Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2009 insertions, 0 deletions

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
new file mode 100644
index 000000000..3bb89fcaa
--- /dev/null
+++ b/sound/usb/mixer_quirks.c
@@ -0,0 +1,2009 @@
+/*
+ *   USB Audio Driver for ALSA
+ *
+ *   Quirks and vendor-specific extensions for mixer interfaces
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
+ *
+ *   Audio Advantage Micro II support added by:
+ *	    Przemek Rudy (prudy1@o2.pl)
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/hid.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+
+#include <sound/asoundef.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/hwdep.h>
+#include <sound/info.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "mixer_quirks.h"
+#include "mixer_scarlett.h"
+#include "mixer_us16x08.h"
+#include "helper.h"
+
+struct std_mono_table {
+	unsigned int unitid, control, cmask;
+	int val_type;
+	const char *name;
+	snd_kcontrol_tlv_rw_t *tlv_callback;
+};
+
+/* This function allows for the creation of standard UAC controls.
+ * See the quirks for M-Audio FTUs or Ebox-44.
+ * If you don't want to set a TLV callback pass NULL.
+ *
+ * Since there doesn't seem to be a devices that needs a multichannel
+ * version, we keep it mono for simplicity.
+ */
+static int snd_create_std_mono_ctl_offset(struct usb_mixer_interface *mixer,
+				unsigned int unitid,
+				unsigned int control,
+				unsigned int cmask,
+				int val_type,
+				unsigned int idx_off,
+				const char *name,
+				snd_kcontrol_tlv_rw_t *tlv_callback)
+{
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+
+	cval = kzalloc(sizeof(*cval), GFP_KERNEL);
+	if (!cval)
+		return -ENOMEM;
+
+	snd_usb_mixer_elem_init_std(&cval->head, mixer, unitid);
+	cval->val_type = val_type;
+	cval->channels = 1;
+	cval->control = control;
+	cval->cmask = cmask;
+	cval->idx_off = idx_off;
+
+	/* get_min_max() is called only for integer volumes later,
+	 * so provide a short-cut for booleans */
+	cval->min = 0;
+	cval->max = 1;
+	cval->res = 0;
+	cval->dBmin = 0;
+	cval->dBmax = 0;
+
+	/* Create control */
+	kctl = snd_ctl_new1(snd_usb_feature_unit_ctl, cval);
+	if (!kctl) {
+		kfree(cval);
+		return -ENOMEM;
+	}
+
+	/* Set name */
+	snprintf(kctl->id.name, sizeof(kctl->id.name), name);
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	/* set TLV */
+	if (tlv_callback) {
+		kctl->tlv.c = tlv_callback;
+		kctl->vd[0].access |=
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+	}
+	/* Add control to mixer */
+	return snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static int snd_create_std_mono_ctl(struct usb_mixer_interface *mixer,
+				unsigned int unitid,
+				unsigned int control,
+				unsigned int cmask,
+				int val_type,
+				const char *name,
+				snd_kcontrol_tlv_rw_t *tlv_callback)
+{
+	return snd_create_std_mono_ctl_offset(mixer, unitid, control, cmask,
+		val_type, 0 /* Offset */, name, tlv_callback);
+}
+
+/*
+ * Create a set of standard UAC controls from a table
+ */
+static int snd_create_std_mono_table(struct usb_mixer_interface *mixer,
+				     const struct std_mono_table *t)
+{
+	int err;
+
+	while (t->name != NULL) {
+		err = snd_create_std_mono_ctl(mixer, t->unitid, t->control,
+				t->cmask, t->val_type, t->name, t->tlv_callback);
+		if (err < 0)
+			return err;
+		t++;
+	}
+
+	return 0;
+}
+
+static int add_single_ctl_with_resume(struct usb_mixer_interface *mixer,
+				      int id,
+				      usb_mixer_elem_resume_func_t resume,
+				      const struct snd_kcontrol_new *knew,
+				      struct usb_mixer_elem_list **listp)
+{
+	struct usb_mixer_elem_list *list;
+	struct snd_kcontrol *kctl;
+
+	list = kzalloc(sizeof(*list), GFP_KERNEL);
+	if (!list)
+		return -ENOMEM;
+	if (listp)
+		*listp = list;
+	list->mixer = mixer;
+	list->id = id;
+	list->resume = resume;
+	kctl = snd_ctl_new1(knew, list);
+	if (!kctl) {
+		kfree(list);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+	/* don't use snd_usb_mixer_add_control() here, this is a special list element */
+	return snd_usb_mixer_add_list(list, kctl, false);
+}
+
+/*
+ * Sound Blaster remote control configuration
+ *
+ * format of remote control data:
+ * Extigy:       xx 00
+ * Audigy 2 NX:  06 80 xx 00 00 00
+ * Live! 24-bit: 06 80 xx yy 22 83
+ */
+static const struct rc_config {
+	u32 usb_id;
+	u8  offset;
+	u8  length;
+	u8  packet_length;
+	u8  min_packet_length; /* minimum accepted length of the URB result */
+	u8  mute_mixer_id;
+	u32 mute_code;
+} rc_configs[] = {
+	{ USB_ID(0x041e, 0x3000), 0, 1, 2, 1,  18, 0x0013 }, /* Extigy       */
+	{ USB_ID(0x041e, 0x3020), 2, 1, 6, 6,  18, 0x0013 }, /* Audigy 2 NX  */
+	{ USB_ID(0x041e, 0x3040), 2, 2, 6, 6,  2,  0x6e91 }, /* Live! 24-bit */
+	{ USB_ID(0x041e, 0x3042), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 */
+	{ USB_ID(0x041e, 0x30df), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 Pro */
+	{ USB_ID(0x041e, 0x3237), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 Pro */
+	{ USB_ID(0x041e, 0x3263), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 Pro */
+	{ USB_ID(0x041e, 0x3048), 2, 2, 6, 6,  2,  0x6e91 }, /* Toshiba SB0500 */
+};
+
+static void snd_usb_soundblaster_remote_complete(struct urb *urb)
+{
+	struct usb_mixer_interface *mixer = urb->context;
+	const struct rc_config *rc = mixer->rc_cfg;
+	u32 code;
+
+	if (urb->status < 0 || urb->actual_length < rc->min_packet_length)
+		return;
+
+	code = mixer->rc_buffer[rc->offset];
+	if (rc->length == 2)
+		code |= mixer->rc_buffer[rc->offset + 1] << 8;
+
+	/* the Mute button actually changes the mixer control */
