -186,8 +188,6 @@ static inline int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *subs
 	snd_pcm_uframes_t new_hw_ptr, hw_ptr_interrupt;
 	snd_pcm_sframes_t delta;
 
-	if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_MMAP)
-		snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);
 	pos = snd_pcm_update_hw_ptr_pos(substream, runtime);
 	if (pos == SNDRV_PCM_POS_XRUN) {
 		xrun(substream);

sound/core/pcm_native.c

@@ -580,9 +580,15 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
 	if (status->state == SNDRV_PCM_STATE_OPEN)
 		goto _end;
 	status->trigger_tstamp = runtime->trigger_tstamp;
-	if (snd_pcm_running(substream))
+	if (snd_pcm_running(substream)) {
 		snd_pcm_update_hw_ptr(substream);
+		if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
+			status->tstamp = runtime->status->tstamp;
+			goto _tstamp_end;
+		}
+	}
 	snd_pcm_gettime(runtime, &status->tstamp);
+ _tstamp_end:
 	status->appl_ptr = runtime->control->appl_ptr;
 	status->hw_ptr = runtime->status->hw_ptr;
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {