1 files changed, 363 insertions, 393 deletions

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index b5927c3d5bc0..81b2db0edd5f 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -739,14 +739,6 @@ static int uac_mixer_unit_get_channels(struct mixer_build *state,
 				       struct uac_mixer_unit_descriptor *desc)
 {
 	int mu_channels;
-	void *c;
-
-	if (desc->bLength < sizeof(*desc))
-		return -EINVAL;
-	if (!desc->bNrInPins)
-		return -EINVAL;
-	if (desc->bLength < sizeof(*desc) + desc->bNrInPins)
-		return -EINVAL;
 
 	switch (state->mixer->protocol) {
 	case UAC_VERSION_1:
@@ -762,233 +754,254 @@ static int uac_mixer_unit_get_channels(struct mixer_build *state,
 		break;
 	}
 
-	if (!mu_channels)
-		return 0;
-
-	c = uac_mixer_unit_bmControls(desc, state->mixer->protocol);
-	if (c - (void *)desc + (mu_channels - 1) / 8 >= desc->bLength)
-		return 0; /* no bmControls -> skip */
-
 	return mu_channels;
 }
 
 /*
- * parse the source unit recursively until it reaches to a terminal
- * or a branched unit.
+ * Parse Input Terminal Unit
  */
 static int __check_input_term(struct mixer_build *state, int id,
-			    struct usb_audio_term *term)
+			      struct usb_audio_term *term);
+
+static int parse_term_uac1_iterm_unit(struct mixer_build *state,
+				      struct usb_audio_term *term,
+				      void *p1, int id)
 {
-	int protocol = state->mixer->protocol;
+	struct uac_input_terminal_descriptor *d = p1;
+
+	term->type = le16_to_cpu(d->wTerminalType);
+	term->channels = d->bNrChannels;
+	term->chconfig = le16_to_cpu(d->wChannelConfig);
+	term->name = d->iTerminal;
+	return 0;
+}
+
+static int parse_term_uac2_iterm_unit(struct mixer_build *state,
+				      struct usb_audio_term *term,
+				      void *p1, int id)
+{
+	struct uac2_input_terminal_descriptor *d = p1;
 	int err;
-	void *p1;
-	unsigned char *hdr;
 
-	memset(term, 0, sizeof(*term));
-	for (;;) {
-		/* a loop in the terminal chain? */
-		if (test_and_set_bit(id, state->termbitmap))
-			return -EINVAL;
+	/* call recursively to verify the referenced clock entity */
+	err = __check_input_term(state, d->bCSourceID, term);
+	if (err < 0)
+		return err;
 
-		p1 = find_audio_control_unit(state, id);
-		if (!p1)
-			break;
+	/* save input term properties after recursion,
+	 * to ensure they are not overriden by the recursion calls
+	 */
+	term->id = id;
+	term->type = le16_to_cpu(d->wTerminalType);
+	term->channels = d->bNrChannels;
+	term->chconfig = le32_to_cpu(d->bmChannelConfig);
+	term->name = d->iTerminal;
+	return 0;
+}
 
-		hdr = p1;
-		term->id = id;
+static int parse_term_uac3_iterm_unit(struct mixer_build *state,
+				      struct usb_audio_term *term,
+				      void *p1, int id)
+{
+	struct uac3_input_terminal_descriptor *d = p1;
+	int err;
 
-		if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
-			switch (hdr[2]) {
-			case UAC_INPUT_TERMINAL:
-				if (protocol == UAC_VERSION_1) {
-					struct uac_input_terminal_descriptor *d = p1;
-
-					term->type = le16_to_cpu(d->wTerminalType);
-					term->channels = d->bNrChannels;
-					term->chconfig = le16_to_cpu(d->wChannelConfig);
-					term->name = d->iTerminal;
-				} else { /* UAC_VERSION_2 */
-					struct uac2_input_terminal_descriptor *d = p1;
-
-					/* call recursively to verify that the
-					 * referenced clock entity is valid */
-					err = __check_input_term(state, d->bCSourceID, term);
-					if (err < 0)
-						return err;
+	/* call recursively to verify the referenced clock entity */
+	err = __check_input_term(state, d->bCSourceID, term);
+	if (err < 0)
+		return err;
 
-					/* save input term properties after recursion,
-					 * to ensure they are not overriden by the
-					 * recursion calls */
-					term->id = id;
-					term->type = le16_to_cpu(d->wTerminalType);
-					term->channels = d->bNrChannels;
-					term->chconfig = le32_to_cpu(d->bmChannelConfig);
-					term->name = d->iTerminal;
-				}
-				return 0;
-			case UAC_FEATURE_UNIT: {
-				/* the header is the same for v1 and v2 */
-				struct uac_feature_unit_descriptor *d = p1;
+	/* save input term properties after recursion,
+	 * to ensure they are not overriden by the recursion calls
+	 */
+	term->id = id;
+	term->type = le16_to_cpu(d->wTerminalType);
 