+	if (code == rc->mute_code)
+		snd_usb_mixer_notify_id(mixer, rc->mute_mixer_id);
+	mixer->rc_code = code;
+	wmb();
+	wake_up(&mixer->rc_waitq);
+}
+
+static long snd_usb_sbrc_hwdep_read(struct snd_hwdep *hw, char __user *buf,
+				     long count, loff_t *offset)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	int err;
+	u32 rc_code;
+
+	if (count != 1 && count != 4)
+		return -EINVAL;
+	err = wait_event_interruptible(mixer->rc_waitq,
+				       (rc_code = xchg(&mixer->rc_code, 0)) != 0);
+	if (err == 0) {
+		if (count == 1)
+			err = put_user(rc_code, buf);
+		else
+			err = put_user(rc_code, (u32 __user *)buf);
+	}
+	return err < 0 ? err : count;
+}
+
+static __poll_t snd_usb_sbrc_hwdep_poll(struct snd_hwdep *hw, struct file *file,
+					    poll_table *wait)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+
+	poll_wait(file, &mixer->rc_waitq, wait);
+	return mixer->rc_code ? EPOLLIN | EPOLLRDNORM : 0;
+}
+
+static int snd_usb_soundblaster_remote_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_hwdep *hwdep;
+	int err, len, i;
+
+	for (i = 0; i < ARRAY_SIZE(rc_configs); ++i)
+		if (rc_configs[i].usb_id == mixer->chip->usb_id)
+			break;
+	if (i >= ARRAY_SIZE(rc_configs))
+		return 0;
+	mixer->rc_cfg = &rc_configs[i];
+
+	len = mixer->rc_cfg->packet_length;
+
+	init_waitqueue_head(&mixer->rc_waitq);
+	err = snd_hwdep_new(mixer->chip->card, "SB remote control", 0, &hwdep);
+	if (err < 0)
+		return err;
+	snprintf(hwdep->name, sizeof(hwdep->name),
+		 "%s remote control", mixer->chip->card->shortname);
+	hwdep->iface = SNDRV_HWDEP_IFACE_SB_RC;
+	hwdep->private_data = mixer;
+	hwdep->ops.read = snd_usb_sbrc_hwdep_read;
+	hwdep->ops.poll = snd_usb_sbrc_hwdep_poll;
+	hwdep->exclusive = 1;
+
+	mixer->rc_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!mixer->rc_urb)
+		return -ENOMEM;
+	mixer->rc_setup_packet = kmalloc(sizeof(*mixer->rc_setup_packet), GFP_KERNEL);
+	if (!mixer->rc_setup_packet) {
+		usb_free_urb(mixer->rc_urb);
+		mixer->rc_urb = NULL;
+		return -ENOMEM;
+	}
+	mixer->rc_setup_packet->bRequestType =
+		USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+	mixer->rc_setup_packet->bRequest = UAC_GET_MEM;
+	mixer->rc_setup_packet->wValue = cpu_to_le16(0);
+	mixer->rc_setup_packet->wIndex = cpu_to_le16(0);
+	mixer->rc_setup_packet->wLength = cpu_to_le16(len);
+	usb_fill_control_urb(mixer->rc_urb, mixer->chip->dev,
+			     usb_rcvctrlpipe(mixer->chip->dev, 0),
+			     (u8*)mixer->rc_setup_packet, mixer->rc_buffer, len,
+			     snd_usb_soundblaster_remote_complete, mixer);
+	return 0;
+}
+
+#define snd_audigy2nx_led_info		snd_ctl_boolean_mono_info
+
+static int snd_audigy2nx_led_get(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value >> 8;
+	return 0;
+}
+
+static int snd_audigy2nx_led_update(struct usb_mixer_interface *mixer,
+				    int value, int index)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	if (chip->usb_id == USB_ID(0x041e, 0x3042))
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x24,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      !value, 0, NULL, 0);
+	/* USB X-Fi S51 Pro */
+	if (chip->usb_id == USB_ID(0x041e, 0x30df))
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x24,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      !value, 0, NULL, 0);
+	else
+		err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x24,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      value, index + 2, NULL, 0);
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int index = kcontrol->private_value & 0xff;
+	unsigned int value = ucontrol->value.integer.value[0];
+	int old_value = kcontrol->private_value >> 8;
+	int err;
+
+	if (value > 1)
+		return -EINVAL;
+	if (value == old_value)
+		return 0;
+	kcontrol->private_value = (value << 8) | index;
+	err = snd_audigy2nx_led_update(mixer, value, index);
+	return err < 0 ? err : 1;
+}
+
+static int snd_audigy2nx_led_resume(struct usb_mixer_elem_list *list)
+{
+	int priv_value = list->kctl->private_value;
+
+	return snd_audigy2nx_led_update(list->mixer, priv_value >> 8,
+					priv_value & 0xff);
+}
+
+/* name and private_value are set dynamically */
+static const struct snd_kcontrol_new snd_audigy2nx_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.info = snd_audigy2nx_led_info,
+	.get = snd_audigy2nx_led_get,
+	.put = snd_audigy2nx_led_put,
+};
+
+static const char * const snd_audigy2nx_led_names[] = {
+	"CMSS LED Switch",
+	"Power LED Switch",
+	"Dolby Digital LED Switch",
+};
+
+static int snd_audigy2nx_controls_create(struct usb_mixer_interface *mixer)
+{
+	int i, err;
+
+	for (i = 0; i < ARRAY_SIZE(snd_audigy2nx_led_names); ++i) {
+		struct snd_kcontrol_new knew;
+
+		/* USB X-Fi S51 doesn't have a CMSS LED */
+		if ((mixer->chip->usb_id == USB_ID(0x041e, 0x3042)) && i == 0)
+			continue;
+		/* USB X-Fi S51 Pro doesn't have one either */
+		if ((mixer->chip->usb_id == USB_ID(0x041e, 0x30df)) && i == 0)
+			continue;
+		if (i > 1 && /* Live24ext has 2 LEDs only */
+			(mixer->chip->usb_id == USB_ID(0x041e, 0x3040) ||
+			 mixer->chip->usb_id == USB_ID(0x041e, 0x3042) ||
+			 mixer->chip->usb_id == USB_ID(0x041e, 0x30df) ||
+			 mixer->chip->usb_id == USB_ID(0x041e, 0x3048)))
+			break; 
+
+		knew = snd_audigy2nx_control;
+		knew.name = snd_audigy2nx_led_names[i];
+		knew.private_value = (1 << 8) | i; /* LED on as default */
+		err = add_single_ctl_with_resume(mixer, 0,
+						 snd_audigy2nx_led_resume,
+						 &knew, NULL);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static void snd_audigy2nx_proc_read(struct snd_info_entry *entry,
+				    struct snd_info_buffer *buffer)
+{
