pcm: null plugin - fix the avail count

The automatic threshold start is not activated when the wrong avail
count is returned in the prepared state.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/pcm/pcm_null.c b/src/pcm/pcm_null.c
index f1d2f91..655261f 100644 (file)
--- a/src/pcm/pcm_null.c
+++ b/src/pcm/pcm_null.c
@@ -80,6 +80,20 @@ static int snd_pcm_null_info(snd_pcm_t *pcm, snd_pcm_info_t * info)
        return 0;
 }
 
+static snd_pcm_sframes_t snd_pcm_null_avail_update(snd_pcm_t *pcm)
+{
+       snd_pcm_null_t *null = pcm->private_data;
+        if (null->state == SND_PCM_STATE_PREPARED) {
+                /* it is required to return the correct avail count for */
+                /* the prepared stream, otherwise the start is not called */
+                if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
+                        return snd_pcm_mmap_playback_avail(pcm);
+                else
+                        return snd_pcm_mmap_capture_avail(pcm);
+        }
+       return pcm->buffer_size;
+}
+
 static int snd_pcm_null_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
 {
        snd_pcm_null_t *null = pcm->private_data;
@@ -87,8 +101,8 @@ static int snd_pcm_null_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
        status->state = null->state;
        status->trigger_tstamp = null->trigger_tstamp;
        gettimestamp(&status->tstamp, pcm->monotonic);
-       status->avail = pcm->buffer_size;
-       status->avail_max = status->avail;
+       status->avail = snd_pcm_null_avail_update(pcm);
+       status->avail_max = pcm->buffer_size;
        return 0;
 }
 
@@ -109,20 +123,18 @@ static int snd_pcm_null_delay(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_sframes_t
        return 0;
 }
 
-static int snd_pcm_null_prepare(snd_pcm_t *pcm)
+static int snd_pcm_null_reset(snd_pcm_t *pcm)
 {
-       snd_pcm_null_t *null = pcm->private_data;
-       null->state = SND_PCM_STATE_PREPARED;
        *pcm->appl.ptr = 0;
        *pcm->hw.ptr = 0;
        return 0;
 }
 
-static int snd_pcm_null_reset(snd_pcm_t *pcm)
+static int snd_pcm_null_prepare(snd_pcm_t *pcm)
 {
-       *pcm->appl.ptr = 0;
-       *pcm->hw.ptr = 0;
-       return 0;
+       snd_pcm_null_t *null = pcm->private_data;
+       null->state = SND_PCM_STATE_PREPARED;
+       return snd_pcm_null_reset(pcm);
 }
 
 static int snd_pcm_null_start(snd_pcm_t *pcm)
@@ -251,11 +263,6 @@ static snd_pcm_sframes_t snd_pcm_null_mmap_commit(snd_pcm_t *pcm,
        return snd_pcm_null_forward(pcm, size);
 }
 
-static snd_pcm_sframes_t snd_pcm_null_avail_update(snd_pcm_t *pcm)
-{
-       return pcm->buffer_size;
-}
-
 static int snd_pcm_null_hw_refine(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params)
 {
        int err = snd_pcm_hw_refine_soft(pcm, params);