-				id = d->bSourceID;
-				break; /* continue to parse */
-			}
-			case UAC_MIXER_UNIT: {
-				struct uac_mixer_unit_descriptor *d = p1;
-
-				term->type = UAC3_MIXER_UNIT << 16; /* virtual type */
-				term->channels = uac_mixer_unit_bNrChannels(d);
-				term->chconfig = uac_mixer_unit_wChannelConfig(d, protocol);
-				term->name = uac_mixer_unit_iMixer(d);
-				return 0;
-			}
-			case UAC_SELECTOR_UNIT:
-			case UAC2_CLOCK_SELECTOR: {
-				struct uac_selector_unit_descriptor *d = p1;
-				/* call recursively to retrieve the channel info */
-				err = __check_input_term(state, d->baSourceID[0], term);
-				if (err < 0)
-					return err;
-				term->type = UAC3_SELECTOR_UNIT << 16; /* virtual type */
-				term->id = id;
-				term->name = uac_selector_unit_iSelector(d);
-				return 0;
-			}
-			case UAC1_PROCESSING_UNIT:
-			/* UAC2_EFFECT_UNIT */
-				if (protocol == UAC_VERSION_1)
-					term->type = UAC3_PROCESSING_UNIT << 16; /* virtual type */
-				else /* UAC_VERSION_2 */
-					term->type = UAC3_EFFECT_UNIT << 16; /* virtual type */
-				/* fall through */
-			case UAC1_EXTENSION_UNIT:
-			/* UAC2_PROCESSING_UNIT_V2 */
-				if (protocol == UAC_VERSION_1 && !term->type)
-					term->type = UAC3_EXTENSION_UNIT << 16; /* virtual type */
-				else if (protocol == UAC_VERSION_2 && !term->type)
-					term->type = UAC3_PROCESSING_UNIT << 16; /* virtual type */
-				/* fall through */
-			case UAC2_EXTENSION_UNIT_V2: {
-				struct uac_processing_unit_descriptor *d = p1;
-
-				if (protocol == UAC_VERSION_2 &&
-					hdr[2] == UAC2_EFFECT_UNIT) {
-					/* UAC2/UAC1 unit IDs overlap here in an
-					 * uncompatible way. Ignore this unit for now.
-					 */
-					return 0;
-				}
+	err = get_cluster_channels_v3(state, le16_to_cpu(d->wClusterDescrID));
+	if (err < 0)
+		return err;
+	term->channels = err;
 
-				if (d->bNrInPins) {
-					id = d->baSourceID[0];
-					break; /* continue to parse */
-				}
-				if (!term->type)
-					term->type = UAC3_EXTENSION_UNIT << 16; /* virtual type */
+	/* REVISIT: UAC3 IT doesn't have channels cfg */
+	term->chconfig = 0;
 
-				term->channels = uac_processing_unit_bNrChannels(d);
-				term->chconfig = uac_processing_unit_wChannelConfig(d, protocol);
-				term->name = uac_processing_unit_iProcessing(d, protocol);
-				return 0;
-			}
-			case UAC2_CLOCK_SOURCE: {
-				struct uac_clock_source_descriptor *d = p1;
+	term->name = le16_to_cpu(d->wTerminalDescrStr);
+	return 0;
+}
 
-				term->type = UAC3_CLOCK_SOURCE << 16; /* virtual type */
-				term->id = id;
-				term->name = d->iClockSource;
-				return 0;
-			}
-			default:
-				return -ENODEV;
-			}
-		} else { /* UAC_VERSION_3 */
-			switch (hdr[2]) {
-			case UAC_INPUT_TERMINAL: {
-				struct uac3_input_terminal_descriptor *d = p1;
-
-				/* call recursively to verify that the
-				 * referenced clock entity is valid */
-				err = __check_input_term(state, d->bCSourceID, term);
-				if (err < 0)
-					return err;
+static int parse_term_mixer_unit(struct mixer_build *state,
+				 struct usb_audio_term *term,
+				 void *p1, int id)
+{
+	struct uac_mixer_unit_descriptor *d = p1;
+	int protocol = state->mixer->protocol;
+	int err;
 
-				/* save input term properties after recursion,
-				 * to ensure they are not overriden by the
-				 * recursion calls */
-				term->id = id;
-				term->type = le16_to_cpu(d->wTerminalType);
+	err = uac_mixer_unit_get_channels(state, d);
+	if (err <= 0)
+		return err;
 
-				err = get_cluster_channels_v3(state, le16_to_cpu(d->wClusterDescrID));
-				if (err < 0)
-					return err;
-				term->channels = err;
+	term->type = UAC3_MIXER_UNIT << 16; /* virtual type */
+	term->channels = err;
+	if (protocol != UAC_VERSION_3) {
+		term->chconfig = uac_mixer_unit_wChannelConfig(d, protocol);
+		term->name = uac_mixer_unit_iMixer(d);
+	}
+	return 0;
+}
 
-				/* REVISIT: UAC3 IT doesn't have channels cfg */
-				term->chconfig = 0;
+static int parse_term_selector_unit(struct mixer_build *state,
+				    struct usb_audio_term *term,
+				    void *p1, int id)
+{
+	struct uac_selector_unit_descriptor *d = p1;
+	int err;
 
-				term->name = le16_to_cpu(d->wTerminalDescrStr);
-				return 0;
-			}
-			case UAC3_FEATURE_UNIT: {
-				struct uac3_feature_unit_descriptor *d = p1;
+	/* call recursively to retrieve the channel info */
+	err = __check_input_term(state, d->baSourceID[0], term);
+	if (err < 0)
+		return err;
+	term->type = UAC3_SELECTOR_UNIT << 16; /* virtual type */
+	term->id = id;
+	if (state->mixer->protocol != UAC_VERSION_3)
+		term->name = uac_selector_unit_iSelector(d);
+	return 0;
+}
 
-				id = d->bSourceID;
-				break; /* continue to parse */
-			}
-			case UAC3_CLOCK_SOURCE: {
-				struct uac3_clock_source_descriptor *d = p1;
+static int parse_term_proc_unit(struct mixer_build *state,
+				struct usb_audio_term *term,
+				void *p1, int id, int vtype)
+{
+	struct uac_processing_unit_descriptor *d = p1;
+	int protocol = state->mixer->protocol;
+	int err;
 
-				term->type = UAC3_CLOCK_SOURCE << 16; /* virtual type */
-				term->id = id;
-				term->name = le16_to_cpu(d->wClockSourceStr);
-				return 0;
-			}
-			case UAC3_MIXER_UNIT: {
-				struct uac_mixer_unit_descriptor *d = p1;
+	if (d->bNrInPins) {
+		/* call recursively to retrieve the channel info */
+		err = __check_input_term(state, d->baSourceID[0], term);
+		if (err < 0)
+			return err;
+	}
 
-				err = uac_mixer_unit_get_channels(state, d);
-				if (err <= 0)
-					return err;
+	term->type = vtype << 16; /* virtual type */
+	term->id = id;
 
-				term->channels = err;
-				term->type = UAC3_MIXER_UNIT << 16; /* virtual type */
+	if (protocol == UAC_VERSION_3)
+		return 0;
 