+	static const struct sb_jack {
+		int unitid;
+		const char *name;
+	}  jacks_audigy2nx[] = {
+		{4,  "dig in "},
+		{7,  "line in"},
+		{19, "spk out"},
+		{20, "hph out"},
+		{-1, NULL}
+	}, jacks_live24ext[] = {
+		{4,  "line in"}, /* &1=Line, &2=Mic*/
+		{3,  "hph out"}, /* headphones */
+		{0,  "RC     "}, /* last command, 6 bytes see rc_config above */
+		{-1, NULL}
+	};
+	const struct sb_jack *jacks;
+	struct usb_mixer_interface *mixer = entry->private_data;
+	int i, err;
+	u8 buf[3];
+
+	snd_iprintf(buffer, "%s jacks\n\n", mixer->chip->card->shortname);
+	if (mixer->chip->usb_id == USB_ID(0x041e, 0x3020))
+		jacks = jacks_audigy2nx;
+	else if (mixer->chip->usb_id == USB_ID(0x041e, 0x3040) ||
+		 mixer->chip->usb_id == USB_ID(0x041e, 0x3048))
+		jacks = jacks_live24ext;
+	else
+		return;
+
+	for (i = 0; jacks[i].name; ++i) {
+		snd_iprintf(buffer, "%s: ", jacks[i].name);
+		err = snd_usb_lock_shutdown(mixer->chip);
+		if (err < 0)
+			return;
+		err = snd_usb_ctl_msg(mixer->chip->dev,
+				      usb_rcvctrlpipe(mixer->chip->dev, 0),
+				      UAC_GET_MEM, USB_DIR_IN | USB_TYPE_CLASS |
+				      USB_RECIP_INTERFACE, 0,
+				      jacks[i].unitid << 8, buf, 3);
+		snd_usb_unlock_shutdown(mixer->chip);
+		if (err == 3 && (buf[0] == 3 || buf[0] == 6))
+			snd_iprintf(buffer, "%02x %02x\n", buf[1], buf[2]);
+		else
+			snd_iprintf(buffer, "?\n");
+	}
+}
+
+/* EMU0204 */
+static int snd_emu0204_ch_switch_info(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_info *uinfo)
+{
+	static const char * const texts[2] = {"1/2", "3/4"};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_emu0204_ch_switch_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kcontrol->private_value;
+	return 0;
+}
+
+static int snd_emu0204_ch_switch_update(struct usb_mixer_interface *mixer,
+					int value)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+	unsigned char buf[2];
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	buf[0] = 0x01;
+	buf[1] = value ? 0x02 : 0x01;
+	err = snd_usb_ctl_msg(chip->dev,
+		      usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
+		      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+		      0x0400, 0x0e00, buf, 2);
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_emu0204_ch_switch_put(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+	unsigned int value = ucontrol->value.enumerated.item[0];
+	int err;
+
+	if (value > 1)
+		return -EINVAL;
+
+	if (value == kcontrol->private_value)
+		return 0;
+
+	kcontrol->private_value = value;
+	err = snd_emu0204_ch_switch_update(mixer, value);
+	return err < 0 ? err : 1;
+}
+
+static int snd_emu0204_ch_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_emu0204_ch_switch_update(list->mixer,
+					    list->kctl->private_value);
+}
+
+static struct snd_kcontrol_new snd_emu0204_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Front Jack Channels",
+	.info = snd_emu0204_ch_switch_info,
+	.get = snd_emu0204_ch_switch_get,
+	.put = snd_emu0204_ch_switch_put,
+	.private_value = 0,
+};
+
+static int snd_emu0204_controls_create(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_emu0204_ch_switch_resume,
+					  &snd_emu0204_control, NULL);
+}
+
+/* ASUS Xonar U1 / U3 controls */
+
+static int snd_xonar_u1_switch_get(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = !!(kcontrol->private_value & 0x02);
+	return 0;
+}
+
+static int snd_xonar_u1_switch_update(struct usb_mixer_interface *mixer,
+				      unsigned char status)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0), 0x08,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      50, 0, &status, 1);
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_xonar_u1_switch_put(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 old_status, new_status;
+	int err;
+
+	old_status = kcontrol->private_value;
+	if (ucontrol->value.integer.value[0])
+		new_status = old_status | 0x02;
+	else
+		new_status = old_status & ~0x02;
+	if (new_status == old_status)
+		return 0;
+
+	kcontrol->private_value = new_status;
+	err = snd_xonar_u1_switch_update(list->mixer, new_status);
+	return err < 0 ? err : 1;
+}
+
+static int snd_xonar_u1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_xonar_u1_switch_update(list->mixer,
+					  list->kctl->private_value);
+}
+
+static struct snd_kcontrol_new snd_xonar_u1_output_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Digital Playback Switch",
+	.info = snd_ctl_boolean_mono_info,
+	.get = snd_xonar_u1_switch_get,
+	.put = snd_xonar_u1_switch_put,
+	.private_value = 0x05,
+};
+
+static int snd_xonar_u1_controls_create(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_xonar_u1_switch_resume,
+					  &snd_xonar_u1_output_switch, NULL);
+}
+
+/* Digidesign Mbox 1 clock source switch (internal/spdif) */
+
+static int snd_mbox1_switch_get(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kctl->private_value;
+	return 0;
+}
+
+static int snd_mbox1_switch_update(struct usb_mixer_interface *mixer, int val)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+	unsigned char buff[3];
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	/* Prepare for magic command to toggle clock source */
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_INTERFACE, 0x00, 0x500, buff, 1);
+	if (err < 0)
+		goto err;
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		goto err;
+
+	/* 2 possibilities:	Internal    -> send sample rate
+	 *			S/PDIF sync -> send zeroes
+	 * NB: Sample rate locked to 48kHz on purpose to
+	 *     prevent user from resetting the sample rate
+	 *     while S/PDIF sync is enabled and confusing
+	 *     this configuration.
