6 files changed, 40 insertions, 28 deletions

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 9feb00c831a0..4eabafa5b037 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -126,7 +126,7 @@ static void snd_usb_stream_disconnect(struct list_head *head)
         for (idx = 0; idx < 2; idx++) {
                 subs = &as->substream[idx];
                 if (!subs->num_formats)
-                        return;
+                        continue;
                 snd_usb_release_substream_urbs(subs, 1);
                 subs->interface = -1;
         }
@@ -216,6 +216,11 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
         }
 
         switch (protocol) {
+        default:
+                snd_printdd(KERN_WARNING "unknown interface protocol %#02x, assuming v1\n",
+                            protocol);
+                /* fall through */
+
         case UAC_VERSION_1: {
                 struct uac1_ac_header_descriptor *h1 = control_header;
 
@@ -253,10 +258,6 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
 
                 break;
         }
-
-        default:
-                snd_printk(KERN_ERR "unknown protocol version 0x%02x\n", protocol);
-                return -EINVAL;
         }
 
         return 0;
@@ -465,7 +466,13 @@ static void *snd_usb_audio_probe(struct usb_device *dev,
                         goto __error;
         }
 
-        chip->ctrl_intf = alts;
+        /*
+         * For devices with more than one control interface, we assume the
+         * first contains the audio controls. We might need a more specific
+         * check here in the future.
+         */
+        if (!chip->ctrl_intf)
+                chip->ctrl_intf = alts;
 
         if (err > 0) {
                 /* create normal USB audio interfaces */
diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index b853f8df794f..7754a1034545 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -295,12 +295,11 @@ int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
 
         switch (altsd->bInterfaceProtocol) {
         case UAC_VERSION_1:
+        default:
                 return set_sample_rate_v1(chip, iface, alts, fmt, rate);
 
         case UAC_VERSION_2:
                 return set_sample_rate_v2(chip, iface, alts, fmt, rate);
         }
-
-        return -EINVAL;
 }
 
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 1a701f1e8f50..ef0a07e34844 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -275,6 +275,12 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
 
                 /* get audio formats */
                 switch (protocol) {
+                default:
+                        snd_printdd(KERN_WARNING "%d:%u:%d: unknown interface protocol %#02x, assuming v1\n",
+                                    dev->devnum, iface_no, altno, protocol);
+                        protocol = UAC_VERSION_1;
+                        /* fall through */
+
                 case UAC_VERSION_1: {
                         struct uac1_as_header_descriptor *as =
                                 snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
@@ -336,11 +342,6 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
                                    dev->devnum, iface_no, altno, as->bTerminalLink);
                         continue;
                 }
-
-                default:
-                        snd_printk(KERN_ERR "%d:%u:%d : unknown interface protocol %04x\n",
-                                   dev->devnum, iface_no, altno, protocol);
-                        continue;
                 }
 
                 /* get format type */
diff --git a/sound/usb/format.c b/sound/usb/format.c
index 3a1375459c06..69148212aa70 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -49,7 +49,8 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
         u64 pcm_formats;
 
         switch (protocol) {
-        case UAC_VERSION_1: {
+        case UAC_VERSION_1:
+        default: {
                 struct uac_format_type_i_discrete_descriptor *fmt = _fmt;
                 sample_width = fmt->bBitResolution;
                 sample_bytes = fmt->bSubframeSize;
@@ -64,9 +65,6 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
                 format <<= 1;
                 break;
         }
-
-        default:
-                return -EINVAL;
         }
 
         pcm_formats = 0;
@@ -384,6 +382,10 @@ static int parse_audio_format_i(struct snd_usb_audio *chip,
          * audio class v2 uses class specific EP0 range requests for that.
          */
         switch (protocol) {
+        default:
+                snd_printdd(KERN_WARNING "%d:%u:%d : invalid protocol version %d, assuming v1\n",
+                           chip->dev->devnum, fp->iface, fp->altsetting, protocol);
+                /* fall through */
         case UAC_VERSION_1:
                 fp->channels = fmt->bNrChannels;
                 ret = parse_audio_format_rates_v1(chip, fp, (unsigned char *) fmt, 7);
@@ -392,10 +394,6 @@ static int parse_audio_format_i(struct snd_usb_audio *chip,
                 /* fp->channels is already set in this case */
                 ret = parse_audio_format_rates_v2(chip, fp);
                 break;
-        default:
-                snd_printk(KERN_ERR "%d:%u:%d : invalid protocol version %d\n",
-                           chip->dev->devnum, fp->iface, fp->altsetting, protocol);
-                return -EINVAL;
         }
 
         if (fp->channels < 1) {
@@ -438,6 +436,10 @@ static int parse_audio_format_ii(struct snd_usb_audio *chip,
         fp->channels = 1;
 
         switch (protocol) {
+        default:
+                snd_printdd(KERN_WARNING "%d:%u:%d : invalid protocol version %d, assuming v1\n",
+                           chip->dev->devnum, fp->iface, fp->altsetting, protocol);
+                /* fall through */
         case UAC_VERSION_1: {
                 struct uac_format_type_ii_discrete_descriptor *fmt = _fmt;
                 brate = le16_to_cpu(fmt->wMaxBitRate);
@@ -456,10 +458,6 @@ static int parse_audio_format_ii(struct snd_usb_audio *chip,
                 ret = parse_audio_format_rates_v2(chip, fp);
                 break;
         }
-        default:
-                snd_printk(KERN_ERR "%d:%u:%d : invalid protocol version %d\n",
-                           chip->dev->devnum, fp->iface, fp->altsetting, protocol);
-                return -EINVAL;
         }
 
         return ret;
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index c166db0057d3..3ed3901369ce 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2175,7 +2175,15 @@ int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
         }
 
         host_iface = &usb_ifnum_to_if(chip->dev, ctrlif)->altsetting[0];
-        mixer->protocol = get_iface_desc(host_iface)->bInterfaceProtocol;
+        switch (get_iface_desc(host_iface)->bInterfaceProtocol) {
+        case UAC_VERSION_1:
+        default:
+                mixer->protocol = UAC_VERSION_1;
+                break;
+        case UAC_VERSION_2:
+                mixer->protocol = UAC_VERSION_2;
+                break;
+        }
 
         if ((err = snd_usb_mixer_controls(mixer)) < 0 ||
             (err = snd_usb_mixer_status_create(mixer)) < 0)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 3634cedf9306..3b5135c93062 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -173,13 +173,12 @@ int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
 
         switch (altsd->bInterfaceProtocol) {
         case UAC_VERSION_1:
+        default:
                 return init_pitch_v1(chip, iface, alts, fmt);
 
         case UAC_VERSION_2:
                 return init_pitch_v2(chip, iface, alts, fmt);
         }
-
-        return -EINVAL;
 }
 
 /*