-				return 0;
-			}
-			case UAC3_SELECTOR_UNIT:
-			case UAC3_CLOCK_SELECTOR: {
-				struct uac_selector_unit_descriptor *d = p1;
-				/* call recursively to retrieve the channel info */
-				err = __check_input_term(state, d->baSourceID[0], term);
-				if (err < 0)
-					return err;
-				term->type = UAC3_SELECTOR_UNIT << 16; /* virtual type */
-				term->id = id;
-				term->name = 0; /* TODO: UAC3 Class-specific strings */
+	if (!term->channels) {
+		term->channels = uac_processing_unit_bNrChannels(d);
+		term->chconfig = uac_processing_unit_wChannelConfig(d, protocol);
+	}
+	term->name = uac_processing_unit_iProcessing(d, protocol);
+	return 0;
+}
 
-				return 0;
-			}
-			case UAC3_PROCESSING_UNIT: {
-				struct uac_processing_unit_descriptor *d = p1;
+static int parse_term_effect_unit(struct mixer_build *state,
+				  struct usb_audio_term *term,
+				  void *p1, int id)
+{
+	term->type = UAC3_EFFECT_UNIT << 16; /* virtual type */
+	term->id = id;
+	return 0;
+}
 
-				if (!d->bNrInPins)
-					return -EINVAL;
+static int parse_term_uac2_clock_source(struct mixer_build *state,
+					struct usb_audio_term *term,
+					void *p1, int id)
+{
+	struct uac_clock_source_descriptor *d = p1;
 
-				/* call recursively to retrieve the channel info */
-				err = __check_input_term(state, d->baSourceID[0], term);
-				if (err < 0)
-					return err;
+	term->type = UAC3_CLOCK_SOURCE << 16; /* virtual type */
+	term->id = id;
+	term->name = d->iClockSource;
+	return 0;
+}
 
-				term->type = UAC3_PROCESSING_UNIT << 16; /* virtual type */
-				term->id = id;
-				term->name = 0; /* TODO: UAC3 Class-specific strings */
+static int parse_term_uac3_clock_source(struct mixer_build *state,
+					struct usb_audio_term *term,
+					void *p1, int id)
+{
+	struct uac3_clock_source_descriptor *d = p1;
 
-				return 0;
-			}
-			default:
-				return -ENODEV;
-			}
+	term->type = UAC3_CLOCK_SOURCE << 16; /* virtual type */
+	term->id = id;
+	term->name = le16_to_cpu(d->wClockSourceStr);
+	return 0;
+}
+
+#define PTYPE(a, b)	((a) << 8 | (b))
+
+/*
+ * parse the source unit recursively until it reaches to a terminal
+ * or a branched unit.
+ */
+static int __check_input_term(struct mixer_build *state, int id,
+			      struct usb_audio_term *term)
+{
+	int protocol = state->mixer->protocol;
+	void *p1;
+	unsigned char *hdr;
+
+	for (;;) {
+		/* a loop in the terminal chain? */
+		if (test_and_set_bit(id, state->termbitmap))
+			return -EINVAL;
+
+		p1 = find_audio_control_unit(state, id);
+		if (!p1)
+			break;
+		if (!snd_usb_validate_audio_desc(p1, protocol))
+			break; /* bad descriptor */
+
+		hdr = p1;
+		term->id = id;
+
+		switch (PTYPE(protocol, hdr[2])) {
+		case PTYPE(UAC_VERSION_1, UAC_FEATURE_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC_FEATURE_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_FEATURE_UNIT): {
+			/* the header is the same for all versions */
+			struct uac_feature_unit_descriptor *d = p1;
+
+			id = d->bSourceID;
+			break; /* continue to parse */
+		}
+		case PTYPE(UAC_VERSION_1, UAC_INPUT_TERMINAL):
+			return parse_term_uac1_iterm_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_2, UAC_INPUT_TERMINAL):
+			return parse_term_uac2_iterm_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_3, UAC_INPUT_TERMINAL):
+			return parse_term_uac3_iterm_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC_MIXER_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC_MIXER_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_MIXER_UNIT):
+			return parse_term_mixer_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC_SELECTOR_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC_SELECTOR_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SELECTOR):
+		case PTYPE(UAC_VERSION_3, UAC3_SELECTOR_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SELECTOR):
+			return parse_term_selector_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC1_PROCESSING_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2):
+		case PTYPE(UAC_VERSION_3, UAC3_PROCESSING_UNIT):
+			return parse_term_proc_unit(state, term, p1, id,
+						    UAC3_PROCESSING_UNIT);
+		case PTYPE(UAC_VERSION_2, UAC2_EFFECT_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_EFFECT_UNIT):
+			return parse_term_effect_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC1_EXTENSION_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2):
+		case PTYPE(UAC_VERSION_3, UAC3_EXTENSION_UNIT):
+			return parse_term_proc_unit(state, term, p1, id,
+						    UAC3_EXTENSION_UNIT);
+		case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SOURCE):
+			return parse_term_uac2_clock_source(state, term, p1, id);
+		case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SOURCE):
+			return parse_term_uac3_clock_source(state, term, p1, id);
+		default:
+			return -ENODEV;
 		}
 	}
 	return -ENODEV;
@@ -1015,7 +1028,7 @@ struct usb_feature_control_info {
 	int type_uac2;	/* data type for uac2 if different from uac1, else -1 */
 };
 
-static struct usb_feature_control_info audio_feature_info[] = {
+static const struct usb_feature_control_info audio_feature_info[] = {
 	{ UAC_FU_MUTE,			"Mute",			USB_MIXER_INV_BOOLEAN, -1 },
 	{ UAC_FU_VOLUME,		"Volume",		USB_MIXER_S16, -1 },
 	{ UAC_FU_BASS,			"Tone Control - Bass",	USB_MIXER_S8, -1 },
@@ -1032,10 +1045,15 @@ static struct usb_feature_control_info audio_feature_info[] = {
 	{ UAC2_FU_PHASE_INVERTER,	 "Phase Inverter Control", USB_MIXER_BOOLEAN, -1 },
 };
 