+	 */
+	if (val == 0) {
+		buff[0] = 0x80;
+		buff[1] = 0xbb;
+		buff[2] = 0x00;
+	} else {
+		buff[0] = buff[1] = buff[2] = 0x00;
+	}
+
+	/* Send the magic command to toggle the clock source */
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_sndctrlpipe(chip->dev, 0), 0x1,
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		goto err;
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		goto err;
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0), 0x81,
+				USB_DIR_IN |
+				USB_TYPE_CLASS |
+				USB_RECIP_ENDPOINT, 0x100, 0x2, buff, 3);
+	if (err < 0)
+		goto err;
+
+err:
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_mbox1_switch_put(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int err;
+	bool cur_val, new_val;
+
+	cur_val = kctl->private_value;
+	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
+
+	kctl->private_value = new_val;
+	err = snd_mbox1_switch_update(mixer, new_val);
+	return err < 0 ? err : 1;
+}
+
+static int snd_mbox1_switch_info(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Internal",
+		"S/PDIF"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_mbox1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_mbox1_switch_update(list->mixer, list->kctl->private_value);
+}
+
+static struct snd_kcontrol_new snd_mbox1_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Clock Source",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_mbox1_switch_info,
+	.get = snd_mbox1_switch_get,
+	.put = snd_mbox1_switch_put,
+	.private_value = 0
+};
+
+static int snd_mbox1_create_sync_switch(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_mbox1_switch_resume,
+					  &snd_mbox1_switch, NULL);
+}
+
+/* Native Instruments device quirks */
+
+#define _MAKE_NI_CONTROL(bRequest,wIndex) ((bRequest) << 16 | (wIndex))
+
+static int snd_ni_control_init_val(struct usb_mixer_interface *mixer,
+				   struct snd_kcontrol *kctl)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	unsigned int pval = kctl->private_value;
+	u8 value;
+	int err;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      (pval >> 16) & 0xff,
+			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			      0, pval & 0xffff, &value, 1);
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"unable to issue vendor read request (ret = %d)", err);
+		return err;
+	}
+
+	kctl->private_value |= ((unsigned int)value << 24);
+	return 0;
+}
+
+static int snd_nativeinstruments_control_get(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value >> 24;
+	return 0;
+}
+
+static int snd_ni_update_cur_val(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	int err;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+	err = usb_control_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+			      (pval >> 16) & 0xff,
+			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+			      pval >> 24, pval & 0xffff, NULL, 0, 1000);
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_nativeinstruments_control_put(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 oldval = (kcontrol->private_value >> 24) & 0xff;
+	u8 newval = ucontrol->value.integer.value[0];
+	int err;
+
+	if (oldval == newval)
+		return 0;
+
+	kcontrol->private_value &= ~(0xff << 24);
+	kcontrol->private_value |= (unsigned int)newval << 24;
+	err = snd_ni_update_cur_val(list);
+	return err < 0 ? err : 1;
+}
+
+static struct snd_kcontrol_new snd_nativeinstruments_ta6_mixers[] = {
+	{
+		.name = "Direct Thru Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x03),
+	},
+	{
+		.name = "Direct Thru Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x05),
+	},
+	{
+		.name = "Phono Input Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x03),
+	},
+	{
+		.name = "Phono Input Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x05),
+	},
+};
+
+static struct snd_kcontrol_new snd_nativeinstruments_ta10_mixers[] = {
+	{
+		.name = "Direct Thru Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x03),
+	},
+	{
+		.name = "Direct Thru Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x05),
+	},
+	{
+		.name = "Direct Thru Channel C",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x07),
+	},
+	{
+		.name = "Direct Thru Channel D",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x09),
+	},
+	{
+		.name = "Phono Input Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x03),
+	},
+	{
+		.name = "Phono Input Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x05),
+	},
+	{
+		.name = "Phono Input Channel C",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x07),
+	},
+	{
+		.name = "Phono Input Channel D",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x09),
+	},
+};
+
+static int snd_nativeinstruments_create_mixer(struct usb_mixer_interface *mixer,
+					      const struct snd_kcontrol_new *kc,
+					      unsigned int count)
+{
+	int i, err = 0;
+	struct snd_kcontrol_new template = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.get = snd_nativeinstruments_control_get,
+		.put = snd_nativeinstruments_control_put,
+		.info = snd_ctl_boolean_mono_info,
+	};
+
+	for (i = 0; i < count; i++) {
+		struct usb_mixer_elem_list *list;
+
+		template.name = kc[i].name;
+		template.private_value = kc[i].private_value;
+
+		err = add_single_ctl_with_resume(mixer, 0,
+						 snd_ni_update_cur_val,
+						 &template, &list);
+		if (err < 0)
+			break;
+		snd_ni_control_init_val(mixer, list->kctl);
+	}
+
+	return err;
+}
+
+/* M-Audio FastTrack Ultra quirks */
+/* FTU Effect switch (also used by C400/C600) */
+static int snd_ftu_eff_switch_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[8] = {
+		"Room 1", "Room 2", "Room 3", "Hall 1",
+		"Hall 2", "Plate", "Delay", "Echo"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_ftu_eff_switch_init(struct usb_mixer_interface *mixer,
+				   struct snd_kcontrol *kctl)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	unsigned int pval = kctl->private_value;
+	int err;
+	unsigned char value[2];
+
+	value[0] = 0x00;
+	value[1] = 0x00;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			      pval & 0xff00,
+			      snd_usb_ctrl_intf(mixer->chip) | ((pval & 0xff) << 8),
+			      value, 2);
+	if (err < 0)
+		return err;
+
+	kctl->private_value |= (unsigned int)value[0] << 24;
+	return 0;
+}
+
+static int snd_ftu_eff_switch_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kctl->private_value >> 24;
+	return 0;
+}
+
+static int snd_ftu_eff_switch_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	unsigned char value[2];
+	int err;
+
+	value[0] = pval >> 24;
+	value[1] = 0;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0),
+			      UAC_SET_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			      pval & 0xff00,
+			      snd_usb_ctrl_intf(chip) | ((pval & 0xff) << 8),
+			      value, 2);
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_ftu_eff_switch_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	unsigned int pval = list->kctl->private_value;
+	int cur_val, err, new_val;
+
+	cur_val = pval >> 24;
+	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
+
+	kctl->private_value &= ~(0xff << 24);
+	kctl->private_value |= new_val << 24;
+	err = snd_ftu_eff_switch_update(list);
+	return err < 0 ? err : 1;
+}
+
+static int snd_ftu_create_effect_switch(struct usb_mixer_interface *mixer,
+	int validx, int bUnitID)
+{
+	static struct snd_kcontrol_new template = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Effect Program Switch",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_ftu_eff_switch_info,
+		.get = snd_ftu_eff_switch_get,
+		.put = snd_ftu_eff_switch_put
+	};
+	struct usb_mixer_elem_list *list;
+	int err;
+
+	err = add_single_ctl_with_resume(mixer, bUnitID,
+					 snd_ftu_eff_switch_update,
+					 &template, &list);
+	if (err < 0)
+		return err;
+	list->kctl->private_value = (validx << 8) | bUnitID;
+	snd_ftu_eff_switch_init(mixer, list->kctl);
+	return 0;
+}
+
+/* Create volume controls for FTU devices*/
+static int snd_ftu_create_volume_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int control, cmask;
+	int in, out, err;
+
+	const unsigned int id = 5;
+	const int val_type = USB_MIXER_S16;
