Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1545 insertions, 0 deletions

diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
new file mode 100644
index 000000000000..5f1906915aa6
--- /dev/null
+++ b/sound/usb/usbmixer.c
@@ -0,0 +1,1545 @@
+/*
+ *   (Tentative) USB Audio Driver for ALSA
+ *
+ *   Mixer control part
+ *
+ *   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)
+ *
+ *
+ *   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 <sound/driver.h>
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+#include <sound/core.h>
+#include <sound/control.h>
+
+#include "usbaudio.h"
+
+
+/*
+ */
+
+/* ignore error from controls - for debugging */
+/* #define IGNORE_CTL_ERROR */
+
+typedef struct usb_mixer_build mixer_build_t;
+typedef struct usb_audio_term usb_audio_term_t;
+typedef struct usb_mixer_elem_info usb_mixer_elem_info_t;
+
+
+struct usb_audio_term {
+	int id;
+	int type;
+	int channels;
+	unsigned int chconfig;
+	int name;
+};
+
+struct usbmix_name_map;
+
+struct usb_mixer_build {
+	snd_usb_audio_t *chip;
+	unsigned char *buffer;
+	unsigned int buflen;
+	unsigned int ctrlif;
+	unsigned short vendor;
+	unsigned short product;
+	DECLARE_BITMAP(unitbitmap, 32*32);
+	usb_audio_term_t oterm;
+	const struct usbmix_name_map *map;
+};
+
+struct usb_mixer_elem_info {
+	snd_usb_audio_t *chip;
+	unsigned int ctrlif;
+	unsigned int id;
+	unsigned int control;	/* CS or ICN (high byte) */
+	unsigned int cmask; /* channel mask bitmap: 0 = master */
+	int channels;
+	int val_type;
+	int min, max, res;
+	unsigned int initialized: 1;
+};
+
+
+enum {
+	USB_FEATURE_NONE = 0,
+	USB_FEATURE_MUTE = 1,
+	USB_FEATURE_VOLUME,
+	USB_FEATURE_BASS,
+	USB_FEATURE_MID,
+	USB_FEATURE_TREBLE,
+	USB_FEATURE_GEQ,
+	USB_FEATURE_AGC,
+	USB_FEATURE_DELAY,
+	USB_FEATURE_BASSBOOST,
+	USB_FEATURE_LOUDNESS
+};
+
+enum {
+	USB_MIXER_BOOLEAN,
+	USB_MIXER_INV_BOOLEAN,
+	USB_MIXER_S8,
+	USB_MIXER_U8,
+	USB_MIXER_S16,
+	USB_MIXER_U16,
+};
+
+enum {
+	USB_PROC_UPDOWN = 1,
+	USB_PROC_UPDOWN_SWITCH = 1,
+	USB_PROC_UPDOWN_MODE_SEL = 2,
+
+	USB_PROC_PROLOGIC = 2,
+	USB_PROC_PROLOGIC_SWITCH = 1,
+	USB_PROC_PROLOGIC_MODE_SEL = 2,
+
+	USB_PROC_3DENH = 3,
+	USB_PROC_3DENH_SWITCH = 1,
+	USB_PROC_3DENH_SPACE = 2,
+
+	USB_PROC_REVERB = 4,
+	USB_PROC_REVERB_SWITCH = 1,
+	USB_PROC_REVERB_LEVEL = 2,
+	USB_PROC_REVERB_TIME = 3,
+	USB_PROC_REVERB_DELAY = 4,
+
+	USB_PROC_CHORUS = 5,
+	USB_PROC_CHORUS_SWITCH = 1,
+	USB_PROC_CHORUS_LEVEL = 2,
+	USB_PROC_CHORUS_RATE = 3,
+	USB_PROC_CHORUS_DEPTH = 4,
+
+	USB_PROC_DCR = 6,
+	USB_PROC_DCR_SWITCH = 1,
+	USB_PROC_DCR_RATIO = 2,
+	USB_PROC_DCR_MAX_AMP = 3,
+	USB_PROC_DCR_THRESHOLD = 4,
+	USB_PROC_DCR_ATTACK = 5,
+	USB_PROC_DCR_RELEASE = 6,
+};
+
+#define MAX_CHANNELS	10	/* max logical channels */
+
+
+/*
+ * manual mapping of mixer names
+ * if the mixer topology is too complicated and the parsed names are
+ * ambiguous, add the entries in usbmixer_maps.c.