+static void usb_mixer_elem_info_free(struct usb_mixer_elem_info *cval)
+{
+	kfree(cval);
+}
+
 /* private_free callback */
 void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl)
 {
-	kfree(kctl->private_data);
+	usb_mixer_elem_info_free(kctl->private_data);
 	kctl->private_data = NULL;
 }
 
@@ -1219,7 +1237,8 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
 		if (cval->min + cval->res < cval->max) {
 			int last_valid_res = cval->res;
 			int saved, test, check;
-			get_cur_mix_raw(cval, minchn, &saved);
+			if (get_cur_mix_raw(cval, minchn, &saved) < 0)
+				goto no_res_check;
 			for (;;) {
 				test = saved;
 				if (test < cval->max)
@@ -1239,6 +1258,7 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
 			snd_usb_set_cur_mix_value(cval, minchn, 0, saved);
 		}
 
+no_res_check:
 		cval->initialized = 1;
 	}
 
@@ -1433,7 +1453,7 @@ error:
 	return 0;
 }
 
-static struct snd_kcontrol_new usb_feature_unit_ctl = {
+static const struct snd_kcontrol_new usb_feature_unit_ctl = {
 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 	.name = "", /* will be filled later manually */
 	.info = mixer_ctl_feature_info,
@@ -1454,7 +1474,7 @@ static const struct snd_kcontrol_new usb_feature_unit_ctl_ro = {
  * A control which shows the boolean value from reading a UAC control on
  * the master channel.
  */
-static struct snd_kcontrol_new usb_bool_master_control_ctl_ro = {
+static const struct snd_kcontrol_new usb_bool_master_control_ctl_ro = {
 	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
 	.name = "", /* will be filled later manually */
 	.access = SNDRV_CTL_ELEM_ACCESS_READ,
@@ -1476,7 +1496,7 @@ static const struct snd_kcontrol_new usb_connector_ctl_ro = {
  * This symbol is exported in order to allow the mixer quirks to
  * hook up to the standard feature unit control mechanism
  */
-struct snd_kcontrol_new *snd_usb_feature_unit_ctl = &usb_feature_unit_ctl;
+const struct snd_kcontrol_new *snd_usb_feature_unit_ctl = &usb_feature_unit_ctl;
 
 /*
  * build a feature control
@@ -1514,7 +1534,7 @@ static void check_no_speaker_on_headset(struct snd_kcontrol *kctl,
 	strlcpy(kctl->id.name, "Headphone", sizeof(kctl->id.name));
 }
 
-static struct usb_feature_control_info *get_feature_control_info(int control)
+static const struct usb_feature_control_info *get_feature_control_info(int control)
 {
 	int i;
 
@@ -1532,7 +1552,7 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
 				struct usb_audio_term *oterm,
 				int unitid, int nameid, int readonly_mask)
 {
-	struct usb_feature_control_info *ctl_info;
+	const struct usb_feature_control_info *ctl_info;
 	unsigned int len = 0;
 	int mapped_name = 0;
 	struct snd_kcontrol *kctl;
@@ -1558,7 +1578,7 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
 
 	ctl_info = get_feature_control_info(control);
 	if (!ctl_info) {
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	if (mixer->protocol == UAC_VERSION_1)
@@ -1591,7 +1611,7 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
 
 	if (!kctl) {
 		usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	kctl->private_free = snd_usb_mixer_elem_free;
@@ -1761,7 +1781,7 @@ static void build_connector_control(struct usb_mixer_interface *mixer,
 	kctl = snd_ctl_new1(&usb_connector_ctl_ro, cval);
 	if (!kctl) {
 		usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	get_connector_control_name(mixer, term, is_input, kctl->id.name,
@@ -1782,13 +1802,6 @@ static int parse_clock_source_unit(struct mixer_build *state, int unitid,
 	if (state->mixer->protocol != UAC_VERSION_2)
 		return -EINVAL;
 
-	if (hdr->bLength != sizeof(*hdr)) {
-		usb_audio_dbg(state->chip,
-			      "Bogus clock source descriptor length of %d, ignoring.\n",
-			      hdr->bLength);
-		return 0;
-	}
-
 	/*
 	 * The only property of this unit we are interested in is the
 	 * clock source validity. If that isn't readable, just bail out.
@@ -1814,7 +1827,7 @@ static int parse_clock_source_unit(struct mixer_build *state, int unitid,
 	kctl = snd_ctl_new1(&usb_bool_master_control_ctl_ro, cval);
 
 	if (!kctl) {
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return -ENOMEM;
 	}
 
@@ -1847,62 +1860,20 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
 	__u8 *bmaControls;
 
 	if (state->mixer->protocol == UAC_VERSION_1) {
-		if (hdr->bLength < 7) {
-			usb_audio_err(state->chip,
-				      "unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
-				      unitid);
-			return -EINVAL;
-		}
 		csize = hdr->bControlSize;
-		if (!csize) {
-			usb_audio_dbg(state->chip,
-				      "unit %u: invalid bControlSize == 0\n",
-				      unitid);
-			return -EINVAL;
-		}
 		channels = (hdr->bLength - 7) / csize - 1;
 		bmaControls = hdr->bmaControls;
-		if (hdr->bLength < 7 + csize) {
-			usb_audio_err(state->chip,
-				      "unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
-				      unitid);
-			return -EINVAL;
-		}
 	} else if (state->mixer->protocol == UAC_VERSION_2) {
 		struct uac2_feature_unit_descriptor *ftr = _ftr;
-		if (hdr->bLength < 6) {
-			usb_audio_err(state->chip,
-				      "unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
-				      unitid);
-			return -EINVAL;
-		}
 		csize = 4;
 		channels = (hdr->bLength - 6) / 4 - 1;
 		bmaControls = ftr->bmaControls;
-		if (hdr->bLength < 6 + csize) {
-			usb_audio_err(state->chip,
-				      "unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
-				      unitid);
-			return -EINVAL;
-		}
 	} else { /* UAC_VERSION_3 */
 		struct uac3_feature_unit_descriptor *ftr = _ftr;
 