+
+	for (out = 0; out < 8; out++) {
+		control = out + 1;
+		for (in = 0; in < 8; in++) {
+			cmask = 1 << in;
+			snprintf(name, sizeof(name),
+				"AIn%d - Out%d Capture Volume",
+				in  + 1, out + 1);
+			err = snd_create_std_mono_ctl(mixer, id, control,
+							cmask, val_type, name,
+							&snd_usb_mixer_vol_tlv);
+			if (err < 0)
+				return err;
+		}
+		for (in = 8; in < 16; in++) {
+			cmask = 1 << in;
+			snprintf(name, sizeof(name),
+				"DIn%d - Out%d Playback Volume",
+				in - 7, out + 1);
+			err = snd_create_std_mono_ctl(mixer, id, control,
+							cmask, val_type, name,
+							&snd_usb_mixer_vol_tlv);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_ftu_create_effect_volume_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Volume";
+	const unsigned int id = 6;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 2;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_ftu_create_effect_duration_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Duration";
+	const unsigned int id = 6;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 3;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_ftu_create_effect_feedback_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Feedback Volume";
+	const unsigned int id = 6;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 4;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, NULL);
+}
+
+static int snd_ftu_create_effect_return_ctls(struct usb_mixer_interface *mixer)
+{
+	unsigned int cmask;
+	int err, ch;
+	char name[48];
+
+	const unsigned int id = 7;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 7;
+
+	for (ch = 0; ch < 4; ++ch) {
+		cmask = 1 << ch;
+		snprintf(name, sizeof(name),
+			"Effect Return %d Volume", ch + 1);
+		err = snd_create_std_mono_ctl(mixer, id, control,
+						cmask, val_type, name,
+						snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int snd_ftu_create_effect_send_ctls(struct usb_mixer_interface *mixer)
+{
+	unsigned int  cmask;
+	int err, ch;
+	char name[48];
+
+	const unsigned int id = 5;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 9;
+
+	for (ch = 0; ch < 8; ++ch) {
+		cmask = 1 << ch;
+		snprintf(name, sizeof(name),
+			"Effect Send AIn%d Volume", ch + 1);
+		err = snd_create_std_mono_ctl(mixer, id, control, cmask,
+						val_type, name,
+						snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+	for (ch = 8; ch < 16; ++ch) {
+		cmask = 1 << ch;
+		snprintf(name, sizeof(name),
+			"Effect Send DIn%d Volume", ch - 7);
+		err = snd_create_std_mono_ctl(mixer, id, control, cmask,
+						val_type, name,
+						snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static int snd_ftu_create_mixer(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = snd_ftu_create_volume_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_switch(mixer, 1, 6);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_volume_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_duration_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_feedback_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_return_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_send_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
+			       unsigned char samplerate_id)
+{
+	struct usb_mixer_interface *mixer;
+	struct usb_mixer_elem_info *cval;
+	int unitid = 12; /* SampleRate ExtensionUnit ID */
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		if (mixer->id_elems[unitid]) {
+			cval = mixer_elem_list_to_info(mixer->id_elems[unitid]);
+			snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR,
+						    cval->control << 8,
+						    samplerate_id);
+			snd_usb_mixer_notify_id(mixer, unitid);
+			break;
+		}
+	}
+}
+
+/* M-Audio Fast Track C400/C600 */
+/* C400/C600 volume controls, this control needs a volume quirk, see mixer.c */
+static int snd_c400_create_vol_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int cmask, offset;
+	int out, chan, err;
+	int num_outs = 0;
+	int num_ins = 0;
+
+	const unsigned int id = 0x40;
+	const int val_type = USB_MIXER_S16;
+	const int control = 1;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0763, 0x2030):
+		num_outs = 6;
+		num_ins = 4;
+		break;
+	case USB_ID(0x0763, 0x2031):
+		num_outs = 8;
+		num_ins = 6;
+		break;
+	}
+
+	for (chan = 0; chan < num_outs + num_ins; chan++) {
+		for (out = 0; out < num_outs; out++) {
+			if (chan < num_outs) {
+				snprintf(name, sizeof(name),
+					"PCM%d-Out%d Playback Volume",
+					chan + 1, out + 1);
+			} else {
+				snprintf(name, sizeof(name),
+					"In%d-Out%d Playback Volume",
+					chan - num_outs + 1, out + 1);
+			}
+
+			cmask = (out == 0) ? 0 : 1 << (out - 1);
+			offset = chan * num_outs;
+			err = snd_create_std_mono_ctl_offset(mixer, id, control,
+						cmask, val_type, offset, name,
+						&snd_usb_mixer_vol_tlv);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_c400_create_effect_volume_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Volume";
+	const unsigned int id = 0x43;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 3;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_c400_create_effect_duration_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Duration";
+	const unsigned int id = 0x43;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 4;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_c400_create_effect_feedback_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Feedback Volume";
+	const unsigned int id = 0x43;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 5;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, NULL);
+}
+
+static int snd_c400_create_effect_vol_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int cmask;
+	int chan, err;
+	int num_outs = 0;
+	int num_ins = 0;
+
+	const unsigned int id = 0x42;
+	const int val_type = USB_MIXER_S16;
+	const int control = 1;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0763, 0x2030):
+		num_outs = 6;
+		num_ins = 4;
+		break;
+	case USB_ID(0x0763, 0x2031):
+		num_outs = 8;
+		num_ins = 6;
+		break;
+	}
+
+	for (chan = 0; chan < num_outs + num_ins; chan++) {
+		if (chan < num_outs) {
+			snprintf(name, sizeof(name),
+				"Effect Send DOut%d",
+				chan + 1);
+		} else {
+			snprintf(name, sizeof(name),
+				"Effect Send AIn%d",
+				chan - num_outs + 1);
+		}
+
+		cmask = (chan == 0) ? 0 : 1 << (chan - 1);
+		err = snd_create_std_mono_ctl(mixer, id, control,
+						cmask, val_type, name,
+						&snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int snd_c400_create_effect_ret_vol_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int cmask;
+	int chan, err;
+	int num_outs = 0;
+	int offset = 0;
+
+	const unsigned int id = 0x40;
+	const int val_type = USB_MIXER_S16;
+	const int control = 1;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0763, 0x2030):
+		num_outs = 6;
+		offset = 0x3c;
+		/* { 0x3c, 0x43, 0x3e, 0x45, 0x40, 0x47 } */
+		break;
+	case USB_ID(0x0763, 0x2031):
+		num_outs = 8;
+		offset = 0x70;
+		/* { 0x70, 0x79, 0x72, 0x7b, 0x74, 0x7d, 0x76, 0x7f } */
+		break;
+	}
+
+	for (chan = 0; chan < num_outs; chan++) {
+		snprintf(name, sizeof(name),
+			"Effect Return %d",
+			chan + 1);
+
+		cmask = (chan == 0) ? 0 :
+			1 << (chan + (chan % 2) * num_outs - 1);
+		err = snd_create_std_mono_ctl_offset(mixer, id, control,
+						cmask, val_type, offset, name,
+						&snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int snd_c400_create_mixer(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = snd_c400_create_vol_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_vol_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_ret_vol_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_switch(mixer, 2, 0x43);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_volume_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_duration_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_feedback_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * The mixer units for Ebox-44 are corrupt, and even where they
+ * are valid they presents mono controls as L and R channels of
+ * stereo. So we provide a good mixer here.
