Fixed pcm_start when pcm is linked to other pcm device

When pcm device is linked to other pcm device,
the start call may be triggered by other pcm device.

Handle this condition by checing pcm state before start call.

Signed-off-by: Miguel Gaio <mgaio35@gmail.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/pcm.c b/src/pcm.c
index 7ea58bd..f1d733f 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -1203,11 +1203,14 @@ int pcm_start(struct pcm *pcm)
     if (prepare_error)
         return prepare_error;
 
-    if (pcm->flags & PCM_MMAP)
-        pcm_sync_ptr(pcm, 0);
+    /* if pcm is linked, it may be already started by other pcm */
+    /* check pcm state is not in running state */
+    pcm_sync_ptr(pcm, 0);
 
-    if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0)
-        return oops(pcm, errno, "cannot start channel");
+    if (pcm->mmap_status->state != PCM_STATE_RUNNING) {
+        if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0)
+            return oops(pcm, errno, "cannot start channel");
+    }
 
     pcm->running = 1;
     return 0;