-		if (hdr->bLength < 7) {
-			usb_audio_err(state->chip,
-				      "unit %u: invalid UAC3_FEATURE_UNIT descriptor\n",
-				      unitid);
-			return -EINVAL;
-		}
 		csize = 4;
 		channels = (ftr->bLength - 7) / 4 - 1;
 		bmaControls = ftr->bmaControls;
-		if (hdr->bLength < 7 + csize) {
-			usb_audio_err(state->chip,
-				      "unit %u: invalid UAC3_FEATURE_UNIT descriptor\n",
-				      unitid);
-			return -EINVAL;
-		}
 	}
 
 	/* parse the source unit */
@@ -2009,6 +1980,31 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
  * Mixer Unit
  */
 
+/* check whether the given in/out overflows bmMixerControls matrix */
+static bool mixer_bitmap_overflow(struct uac_mixer_unit_descriptor *desc,
+				  int protocol, int num_ins, int num_outs)
+{
+	u8 *hdr = (u8 *)desc;
+	u8 *c = uac_mixer_unit_bmControls(desc, protocol);
+	size_t rest; /* remaining bytes after bmMixerControls */
+
+	switch (protocol) {
+	case UAC_VERSION_1:
+	default:
+		rest = 1; /* iMixer */
+		break;
+	case UAC_VERSION_2:
+		rest = 2; /* bmControls + iMixer */
+		break;
+	case UAC_VERSION_3:
+		rest = 6; /* bmControls + wMixerDescrStr */
+		break;
+	}
+
+	/* overflow? */
+	return c + (num_ins * num_outs + 7) / 8 + rest > hdr + hdr[0];
+}
+
 /*
  * build a mixer unit control
  *
@@ -2051,7 +2047,7 @@ static void build_mixer_unit_ctl(struct mixer_build *state,
 	kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
 	if (!kctl) {
 		usb_audio_err(state->chip, "cannot malloc kcontrol\n");
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		return;
 	}
 	kctl->private_free = snd_usb_mixer_elem_free;
@@ -2077,15 +2073,11 @@ static int parse_audio_input_terminal(struct mixer_build *state, int unitid,
 
 	if (state->mixer->protocol == UAC_VERSION_2) {
 		struct uac2_input_terminal_descriptor *d_v2 = raw_desc;
-		if (d_v2->bLength < sizeof(*d_v2))
-			return -EINVAL;
 		control = UAC2_TE_CONNECTOR;
 		term_id = d_v2->bTerminalID;
 		bmctls = le16_to_cpu(d_v2->bmControls);
 	} else if (state->mixer->protocol == UAC_VERSION_3) {
 		struct uac3_input_terminal_descriptor *d_v3 = raw_desc;
-		if (d_v3->bLength < sizeof(*d_v3))
-			return -EINVAL;
 		control = UAC3_TE_INSERTION;
 		term_id = d_v3->bTerminalID;
 		bmctls = le32_to_cpu(d_v3->bmControls);
@@ -2137,6 +2129,9 @@ static int parse_audio_mixer_unit(struct mixer_build *state, int unitid,
 		if (err < 0)
 			return err;
 		num_ins += iterm.channels;
+		if (mixer_bitmap_overflow(desc, state->mixer->protocol,
+					  num_ins, num_outs))
+			break;
 		for (; ich < num_ins; ich++) {
 			int och, ich_has_controls = 0;
 
@@ -2211,7 +2206,7 @@ static const struct snd_kcontrol_new mixer_procunit_ctl = {
  */
 struct procunit_value_info {
 	int control;
-	char *suffix;
+	const char *suffix;
 	int val_type;
 	int min_value;
 };
@@ -2219,44 +2214,44 @@ struct procunit_value_info {
 struct procunit_info {
 	int type;
 	char *name;
-	struct procunit_value_info *values;
+	const struct procunit_value_info *values;
 };
 
-static struct procunit_value_info undefined_proc_info[] = {
+static const struct procunit_value_info undefined_proc_info[] = {
 	{ 0x00, "Control Undefined", 0 },
 	{ 0 }
 };
 
-static struct procunit_value_info updown_proc_info[] = {
+static const struct procunit_value_info updown_proc_info[] = {
 	{ UAC_UD_ENABLE, "Switch", USB_MIXER_BOOLEAN },
 	{ UAC_UD_MODE_SELECT, "Mode Select", USB_MIXER_U8, 1 },
 	{ 0 }
 };
-static struct procunit_value_info prologic_proc_info[] = {
+static const struct procunit_value_info prologic_proc_info[] = {
 	{ UAC_DP_ENABLE, "Switch", USB_MIXER_BOOLEAN },
 	{ UAC_DP_MODE_SELECT, "Mode Select", USB_MIXER_U8, 1 },
 	{ 0 }
 };
-static struct procunit_value_info threed_enh_proc_info[] = {
+static const struct procunit_value_info threed_enh_proc_info[] = {
 	{ UAC_3D_ENABLE, "Switch", USB_MIXER_BOOLEAN },
 	{ UAC_3D_SPACE, "Spaciousness", USB_MIXER_U8 },
 	{ 0 }
 };
-static struct procunit_value_info reverb_proc_info[] = {
+static const struct procunit_value_info reverb_proc_info[] = {
 	{ UAC_REVERB_ENABLE, "Switch", USB_MIXER_BOOLEAN },
 	{ UAC_REVERB_LEVEL, "Level", USB_MIXER_U8 },
 	{ UAC_REVERB_TIME, "Time", USB_MIXER_U16 },
 	{ UAC_REVERB_FEEDBACK, "Feedback", USB_MIXER_U8 },
 	{ 0 }
 };
-static struct procunit_value_info chorus_proc_info[] = {
+static const struct procunit_value_info chorus_proc_info[] = {
 	{ UAC_CHORUS_ENABLE, "Switch", USB_MIXER_BOOLEAN },
 	{ UAC_CHORUS_LEVEL, "Level", USB_MIXER_U8 },
 	{ UAC_CHORUS_RATE, "Rate", USB_MIXER_U16 },
 	{ UAC_CHORUS_DEPTH, "Depth", USB_MIXER_U16 },
 	{ 0 }
 };
-static struct procunit_value_info dcr_proc_info[] = {
+static const struct procunit_value_info dcr_proc_info[] = {
 	{ UAC_DCR_ENABLE, "Switch", USB_MIXER_BOOLEAN },
 	{ UAC_DCR_RATE, "Ratio", USB_MIXER_U16 },
 	{ UAC_DCR_MAXAMPL, "Max Amp", USB_MIXER_S16 },
@@ -2266,7 +2261,7 @@ static struct procunit_value_info dcr_proc_info[] = {
 	{ 0 }
 };
 