+ */
+static const struct std_mono_table ebox44_table[] = {
+	{
+		.unitid = 4,
+		.control = 1,
+		.cmask = 0x0,
+		.val_type = USB_MIXER_INV_BOOLEAN,
+		.name = "Headphone Playback Switch"
+	},
+	{
+		.unitid = 4,
+		.control = 2,
+		.cmask = 0x1,
+		.val_type = USB_MIXER_S16,
+		.name = "Headphone A Mix Playback Volume"
+	},
+	{
+		.unitid = 4,
+		.control = 2,
+		.cmask = 0x2,
+		.val_type = USB_MIXER_S16,
+		.name = "Headphone B Mix Playback Volume"
+	},
+
+	{
+		.unitid = 7,
+		.control = 1,
+		.cmask = 0x0,
+		.val_type = USB_MIXER_INV_BOOLEAN,
+		.name = "Output Playback Switch"
+	},
+	{
+		.unitid = 7,
+		.control = 2,
+		.cmask = 0x1,
+		.val_type = USB_MIXER_S16,
+		.name = "Output A Playback Volume"
+	},
+	{
+		.unitid = 7,
+		.control = 2,
+		.cmask = 0x2,
+		.val_type = USB_MIXER_S16,
+		.name = "Output B Playback Volume"
+	},
+
+	{
+		.unitid = 10,
+		.control = 1,
+		.cmask = 0x0,
+		.val_type = USB_MIXER_INV_BOOLEAN,
+		.name = "Input Capture Switch"
+	},
+	{
+		.unitid = 10,
+		.control = 2,
+		.cmask = 0x1,
+		.val_type = USB_MIXER_S16,
+		.name = "Input A Capture Volume"
+	},
+	{
+		.unitid = 10,
+		.control = 2,
+		.cmask = 0x2,
+		.val_type = USB_MIXER_S16,
+		.name = "Input B Capture Volume"
+	},
+
+	{}
+};
+
+/* Audio Advantage Micro II findings:
+ *
+ * Mapping spdif AES bits to vendor register.bit:
+ * AES0: [0 0 0 0 2.3 2.2 2.1 2.0] - default 0x00
+ * AES1: [3.3 3.2.3.1.3.0 2.7 2.6 2.5 2.4] - default: 0x01
+ * AES2: [0 0 0 0 0 0 0 0]
+ * AES3: [0 0 0 0 0 0 x 0] - 'x' bit is set basing on standard usb request
+ *                           (UAC_EP_CS_ATTR_SAMPLE_RATE) for Audio Devices
+ *
+ * power on values:
+ * r2: 0x10
+ * r3: 0x20 (b7 is zeroed just before playback (except IEC61937) and set
+ *           just after it to 0xa0, presumably it disables/mutes some analog
+ *           parts when there is no audio.)
+ * r9: 0x28
+ *
+ * Optical transmitter on/off:
+ * vendor register.bit: 9.1
+ * 0 - on (0x28 register value)
+ * 1 - off (0x2a register value)
+ *
+ */
+static int snd_microii_spdif_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
+	uinfo->count = 1;
+	return 0;
+}
+
+static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	int err;
+	struct usb_interface *iface;
+	struct usb_host_interface *alts;
+	unsigned int ep;
+	unsigned char data[3];
+	int rate;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.iec958.status[0] = kcontrol->private_value & 0xff;
+	ucontrol->value.iec958.status[1] = (kcontrol->private_value >> 8) & 0xff;
+	ucontrol->value.iec958.status[2] = 0x00;
+
+	/* use known values for that card: interface#1 altsetting#1 */
+	iface = usb_ifnum_to_if(chip->dev, 1);
+	if (!iface || iface->num_altsetting < 2) {
+		err = -EINVAL;
+		goto end;
+	}
+	alts = &iface->altsetting[1];
+	if (get_iface_desc(alts)->bNumEndpoints < 1) {
+		err = -EINVAL;
+		goto end;
+	}
+	ep = get_endpoint(alts, 0)->bEndpointAddress;
+
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_rcvctrlpipe(chip->dev, 0),
+			UAC_GET_CUR,
+			USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
+			UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
+			ep,
+			data,
+			sizeof(data));
+	if (err < 0)
+		goto end;
+
+	rate = data[0] | (data[1] << 8) | (data[2] << 16);
+	ucontrol->value.iec958.status[3] = (rate == 48000) ?
