pcm: ioplug: Use boundary for wrap around

if requested by the IO plugin

Without this changes an IO plugin is not able to report
that buffer_size frames were read from the buffer.
When the buffer was full this is a valid action and
has not to be handled as an under run.

For example when the hw_ptr will be updated with
hw_ptr += buffer_size
and it is using the buffer_size as wrap around
hw_ptr %= buffer_size
would result in the same value as before the add operation.

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/pcm_ioplug.h b/include/pcm_ioplug.h
index 1c84594..e75f973 100644 (file)
--- a/include/pcm_ioplug.h
+++ b/include/pcm_ioplug.h
@@ -65,6 +65,8 @@ typedef snd_pcm_ioplug_callback snd_pcm_ioplug_callback_t;
  */
 #define SND_PCM_IOPLUG_FLAG_LISTED     (1<<0)          /**< list up this PCM */
 #define SND_PCM_IOPLUG_FLAG_MONOTONIC  (1<<1)          /**< monotonic timestamps */
+/** hw pointer wrap around at boundary instead of buffer_size */
+#define SND_PCM_IOPLUG_FLAG_BOUNDARY_WA        (1<<2)
 
 /*
  * Protocol version
@@ -133,6 +135,9 @@ struct snd_pcm_ioplug_callback {
        int (*stop)(snd_pcm_ioplug_t *io);
        /**
         * get the current DMA position; required, called inside mutex lock
+        * \return buffer position up to buffer_size or
+        * when #SND_PCM_IOPLUG_FLAG_BOUNDARY_WA flag is set up to boundary or
+        * a negative error code for Xrun
         */
        snd_pcm_sframes_t (*pointer)(snd_pcm_ioplug_t *io);
        /**

diff --git a/src/pcm/pcm_ioplug.c b/src/pcm/pcm_ioplug.c
index 7a782e6..9970646 100644 (file)
--- a/src/pcm/pcm_ioplug.c
+++ b/src/pcm/pcm_ioplug.c
@@ -42,7 +42,7 @@ const char *_snd_module_pcm_ioplug = "";
 typedef struct snd_pcm_ioplug_priv {
        snd_pcm_ioplug_t *data;
        struct snd_ext_parm params[SND_PCM_IOPLUG_HW_PARAMS];
-       unsigned int last_hw;
+       snd_pcm_uframes_t last_hw;
        snd_pcm_uframes_t avail_max;
        snd_htimestamp_t trigger_tstamp;
 } ioplug_priv_t;
@@ -56,13 +56,18 @@ static void snd_pcm_ioplug_hw_ptr_update(snd_pcm_t *pcm)
 
        hw = io->data->callback->pointer(io->data);
        if (hw >= 0) {
-               unsigned int delta;
-               if ((unsigned int)hw >= io->last_hw)
+               snd_pcm_uframes_t delta;
+
+               if ((snd_pcm_uframes_t)hw >= io->last_hw)
                        delta = hw - io->last_hw;
-               else
-                       delta = pcm->buffer_size + hw - io->last_hw;
+               else {
+                       const snd_pcm_uframes_t wrap_point =
+                               (io->data->flags & SND_PCM_IOPLUG_FLAG_BOUNDARY_WA) ?
+                                       pcm->boundary : pcm->buffer_size;
+                       delta = wrap_point + hw - io->last_hw;
+               }
                snd_pcm_mmap_hw_forward(io->data->pcm, delta);
-               io->last_hw = hw;
+               io->last_hw = (snd_pcm_uframes_t)hw;
        } else
                io->data->state = SNDRV_PCM_STATE_XRUN;
 }