-static struct procunit_info procunits[] = {
+static const struct procunit_info procunits[] = {
 	{ UAC_PROCESS_UP_DOWNMIX, "Up Down", updown_proc_info },
 	{ UAC_PROCESS_DOLBY_PROLOGIC, "Dolby Prologic", prologic_proc_info },
 	{ UAC_PROCESS_STEREO_EXTENDER, "3D Stereo Extender", threed_enh_proc_info },
@@ -2276,16 +2271,16 @@ static struct procunit_info procunits[] = {
 	{ 0 },
 };
 
-static struct procunit_value_info uac3_updown_proc_info[] = {
+static const struct procunit_value_info uac3_updown_proc_info[] = {
 	{ UAC3_UD_MODE_SELECT, "Mode Select", USB_MIXER_U8, 1 },
 	{ 0 }
 };
-static struct procunit_value_info uac3_stereo_ext_proc_info[] = {
+static const struct procunit_value_info uac3_stereo_ext_proc_info[] = {
 	{ UAC3_EXT_WIDTH_CONTROL, "Width Control", USB_MIXER_U8 },
 	{ 0 }
 };
 
-static struct procunit_info uac3_procunits[] = {
+static const struct procunit_info uac3_procunits[] = {
 	{ UAC3_PROCESS_UP_DOWNMIX, "Up Down", uac3_updown_proc_info },
 	{ UAC3_PROCESS_STEREO_EXTENDER, "3D Stereo Extender", uac3_stereo_ext_proc_info },
 	{ UAC3_PROCESS_MULTI_FUNCTION, "Multi-Function", undefined_proc_info },
@@ -2295,23 +2290,23 @@ static struct procunit_info uac3_procunits[] = {
 /*
  * predefined data for extension units
  */
-static struct procunit_value_info clock_rate_xu_info[] = {
+static const struct procunit_value_info clock_rate_xu_info[] = {
 	{ USB_XU_CLOCK_RATE_SELECTOR, "Selector", USB_MIXER_U8, 0 },
 	{ 0 }
 };
-static struct procunit_value_info clock_source_xu_info[] = {
+static const struct procunit_value_info clock_source_xu_info[] = {
 	{ USB_XU_CLOCK_SOURCE_SELECTOR, "External", USB_MIXER_BOOLEAN },
 	{ 0 }
 };
-static struct procunit_value_info spdif_format_xu_info[] = {
+static const struct procunit_value_info spdif_format_xu_info[] = {
 	{ USB_XU_DIGITAL_FORMAT_SELECTOR, "SPDIF/AC3", USB_MIXER_BOOLEAN },
 	{ 0 }
 };
-static struct procunit_value_info soft_limit_xu_info[] = {
+static const struct procunit_value_info soft_limit_xu_info[] = {
 	{ USB_XU_SOFT_LIMIT_SELECTOR, " ", USB_MIXER_BOOLEAN },
 	{ 0 }
 };
-static struct procunit_info extunits[] = {
+static const struct procunit_info extunits[] = {
 	{ USB_XU_CLOCK_RATE, "Clock rate", clock_rate_xu_info },
 	{ USB_XU_CLOCK_SOURCE, "DigitalIn CLK source", clock_source_xu_info },
 	{ USB_XU_DIGITAL_IO_STATUS, "DigitalOut format:", spdif_format_xu_info },
@@ -2323,7 +2318,7 @@ static struct procunit_info extunits[] = {
  * build a processing/extension unit
  */
 static int build_audio_procunit(struct mixer_build *state, int unitid,
-				void *raw_desc, struct procunit_info *list,
+				void *raw_desc, const struct procunit_info *list,
 				bool extension_unit)
 {
 	struct uac_processing_unit_descriptor *desc = raw_desc;
@@ -2331,31 +2326,20 @@ static int build_audio_procunit(struct mixer_build *state, int unitid,
 	struct usb_mixer_elem_info *cval;
 	struct snd_kcontrol *kctl;
 	int i, err, nameid, type, len;
-	struct procunit_info *info;
-	struct procunit_value_info *valinfo;
+	const struct procunit_info *info;
+	const struct procunit_value_info *valinfo;
 	const struct usbmix_name_map *map;
-	static struct procunit_value_info default_value_info[] = {
+	static const struct procunit_value_info default_value_info[] = {
 		{ 0x01, "Switch", USB_MIXER_BOOLEAN },
 		{ 0 }
 	};
-	static struct procunit_info default_info = {
+	static const struct procunit_info default_info = {
 		0, NULL, default_value_info
 	};
 	const char *name = extension_unit ?
 		"Extension Unit" : "Processing Unit";
 
-	if (desc->bLength < 13) {
-		usb_audio_err(state->chip, "invalid %s descriptor (id %d)\n", name, unitid);
-		return -EINVAL;
-	}
-
 	num_ins = desc->bNrInPins;
-	if (desc->bLength < 13 + num_ins ||
-	    desc->bLength < num_ins + uac_processing_unit_bControlSize(desc, state->mixer->protocol)) {
-		usb_audio_err(state->chip, "invalid %s descriptor (id %d)\n", name, unitid);
-		return -EINVAL;
-	}
-
 	for (i = 0; i < num_ins; i++) {
 		err = parse_audio_unit(state, desc->baSourceID[i]);
 		if (err < 0)
@@ -2446,7 +2430,7 @@ static int build_audio_procunit(struct mixer_build *state, int unitid,
 
 		kctl = snd_ctl_new1(&mixer_procunit_ctl, cval);
 		if (!kctl) {
-			kfree(cval);
+			usb_mixer_elem_info_free(cval);
 			return -ENOMEM;
 		}
 		kctl->private_free = snd_usb_mixer_elem_free;
@@ -2584,7 +2568,7 @@ static void usb_mixer_selector_elem_free(struct snd_kcontrol *kctl)
 	if (kctl->private_data) {
 		struct usb_mixer_elem_info *cval = kctl->private_data;
 		num_ins = cval->max;
-		kfree(cval);
+		usb_mixer_elem_info_free(cval);
 		kctl->private_data = NULL;
 	}
 	if (kctl->private_value) {
@@ -2610,13 +2594,6 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	const struct usbmix_name_map *map;
 	char **namelist;
 