+			IEC958_AES3_CON_FS_48000 : IEC958_AES3_CON_FS_44100;
+
+	err = 0;
+ end:
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_microii_spdif_default_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	u8 reg;
+	int err;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	reg = ((pval >> 4) & 0xf0) | (pval & 0x0f);
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0),
+			UAC_SET_CUR,
+			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			reg,
+			2,
+			NULL,
+			0);
+	if (err < 0)
+		goto end;
+
+	reg = (pval & IEC958_AES0_NONAUDIO) ? 0xa0 : 0x20;
+	reg |= (pval >> 12) & 0x0f;
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0),
+			UAC_SET_CUR,
+			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			reg,
+			3,
+			NULL,
+			0);
+	if (err < 0)
+		goto end;
+
+ end:
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_microii_spdif_default_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	unsigned int pval, pval_old;
+	int err;
+
+	pval = pval_old = kcontrol->private_value;
+	pval &= 0xfffff0f0;
+	pval |= (ucontrol->value.iec958.status[1] & 0x0f) << 8;
+	pval |= (ucontrol->value.iec958.status[0] & 0x0f);
+
+	pval &= 0xffff0fff;
+	pval |= (ucontrol->value.iec958.status[1] & 0xf0) << 8;
+
+	/* The frequency bits in AES3 cannot be set via register access. */
+
+	/* Silently ignore any bits from the request that cannot be set. */
+
+	if (pval == pval_old)
+		return 0;
+
+	kcontrol->private_value = pval;
+	err = snd_microii_spdif_default_update(list);
+	return err < 0 ? err : 1;
+}
+
+static int snd_microii_spdif_mask_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.iec958.status[0] = 0x0f;
+	ucontrol->value.iec958.status[1] = 0xff;
+	ucontrol->value.iec958.status[2] = 0x00;
+	ucontrol->value.iec958.status[3] = 0x00;
+
+	return 0;
+}
+
+static int snd_microii_spdif_switch_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = !(kcontrol->private_value & 0x02);
+
+	return 0;
+}
+
+static int snd_microii_spdif_switch_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	u8 reg = list->kctl->private_value;
+	int err;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0),
+			UAC_SET_CUR,
+			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			reg,
+			9,
+			NULL,
+			0);
+
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_microii_spdif_switch_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 reg;
+	int err;
+
+	reg = ucontrol->value.integer.value[0] ? 0x28 : 0x2a;
+	if (reg != list->kctl->private_value)
+		return 0;
+
+	kcontrol->private_value = reg;
+	err = snd_microii_spdif_switch_update(list);
+	return err < 0 ? err : 1;
+}
+
+static struct snd_kcontrol_new snd_microii_mixer_spdif[] = {
+	{
+		.iface =    SNDRV_CTL_ELEM_IFACE_PCM,
+		.name =     SNDRV_CTL_NAME_IEC958("", PLAYBACK, DEFAULT),
+		.info =     snd_microii_spdif_info,
+		.get =      snd_microii_spdif_default_get,
+		.put =      snd_microii_spdif_default_put,
+		.private_value = 0x00000100UL,/* reset value */
+	},
+	{
+		.access =   SNDRV_CTL_ELEM_ACCESS_READ,
+		.iface =    SNDRV_CTL_ELEM_IFACE_PCM,
+		.name =     SNDRV_CTL_NAME_IEC958("", PLAYBACK, MASK),
+		.info =     snd_microii_spdif_info,
+		.get =      snd_microii_spdif_mask_get,
+	},
+	{
+		.iface =    SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name =     SNDRV_CTL_NAME_IEC958("", PLAYBACK, SWITCH),
+		.info =     snd_ctl_boolean_mono_info,
+		.get =      snd_microii_spdif_switch_get,
+		.put =      snd_microii_spdif_switch_put,
+		.private_value = 0x00000028UL,/* reset value */
+	}
+};
+
+static int snd_microii_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i;
+	static const usb_mixer_elem_resume_func_t resume_funcs[] = {
+		snd_microii_spdif_default_update,
+		NULL,
+		snd_microii_spdif_switch_update
+	};
+
+	for (i = 0; i < ARRAY_SIZE(snd_microii_mixer_spdif); ++i) {
+		err = add_single_ctl_with_resume(mixer, 0,
+						 resume_funcs[i],
+						 &snd_microii_mixer_spdif[i],
+						 NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/* Creative Sound Blaster E1 */
+
+static int snd_soundblaster_e1_switch_get(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value;
+	return 0;
+}
+
+static int snd_soundblaster_e1_switch_update(struct usb_mixer_interface *mixer,
+					     unsigned char state)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+	unsigned char buff[2];
+
+	buff[0] = 0x02;
+	buff[1] = state ? 0x02 : 0x00;
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return err;
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_sndctrlpipe(chip->dev, 0), HID_REQ_SET_REPORT,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
+			0x0202, 3, buff, 2);
+	snd_usb_unlock_shutdown(chip);
+	return err;
+}
+
+static int snd_soundblaster_e1_switch_put(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	unsigned char value = !!ucontrol->value.integer.value[0];
+	int err;
+
+	if (kcontrol->private_value == value)
+		return 0;
+	kcontrol->private_value = value;
+	err = snd_soundblaster_e1_switch_update(list->mixer, value);
+	return err < 0 ? err : 1;
+}
+
+static int snd_soundblaster_e1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_soundblaster_e1_switch_update(list->mixer,
+						 list->kctl->private_value);
+}
+
+static int snd_soundblaster_e1_switch_info(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Mic", "Aux"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static struct snd_kcontrol_new snd_soundblaster_e1_input_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Input Source",
+	.info = snd_soundblaster_e1_switch_info,
+	.get = snd_soundblaster_e1_switch_get,
+	.put = snd_soundblaster_e1_switch_put,
+	.private_value = 0,
+};
+
+static int snd_soundblaster_e1_switch_create(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_soundblaster_e1_switch_resume,
+					  &snd_soundblaster_e1_input_switch,
+					  NULL);
+}
+
+static void dell_dock_init_vol(struct snd_usb_audio *chip, int ch, int id)
+{
+	u16 buf = 0;
+
+	snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			ch, snd_usb_ctrl_intf(chip) | (id << 8),
+			&buf, 2);
+}
+
+static int dell_dock_mixer_init(struct usb_mixer_interface *mixer)
+{