+ */
+#include "usbmixer_maps.c"
+
+/* get the mapped name if the unit matches */
+static int check_mapped_name(mixer_build_t *state, int unitid, int control, char *buf, int buflen)
+{
+	const struct usbmix_name_map *p;
+
+	if (! state->map)
+		return 0;
+
+	for (p = state->map; p->id; p++) {
+		if (p->id == unitid && p->name &&
+		    (! control || ! p->control || control == p->control)) {
+			buflen--;
+			return strlcpy(buf, p->name, buflen);
+		}
+	}
+	return 0;
+}
+
+/* check whether the control should be ignored */
+static int check_ignored_ctl(mixer_build_t *state, int unitid, int control)
+{
+	const struct usbmix_name_map *p;
+
+	if (! state->map)
+		return 0;
+	for (p = state->map; p->id; p++) {
+		if (p->id == unitid && ! p->name &&
+		    (! control || ! p->control || control == p->control)) {
+			// printk("ignored control %d:%d\n", unitid, control);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * find an audio control unit with the given unit id
+ */
+static void *find_audio_control_unit(mixer_build_t *state, unsigned char unit)
+{
+	unsigned char *p;
+
+	p = NULL;
+	while ((p = snd_usb_find_desc(state->buffer, state->buflen, p,
+				      USB_DT_CS_INTERFACE)) != NULL) {
+		if (p[0] >= 4 && p[2] >= INPUT_TERMINAL && p[2] <= EXTENSION_UNIT && p[3] == unit)
+			return p;
+	}
+	return NULL;
+}
+
+
+/*
+ * copy a string with the given id
+ */
+static int snd_usb_copy_string_desc(mixer_build_t *state, int index, char *buf, int maxlen)
+{
+	int len = usb_string(state->chip->dev, index, buf, maxlen - 1);
+	buf[len] = 0;
+	return len;
+}
+
+/*
+ * convert from the byte/word on usb descriptor to the zero-based integer
+ */
+static int convert_signed_value(usb_mixer_elem_info_t *cval, int val)
+{
+	switch (cval->val_type) {
+	case USB_MIXER_BOOLEAN:
+		return !!val;
+	case USB_MIXER_INV_BOOLEAN:
+		return !val;
+	case USB_MIXER_U8:
+		val &= 0xff;
+		break;
+	case USB_MIXER_S8:
+		val &= 0xff;
+		if (val >= 0x80)
+			val -= 0x100;
+		break;
+	case USB_MIXER_U16:
+		val &= 0xffff;
+		break;
+	case USB_MIXER_S16:
+		val &= 0xffff;
+		if (val >= 0x8000)
+			val -= 0x10000;
+		break;
+	}
+	return val;
+}
+
+/*
+ * convert from the zero-based int to the byte/word for usb descriptor
+ */
+static int convert_bytes_value(usb_mixer_elem_info_t *cval, int val)
+{
+	switch (cval->val_type) {
+	case USB_MIXER_BOOLEAN:
+		return !!val;
+	case USB_MIXER_INV_BOOLEAN:
+		return !val;
+	case USB_MIXER_S8:
+	case USB_MIXER_U8:
+		return val & 0xff;
+	case USB_MIXER_S16:
+	case USB_MIXER_U16:
+		return val & 0xffff;
+	}
+	return 0; /* not reached */
+}
+
+static int get_relative_value(usb_mixer_elem_info_t *cval, int val)
+{
+	if (! cval->res)
+		cval->res = 1;
+	if (val < cval->min)
+		return 0;
+	else if (val > cval->max)
+		return (cval->max - cval->min) / cval->res;
+	else
+		return (val - cval->min) / cval->res;
+}
+
+static int get_abs_value(usb_mixer_elem_info_t *cval, int val)
+{
+	if (val < 0)
+		return cval->min;
+	if (! cval->res)
+		cval->res = 1;
+	val *= cval->res;
+	val += cval->min;
+	if (val > cval->max)
+		return cval->max;
+	return val;
+}
+
+
+/*
+ * retrieve a mixer value
+ */
+
+static int get_ctl_value(usb_mixer_elem_info_t *cval, int request, int validx, int *value_ret)
+{
+	unsigned char buf[2];
+	int val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
+	int timeout = 10;
+
+	while (timeout-- > 0) {
+		if (snd_usb_ctl_msg(cval->chip->dev, usb_rcvctrlpipe(cval->chip->dev, 0),