-	if (desc->bLength < 5 || !desc->bNrInPins ||
-	    desc->bLength < 5 + desc->bNrInPins) {
-		usb_audio_err(state->chip,
-			"invalid SELECTOR UNIT descriptor %d\n", unitid);
-		return -EINVAL;
-	}
-
 	for (i = 0; i < desc->bNrInPins; i++) {
 		err = parse_audio_unit(state, desc->baSourceID[i]);
 		if (err < 0)
@@ -2656,10 +2633,10 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 		break;
 	}
 
-	namelist = kmalloc_array(desc->bNrInPins, sizeof(char *), GFP_KERNEL);
+	namelist = kcalloc(desc->bNrInPins, sizeof(char *), GFP_KERNEL);
 	if (!namelist) {
-		kfree(cval);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto error_cval;
 	}
 #define MAX_ITEM_NAME_LEN	64
 	for (i = 0; i < desc->bNrInPins; i++) {
@@ -2667,11 +2644,8 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 		len = 0;
 		namelist[i] = kmalloc(MAX_ITEM_NAME_LEN, GFP_KERNEL);
 		if (!namelist[i]) {
-			while (i--)
-				kfree(namelist[i]);
-			kfree(namelist);
-			kfree(cval);
-			return -ENOMEM;
+			err = -ENOMEM;
+			goto error_name;
 		}
 		len = check_mapped_selector_name(state, unitid, i, namelist[i],
 						 MAX_ITEM_NAME_LEN);
@@ -2685,11 +2659,8 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	kctl = snd_ctl_new1(&mixer_selectunit_ctl, cval);
 	if (! kctl) {
 		usb_audio_err(state->chip, "cannot malloc kcontrol\n");
-		for (i = 0; i < desc->bNrInPins; i++)
-			kfree(namelist[i]);
-		kfree(namelist);
-		kfree(cval);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto error_name;
 	}
 	kctl->private_value = (unsigned long)namelist;
 	kctl->private_free = usb_mixer_selector_elem_free;
@@ -2735,6 +2706,14 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	usb_audio_dbg(state->chip, "[%d] SU [%s] items = %d\n",
 		    cval->head.id, kctl->id.name, desc->bNrInPins);
 	return snd_usb_mixer_add_control(&cval->head, kctl);
+
+ error_name:
+	for (i = 0; i < desc->bNrInPins; i++)
+		kfree(namelist[i]);
+	kfree(namelist);
+ error_cval:
+	usb_mixer_elem_info_free(cval);
+	return err;
 }
 
 /*
@@ -2755,62 +2734,49 @@ static int parse_audio_unit(struct mixer_build *state, int unitid)
 		return -EINVAL;
 	}
 
-	if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
-		switch (p1[2]) {
-		case UAC_INPUT_TERMINAL:
-			return parse_audio_input_terminal(state, unitid, p1);
-		case UAC_MIXER_UNIT:
-			return parse_audio_mixer_unit(state, unitid, p1);
-		case UAC2_CLOCK_SOURCE:
-			return parse_clock_source_unit(state, unitid, p1);
-		case UAC_SELECTOR_UNIT:
-		case UAC2_CLOCK_SELECTOR:
-			return parse_audio_selector_unit(state, unitid, p1);
-		case UAC_FEATURE_UNIT:
-			return parse_audio_feature_unit(state, unitid, p1);
-		case UAC1_PROCESSING_UNIT:
-		/*   UAC2_EFFECT_UNIT has the same value */
-			if (protocol == UAC_VERSION_1)
-				return parse_audio_processing_unit(state, unitid, p1);
-			else
-				return 0; /* FIXME - effect units not implemented yet */
-		case UAC1_EXTENSION_UNIT:
-		/*   UAC2_PROCESSING_UNIT_V2 has the same value */
-			if (protocol == UAC_VERSION_1)
-				return parse_audio_extension_unit(state, unitid, p1);
-			else /* UAC_VERSION_2 */
-				return parse_audio_processing_unit(state, unitid, p1);
-		case UAC2_EXTENSION_UNIT_V2:
-			return parse_audio_extension_unit(state, unitid, p1);
-		default:
-			usb_audio_err(state->chip,
-				"unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
-			return -EINVAL;
-		}
-	} else { /* UAC_VERSION_3 */
-		switch (p1[2]) {
-		case UAC_INPUT_TERMINAL:
-			return parse_audio_input_terminal(state, unitid, p1);
-		case UAC3_MIXER_UNIT:
-			return parse_audio_mixer_unit(state, unitid, p1);
-		case UAC3_CLOCK_SOURCE:
-			return parse_clock_source_unit(state, unitid, p1);
-		case UAC3_SELECTOR_UNIT:
-		case UAC3_CLOCK_SELECTOR:
-			return parse_audio_selector_unit(state, unitid, p1);
-		case UAC3_FEATURE_UNIT:
-			return parse_audio_feature_unit(state, unitid, p1);
-		case UAC3_EFFECT_UNIT:
-			return 0; /* FIXME - effect units not implemented yet */
-		case UAC3_PROCESSING_UNIT:
-			return parse_audio_processing_unit(state, unitid, p1);
-		case UAC3_EXTENSION_UNIT:
-			return parse_audio_extension_unit(state, unitid, p1);
-		default:
-			usb_audio_err(state->chip,
-				"unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
-			return -EINVAL;
-		}
+	if (!snd_usb_validate_audio_desc(p1, protocol)) {
+		usb_audio_dbg(state->chip, "invalid unit %d\n", unitid);
+		return 0; /* skip invalid unit */
+	}
+
+	switch (PTYPE(protocol, p1[2])) {
+	case PTYPE(UAC_VERSION_1, UAC_INPUT_TERMINAL):
+	case PTYPE(UAC_VERSION_2, UAC_INPUT_TERMINAL):
+	case PTYPE(UAC_VERSION_3, UAC_INPUT_TERMINAL):
+		return parse_audio_input_terminal(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC_MIXER_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC_MIXER_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_MIXER_UNIT):
+		return parse_audio_mixer_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SOURCE):
+	case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SOURCE):
+		return parse_clock_source_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC_SELECTOR_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC_SELECTOR_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_SELECTOR_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SELECTOR):
+	case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SELECTOR):
+		return parse_audio_selector_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC_FEATURE_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC_FEATURE_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_FEATURE_UNIT):
+		return parse_audio_feature_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC1_PROCESSING_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2):
+	case PTYPE(UAC_VERSION_3, UAC3_PROCESSING_UNIT):
+		return parse_audio_processing_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC1_EXTENSION_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2):
+	case PTYPE(UAC_VERSION_3, UAC3_EXTENSION_UNIT):
+		return parse_audio_extension_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_2, UAC2_EFFECT_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_EFFECT_UNIT):
+		return 0; /* FIXME - effect units not implemented yet */
+	default:
+		usb_audio_err(state->chip,
+			      "unit %u: unexpected type 0x%02x\n",
+			      unitid, p1[2]);
+		return -EINVAL;
 	}
 }
 
