On 02/11/16 14:17, Alan Young wrote:
I am wondering if the earlier call to snd_pcm_dshare_sync_ptr(pcm),
which I guess forms the basis for the result of
snd_pcm_mmap_playback_delay(pcm), may be operating on a different set
of data (because of an intervening interrupt) to that returned by
snd_pcm_status().
How about this for a revised patch. It seems to be working well for me
(so far). I am not suggesting that this should be considered final yet.
Alan.
diff --git a/src/pcm/pcm_dshare.c b/src/pcm/pcm_dshare.c
index 58e47bb..568448c 100644
--- a/src/pcm/pcm_dshare.c
+++ b/src/pcm/pcm_dshare.c
@@ -157,23 +157,14 @@ static void snd_pcm_dshare_sync_area(snd_pcm_t *pcm)
/*
* synchronize hardware pointer (hw_ptr) with ours
*/
-static int snd_pcm_dshare_sync_ptr(snd_pcm_t *pcm)
+static int snd_pcm_dshare_sync_ptr0(snd_pcm_t *pcm, snd_pcm_uframes_t slave_hw_ptr)
{
snd_pcm_direct_t *dshare = pcm->private_data;
- snd_pcm_uframes_t slave_hw_ptr, old_slave_hw_ptr, avail;
+ snd_pcm_uframes_t old_slave_hw_ptr, avail;
snd_pcm_sframes_t diff;
- switch (snd_pcm_state(dshare->spcm)) {
- case SND_PCM_STATE_DISCONNECTED:
- dshare->state = SNDRV_PCM_STATE_DISCONNECTED;
- return -ENODEV;
- default:
- break;
- }
- if (dshare->slowptr)
- snd_pcm_hwsync(dshare->spcm);
old_slave_hw_ptr = dshare->slave_hw_ptr;
- slave_hw_ptr = dshare->slave_hw_ptr = *dshare->spcm->hw.ptr;
+ dshare->slave_hw_ptr = slave_hw_ptr;
diff = slave_hw_ptr - old_slave_hw_ptr;
if (diff == 0) /* fast path */
return 0;
@@ -207,6 +198,24 @@ static int snd_pcm_dshare_sync_ptr(snd_pcm_t *pcm)
return 0;
}
+static int snd_pcm_dshare_sync_ptr(snd_pcm_t *pcm)
+{
+ snd_pcm_direct_t *dshare = pcm->private_data;
+
+ switch (snd_pcm_state(dshare->spcm)) {
+ case SND_PCM_STATE_DISCONNECTED:
+ dshare->state = SNDRV_PCM_STATE_DISCONNECTED;
+ return -ENODEV;
+ default:
+ break;
+ }
+
+ if (dshare->slowptr)
+ snd_pcm_hwsync(dshare->spcm);
+
+ return snd_pcm_dshare_sync_ptr0(pcm, *dshare->spcm->hw.ptr);
+}
+
/*
* plugin implementation
*/
@@ -215,22 +224,24 @@ static int snd_pcm_dshare_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
{
snd_pcm_direct_t *dshare = pcm->private_data;
+ memset(status, 0, sizeof(*status));
+ snd_pcm_status(dshare->spcm, status);
+
switch (dshare->state) {
case SNDRV_PCM_STATE_DRAINING:
case SNDRV_PCM_STATE_RUNNING:
- snd_pcm_dshare_sync_ptr(pcm);
+ snd_pcm_dshare_sync_ptr0(pcm, status->hw_ptr);
+ status->delay += snd_pcm_mmap_playback_delay(pcm)
+ + status->avail - dshare->spcm->buffer_size;
break;
default:
break;
}
- memset(status, 0, sizeof(*status));
- snd_pcm_status(dshare->spcm, status);
- status->state = snd_pcm_state(dshare->spcm);
+
status->trigger_tstamp = dshare->trigger_tstamp;
status->avail = snd_pcm_mmap_playback_avail(pcm);
status->avail_max = status->avail > dshare->avail_max ? status->avail : dshare->avail_max;
dshare->avail_max = 0;
- status->delay = snd_pcm_mmap_playback_delay(pcm);
return 0;
}
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