Get the frames only after pcm_start state

Author: Cuda-Chen

virtio-snd.c

@@ -321,6 +321,8 @@ typedef struct {
     // PCM frame doubly-ended queue
     vsnd_buf_queue_node_t buf;
     struct list_head buf_queue_head;
+    // PCM frame immediate buffer;
+    void *immediate;
 
     // playback control
     vsnd_stream_sel_t v;
@@ -552,7 +554,7 @@ static void virtio_snd_read_pcm_prepare(const virtio_snd_pcm_hdr_t *query,
     /* CNFA only accept frame with signed 16-bit data in little-endian. */
     props->audio_host =
         CNFAInit(NULL, "semu-virtio-snd", virtio_snd_cb, rate, 0, channels, 0,
-                 period_bytes / VSND_CNFA_FRAME_SZ, NULL, NULL, &props->v);
+                 cnfa_period_frames, NULL, NULL, &props->v);
     uint32_t sz = props->pp.buffer_bytes;
     props->ring.buffer = (void *) malloc(sizeof(void) * sz);
     props->ring.prod.head = 0;
@@ -567,6 +569,7 @@ static void virtio_snd_read_pcm_prepare(const virtio_snd_pcm_hdr_t *query,
     pthread_cond_init(&props->ring.readable, NULL);
     pthread_cond_init(&props->ring.writable, NULL);
     INIT_LIST_HEAD(&props->buf_queue_head);
+    props->immediate = (void *)malloc(sizeof(void) * cnfa_period_bytes);
 #if WRITEOUT
     outfile = fopen("out_enque.bin", "wb");
 #endif
@@ -648,6 +651,7 @@ static void virtio_snd_read_pcm_release(const virtio_snd_pcm_hdr_t *query,
 #endif
     /* Tear down the PCM ring buffer. */
     free(props->ring.buffer);
+    free(props->immediate);
     pthread_mutex_destroy(&props->ring.lock);
     pthread_cond_destroy(&props->ring.readable);
     pthread_cond_destroy(&props->ring.writable);
@@ -710,26 +714,46 @@ static void __virtio_snd_frame_dequeue(short *out,
             "cons_head %" PRIu32 " cons_next %" PRIu32 " prod_tail %" PRIu32
             " mask %" PRIu32 " idx %" PRIu32 "\n",
             cons_head, cons_next, prod_tail, mask, idx);
-    if (idx + n < size) {
+    /*if (idx + n < size) {
         memcpy(out, props->ring.buffer + idx, n);
     } else {
         memcpy(out, props->ring.buffer + idx, size - idx);
         memcpy(out + (size - idx), props->ring.buffer, n - (size - idx));
         fprintf(stderr, "=== start %" PRIu32 " end %" PRIu32 "\n", size - idx,
                 n - (size - idx));
-    }
+    }*/
     VSND_COMPILER_BARRIER;
 
     props->ring.cons.tail = cons_next;
 
-    /*uint32_t len = 0;
-    while (!list_empty(&props->buf_queue_head) && len < n) {
+    uint32_t written_bytes = 0;
+    memset(props->immediate, 0, sizeof(void) * n);
+    while (!list_empty(&props->buf_queue_head) && written_bytes < n) {
         vsnd_buf_queue_node_t *node =
             list_first_entry(&props->buf_queue_head, vsnd_buf_queue_node_t, q);
-        list_del(&node->q);
-        memcpy(out, node->addr, node->len);
-        len += node->len;
-    }*/
+        uint32_t left = n - written_bytes;
+        uint32_t actual = node->len - node->pos;
+        uint32_t len = left < actual ? left : actual; /* Naive min implementation */
+
+        fprintf(stderr,
+                "--- left %" PRIu32 " actual %" PRIu32 " len %" PRIu32 " written %" PRIu32 "\n",
+                left,
+                actual,
+                len,
+                written_bytes);
+
+        memcpy(
+                props->immediate + written_bytes,
+                node->addr,
+                len);
+
+        written_bytes += len;
+        node->pos += len;
+        if(node->pos >= node->len)
+            list_del(&node->q);
+    }
+    fprintf(stderr, "*** written %" PRIu32 " out n %" PRIu32 "\n", written_bytes, n);
+    memcpy(out, props->immediate, n);
 
     props->ring.buf_ev_notity--;
     pthread_cond_signal(&props->ring.writable);