@@ -2845,7 +2811,7 @@ struct uac3_badd_profile {
 	int st_chmask;	/* side tone mixing channel mask */
 };
 
-static struct uac3_badd_profile uac3_badd_profiles[] = {
+static const struct uac3_badd_profile uac3_badd_profiles[] = {
 	{
 		/*
 		 * BAIF, BAOF or combination of both
@@ -2906,7 +2872,7 @@ static struct uac3_badd_profile uac3_badd_profiles[] = {
 };
 
 static bool uac3_badd_func_has_valid_channels(struct usb_mixer_interface *mixer,
-					      struct uac3_badd_profile *f,
+					      const struct uac3_badd_profile *f,
 					      int c_chmask, int p_chmask)
 {
 	/*
@@ -2950,7 +2916,7 @@ static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer,
 	struct usb_device *dev = mixer->chip->dev;
 	struct usb_interface_assoc_descriptor *assoc;
 	int badd_profile = mixer->chip->badd_profile;
-	struct uac3_badd_profile *f;
+	const struct uac3_badd_profile *f;
 	const struct usbmix_ctl_map *map;
 	int p_chmask = 0, c_chmask = 0, st_chmask = 0;
 	int i;
@@ -2972,6 +2938,9 @@ static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer,
 			continue;
 
 		iface = usb_ifnum_to_if(dev, intf);
+		if (!iface)
+			continue;
+
 		num = iface->num_altsetting;
 
 		if (num < 2)
@@ -3125,11 +3094,12 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 	while ((p = snd_usb_find_csint_desc(mixer->hostif->extra,
 					    mixer->hostif->extralen,
 					    p, UAC_OUTPUT_TERMINAL)) != NULL) {
+		if (!snd_usb_validate_audio_desc(p, mixer->protocol))
+			continue; /* skip invalid descriptor */
+
 		if (mixer->protocol == UAC_VERSION_1) {
 			struct uac1_output_terminal_descriptor *desc = p;
 
-			if (desc->bLength < sizeof(*desc))
-				continue; /* invalid descriptor? */
 			/* mark terminal ID as visited */
 			set_bit(desc->bTerminalID, state.unitbitmap);
 			state.oterm.id = desc->bTerminalID;
@@ -3141,8 +3111,6 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 		} else if (mixer->protocol == UAC_VERSION_2) {
 			struct uac2_output_terminal_descriptor *desc = p;
 
-			if (desc->bLength < sizeof(*desc))
-				continue; /* invalid descriptor? */
 			/* mark terminal ID as visited */
 			set_bit(desc->bTerminalID, state.unitbitmap);
 			state.oterm.id = desc->bTerminalID;
@@ -3168,8 +3136,6 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
 		} else {  /* UAC_VERSION_3 */
 			struct uac3_output_terminal_descriptor *desc = p;
 
-			if (desc->bLength < sizeof(*desc))
-				continue; /* invalid descriptor? */
 			/* mark terminal ID as visited */
 			set_bit(desc->bTerminalID, state.unitbitmap);
 			state.oterm.id = desc->bTerminalID;
@@ -3216,7 +3182,7 @@ static void snd_usb_mixer_dump_cval(struct snd_info_buffer *buffer,
 				    struct usb_mixer_elem_list *list)
 {
 	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
-	static char *val_types[] = {"BOOLEAN", "INV_BOOLEAN",
+	static const char * const val_types[] = {"BOOLEAN", "INV_BOOLEAN",
 				    "S8", "U8", "S16", "U16"};
 	snd_iprintf(buffer, "    Info: id=%i, control=%i, cmask=0x%x, "
 			    "channels=%i, type=\"%s\"\n", cval->head.id,
@@ -3449,7 +3415,7 @@ static int create_keep_iface_ctl(struct usb_mixer_interface *mixer)
 int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
 			 int ignore_error)
 {
-	static struct snd_device_ops dev_ops = {
+	static const struct snd_device_ops dev_ops = {
 		.dev_free = snd_usb_mixer_dev_free
 	};
 	struct usb_mixer_interface *mixer;
@@ -3530,6 +3496,8 @@ void snd_usb_mixer_disconnect(struct usb_mixer_interface *mixer)
 		usb_kill_urb(mixer->urb);
 	if (mixer->rc_urb)
 		usb_kill_urb(mixer->rc_urb);
+	if (mixer->private_free)
+		mixer->private_free(mixer);
 	mixer->disconnected = true;
 }
 
@@ -3557,6 +3525,8 @@ static int snd_usb_mixer_activate(struct usb_mixer_interface *mixer)
 int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer)
 {
 	snd_usb_mixer_inactivate(mixer);
+	if (mixer->private_suspend)
+		mixer->private_suspend(mixer);
 	return 0;
 }