alsa-lib.patches/alsa-lib-50.patch

diff -aruN alsa-lib-1.0.27.2/src/pcm/pcm_direct.c alsa-lib-1.0.27.2.N/src/pcm/pcm_direct.c
--- alsa-lib-1.0.27.2/src/pcm/pcm_direct.c	2013-07-08 05:31:36.000000000 -0700
+++ alsa-lib-1.0.27.2.N/src/pcm/pcm_direct.c	2017-07-13 13:18:48.424261391 -0700
@@ -91,13 +91,20 @@
 int snd_pcm_direct_shm_create_or_connect(snd_pcm_direct_t *dmix)
 {
 	struct shmid_ds buf;
-	int tmpid, err;
+	int tmpid, err, first_instance = 0;
 	
 retryget:
 	dmix->shmid = shmget(dmix->ipc_key, sizeof(snd_pcm_direct_share_t),
-			     IPC_CREAT | dmix->ipc_perm);
+			     dmix->ipc_perm);
+	if (dmix->shmid < 0 && errno == ENOENT) {
+		if ((dmix->shmid = shmget(dmix->ipc_key, sizeof(snd_pcm_direct_share_t),
+					     IPC_CREAT | IPC_EXCL | dmix->ipc_perm)) != -1)
+			first_instance = 1;
+		else if (errno == EEXIST)
+			goto retryget;
+	}
 	err = -errno;
-	if (dmix->shmid < 0){
+	if (dmix->shmid < 0) {
 		if (errno == EINVAL)
 		if ((tmpid = shmget(dmix->ipc_key, 0, dmix->ipc_perm)) != -1)
 		if (!shmctl(tmpid, IPC_STAT, &buf))
@@ -119,7 +126,7 @@
 		snd_pcm_direct_shm_discard(dmix);
 		return err;
 	}
-	if (buf.shm_nattch == 1) {	/* we're the first user, clear the segment */
+	if (first_instance) {	/* we're the first user, clear the segment */
 		memset(dmix->shmptr, 0, sizeof(snd_pcm_direct_share_t));
 		if (dmix->ipc_gid >= 0) {
 			buf.shm_perm.gid = dmix->ipc_gid;
@@ -130,6 +137,7 @@
 	} else {
 		if (dmix->shmptr->magic != SND_PCM_DIRECT_MAGIC) {
 			snd_pcm_direct_shm_discard(dmix);
+			SNDERR("Error in second instance");
 			return -EINVAL;
 		}
 	}
diff -aruN alsa-lib-1.0.27.2/src/pcm/pcm_dmix.c alsa-lib-1.0.27.2.N/src/pcm/pcm_dmix.c
--- alsa-lib-1.0.27.2/src/pcm/pcm_dmix.c	2013-07-08 05:31:36.000000000 -0700
+++ alsa-lib-1.0.27.2.N/src/pcm/pcm_dmix.c	2017-07-13 13:15:33.874553985 -0700
@@ -1013,6 +1013,7 @@
 	dmix->max_periods = opts->max_periods;
 	dmix->sync_ptr = snd_pcm_dmix_sync_ptr;
 
+ retry:
 	if (first_instance) {
 		/* recursion is already checked in
 		   snd_pcm_direct_get_slave_ipc_offset() */
@@ -1069,6 +1070,13 @@
 						 SND_PCM_APPEND,
 						 NULL);
 			if (ret < 0) {
+				/* all other streams have been closed;
+				 * retry as the first instance
+				 */
+				if (ret == -EBADFD) {
+					first_instance = 1;
+					goto retry;
+				}
 				SNDERR("unable to open slave");
 				goto _err;
 			}