+	/* fix to 0dB playback volumes */
+	dell_dock_init_vol(mixer->chip, 1, 16);
+	dell_dock_init_vol(mixer->chip, 2, 16);
+	dell_dock_init_vol(mixer->chip, 1, 19);
+	dell_dock_init_vol(mixer->chip, 2, 19);
+	return 0;
+}
+
+int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
+{
+	int err = 0;
+	struct snd_info_entry *entry;
+
+	err = snd_usb_soundblaster_remote_init(mixer);
+	if (err < 0)
+		return err;
+
+	switch (mixer->chip->usb_id) {
+	/* Tascam US-16x08 */
+	case USB_ID(0x0644, 0x8047):
+		err = snd_us16x08_controls_create(mixer);
+		break;
+	case USB_ID(0x041e, 0x3020):
+	case USB_ID(0x041e, 0x3040):
+	case USB_ID(0x041e, 0x3042):
+	case USB_ID(0x041e, 0x30df):
+	case USB_ID(0x041e, 0x3048):
+		err = snd_audigy2nx_controls_create(mixer);
+		if (err < 0)
+			break;
+		if (!snd_card_proc_new(mixer->chip->card, "audigy2nx", &entry))
+			snd_info_set_text_ops(entry, mixer,
+					      snd_audigy2nx_proc_read);
+		break;
+
+	/* EMU0204 */
+	case USB_ID(0x041e, 0x3f19):
+		err = snd_emu0204_controls_create(mixer);
+		break;
+
+	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
+	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C400 */
+		err = snd_c400_create_mixer(mixer);
+		break;
+
+	case USB_ID(0x0763, 0x2080): /* M-Audio Fast Track Ultra */
+	case USB_ID(0x0763, 0x2081): /* M-Audio Fast Track Ultra 8R */
+		err = snd_ftu_create_mixer(mixer);
+		break;
+
+	case USB_ID(0x0b05, 0x1739): /* ASUS Xonar U1 */
+	case USB_ID(0x0b05, 0x1743): /* ASUS Xonar U1 (2) */
+	case USB_ID(0x0b05, 0x17a0): /* ASUS Xonar U3 */
+		err = snd_xonar_u1_controls_create(mixer);
+		break;
+
+	case USB_ID(0x0d8c, 0x0103): /* Audio Advantage Micro II */
+		err = snd_microii_controls_create(mixer);
+		break;
+
+	case USB_ID(0x0dba, 0x1000): /* Digidesign Mbox 1 */
+		err = snd_mbox1_create_sync_switch(mixer);
+		break;
+
+	case USB_ID(0x17cc, 0x1011): /* Traktor Audio 6 */
+		err = snd_nativeinstruments_create_mixer(mixer,
+				snd_nativeinstruments_ta6_mixers,
+				ARRAY_SIZE(snd_nativeinstruments_ta6_mixers));
+		break;
+
+	case USB_ID(0x17cc, 0x1021): /* Traktor Audio 10 */
+		err = snd_nativeinstruments_create_mixer(mixer,
+				snd_nativeinstruments_ta10_mixers,
+				ARRAY_SIZE(snd_nativeinstruments_ta10_mixers));
+		break;
+
+	case USB_ID(0x200c, 0x1018): /* Electrix Ebox-44 */
+		/* detection is disabled in mixer_maps.c */
+		err = snd_create_std_mono_table(mixer, ebox44_table);
+		break;
+
+	case USB_ID(0x1235, 0x8012): /* Focusrite Scarlett 6i6 */
+	case USB_ID(0x1235, 0x8002): /* Focusrite Scarlett 8i6 */
+	case USB_ID(0x1235, 0x8004): /* Focusrite Scarlett 18i6 */
+	case USB_ID(0x1235, 0x8014): /* Focusrite Scarlett 18i8 */
+	case USB_ID(0x1235, 0x800c): /* Focusrite Scarlett 18i20 */
+		err = snd_scarlett_controls_create(mixer);
+		break;
+
+	case USB_ID(0x041e, 0x323b): /* Creative Sound Blaster E1 */
+		err = snd_soundblaster_e1_switch_create(mixer);
+		break;
+	case USB_ID(0x0bda, 0x4014): /* Dell WD15 dock */
+		err = dell_dock_mixer_init(mixer);
+		break;
+	}
+
+	return err;
+}
+
+#ifdef CONFIG_PM
+void snd_usb_mixer_resume_quirk(struct usb_mixer_interface *mixer)
+{
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0bda, 0x4014): /* Dell WD15 dock */
+		dell_dock_mixer_init(mixer);
+		break;
+	}
+}
+#endif
+
+void snd_usb_mixer_rc_memory_change(struct usb_mixer_interface *mixer,
+				    int unitid)
+{
+	if (!mixer->rc_cfg)
+		return;
+	/* unit ids specific to Extigy/Audigy 2 NX: */
+	switch (unitid) {
+	case 0: /* remote control */
+		mixer->rc_urb->dev = mixer->chip->dev;
+		usb_submit_urb(mixer->rc_urb, GFP_ATOMIC);
+		break;
+	case 4: /* digital in jack */
+	case 7: /* line in jacks */
+	case 19: /* speaker out jacks */
+	case 20: /* headphones out jack */
+		break;
+	/* live24ext: 4 = line-in jack */
+	case 3:	/* hp-out jack (may actuate Mute) */
+		if (mixer->chip->usb_id == USB_ID(0x041e, 0x3040) ||
+		    mixer->chip->usb_id == USB_ID(0x041e, 0x3048))
+			snd_usb_mixer_notify_id(mixer, mixer->rc_cfg->mute_mixer_id);
+		break;
+	default:
+		usb_audio_dbg(mixer->chip, "memory change in unknown unit %d\n", unitid);
+		break;
+	}
+}
+
+static void snd_dragonfly_quirk_db_scale(struct usb_mixer_interface *mixer,
+					 struct usb_mixer_elem_info *cval,
+					 struct snd_kcontrol *kctl)
+{
+	/* Approximation using 10 ranges based on output measurement on hw v1.2.
+	 * This seems close to the cubic mapping e.g. alsamixer uses. */
+	static const DECLARE_TLV_DB_RANGE(scale,
+		 0,  1, TLV_DB_MINMAX_ITEM(-5300, -4970),
+		 2,  5, TLV_DB_MINMAX_ITEM(-4710, -4160),
+		 6,  7, TLV_DB_MINMAX_ITEM(-3884, -3710),
+		 8, 14, TLV_DB_MINMAX_ITEM(-3443, -2560),
+		15, 16, TLV_DB_MINMAX_ITEM(-2475, -2324),
+		17, 19, TLV_DB_MINMAX_ITEM(-2228, -2031),
+		20, 26, TLV_DB_MINMAX_ITEM(-1910, -1393),
+		27, 31, TLV_DB_MINMAX_ITEM(-1322, -1032),
+		32, 40, TLV_DB_MINMAX_ITEM(-968, -490),
+		41, 50, TLV_DB_MINMAX_ITEM(-441, 0),
+	);
+
+	if (cval->min == 0 && cval->max == 50) {
+		usb_audio_info(mixer->chip, "applying DragonFly dB scale quirk (0-50 variant)\n");
+		kctl->tlv.p = scale;
+		kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
+		kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+
+	} else if (cval->min == 0 && cval->max <= 1000) {
+		/* Some other clearly broken DragonFly variant.
+		 * At least a 0..53 variant (hw v1.0) exists.
+		 */
+		usb_audio_info(mixer->chip, "ignoring too narrow dB range on a DragonFly device");
+		kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+	}
+}
+
+void snd_usb_mixer_fu_apply_quirk(struct usb_mixer_interface *mixer,
+				  struct usb_mixer_elem_info *cval, int unitid,
+				  struct snd_kcontrol *kctl)
+{
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x21b4, 0x0081): /* AudioQuest DragonFly */
+		if (unitid == 7 && cval->control == UAC_FU_VOLUME)
+			snd_dragonfly_quirk_db_scale(mixer, cval, kctl);
+		break;
+	/* lowest playback value is muted on some devices */
+	case USB_ID(0x0d8c, 0x000c): /* C-Media */
+	case USB_ID(0x0d8c, 0x0014): /* C-Media */
+	case USB_ID(0x19f7, 0x0003): /* RODE NT-USB */
+		if (strstr(kctl->id.name, "Playback"))
+			cval->min_mute = 1;
+		break;
+	}
+}
+