[ALSA] Fix substream selection in PCM and rawmidi

The PCM and rawmidi substreams can be selected explicitly by opening
control handle and set via *_PREFER_SUBDEVICE ioctl.  But, when
multiple controls are opened, the driver gets confused.
The patch fixes the initialization of prefer_*_subdevice and the
check of multiple controls.  The first set subdevice is picked up
as the valid one.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

3 files changed, 6 insertions, 2 deletions

diff --git a/sound/core/control.c b/sound/core/control.c
index 31ad58154c06..ac1442682eac 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -75,6 +75,8 @@ static int snd_ctl_open(struct inode *inode, struct file *file)
         init_waitqueue_head(&ctl->change_sleep);
         spin_lock_init(&ctl->read_lock);
         ctl->card = card;
+        ctl->prefer_pcm_subdevice = -1;
+        ctl->prefer_rawmidi_subdevice = -1;
         ctl->pid = current->pid;
         file->private_data = ctl;
         write_lock_irqsave(&card->ctl_files_rwlock, flags);
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index f52178abf120..ed3b09469560 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -792,7 +792,8 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
                 kctl = snd_ctl_file(list);
                 if (kctl->pid == current->pid) {
                         prefer_subdevice = kctl->prefer_pcm_subdevice;
-                        break;
+                        if (prefer_subdevice != -1)
+                                break;
                 }
         }
         up_read(&card->controls_rwsem);
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 8a2bdfae63e3..269c467ca9bb 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -430,7 +430,8 @@ static int snd_rawmidi_open(struct inode *inode, struct file *file)
                         kctl = snd_ctl_file(list);
                         if (kctl->pid == current->pid) {
                                 subdevice = kctl->prefer_rawmidi_subdevice;
-                                break;
+                                if (subdevice != -1)
+                                        break;
                         }
                 }
                 up_read(&card->controls_rwsem);