+				    request,
+				    USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+				    validx, cval->ctrlif | (cval->id << 8),
+				    buf, val_len, 100) >= 0) {
+			*value_ret = convert_signed_value(cval, snd_usb_combine_bytes(buf, val_len));
+			return 0;
+		}
+	}
+	snd_printdd(KERN_ERR "cannot get ctl value: req = 0x%x, wValue = 0x%x, wIndex = 0x%x, type = %d\n", request, validx, cval->ctrlif | (cval->id << 8), cval->val_type);
+	return -EINVAL;
+}
+
+static int get_cur_ctl_value(usb_mixer_elem_info_t *cval, int validx, int *value)
+{
+	return get_ctl_value(cval, GET_CUR, validx, value);
+}
+
+/* channel = 0: master, 1 = first channel */
+inline static int get_cur_mix_value(usb_mixer_elem_info_t *cval, int channel, int *value)
+{
+	return get_ctl_value(cval, GET_CUR, (cval->control << 8) | channel, value);
+}
+
+/*
+ * set a mixer value
+ */
+
+static int set_ctl_value(usb_mixer_elem_info_t *cval, int request, int validx, int value_set)
+{
+	unsigned char buf[2];
+	int val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
+	int timeout = 10;
+
+	value_set = convert_bytes_value(cval, value_set);
+	buf[0] = value_set & 0xff;
+	buf[1] = (value_set >> 8) & 0xff;
+	while (timeout -- > 0)
+		if (snd_usb_ctl_msg(cval->chip->dev, usb_sndctrlpipe(cval->chip->dev, 0),
+				    request,
+				    USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+				    validx, cval->ctrlif | (cval->id << 8),
+				    buf, val_len, 100) >= 0)
+			return 0;
+	snd_printdd(KERN_ERR "cannot set ctl value: req = 0x%x, wValue = 0x%x, wIndex = 0x%x, type = %d, data = 0x%x/0x%x\n", request, validx, cval->ctrlif | (cval->id << 8), cval->val_type, buf[0], buf[1]);
+	return -EINVAL;
+}
+
+static int set_cur_ctl_value(usb_mixer_elem_info_t *cval, int validx, int value)
+{
+	return set_ctl_value(cval, SET_CUR, validx, value);
+}
+
+inline static int set_cur_mix_value(usb_mixer_elem_info_t *cval, int channel, int value)
+{
+	return set_ctl_value(cval, SET_CUR, (cval->control << 8) | channel, value);
+}
+
+
+/*
+ * parser routines begin here...
+ */
+
+static int parse_audio_unit(mixer_build_t *state, int unitid);
+
+
+/*
+ * check if the input/output channel routing is enabled on the given bitmap.
+ * used for mixer unit parser
+ */
+static int check_matrix_bitmap(unsigned char *bmap, int ich, int och, int num_outs)
+{
+	int idx = ich * num_outs + och;
+	return bmap[idx >> 3] & (0x80 >> (idx & 7));
+}
+
+
+/*
+ * add an alsa control element
+ * search and increment the index until an empty slot is found.
+ *
+ * if failed, give up and free the control instance.
+ */
+
+static int add_control_to_empty(snd_card_t *card, snd_kcontrol_t *kctl)
+{
+	int err;
+	while (snd_ctl_find_id(card, &kctl->id))
+		kctl->id.index++;
+	if ((err = snd_ctl_add(card, kctl)) < 0) {
+		snd_printd(KERN_ERR "cannot add control (err = %d)\n", err);
+		snd_ctl_free_one(kctl);
+	}
+	return err;
+}
+
+
+/*
+ * get a terminal name string
+ */
+
+static struct iterm_name_combo {
+	int type;
+	char *name;
+} iterm_names[] = {
+	{ 0x0300, "Output" },
+	{ 0x0301, "Speaker" },
+	{ 0x0302, "Headphone" },
+	{ 0x0303, "HMD Audio" },
+	{ 0x0304, "Desktop Speaker" },
+	{ 0x0305, "Room Speaker" },
+	{ 0x0306, "Com Speaker" },
+	{ 0x0307, "LFE" },
+	{ 0x0600, "External In" },
+	{ 0x0601, "Analog In" },
+	{ 0x0602, "Digital In" },
+	{ 0x0603, "Line" },
+	{ 0x0604, "Legacy In" },
+	{ 0x0605, "IEC958 In" },
+	{ 0x0606, "1394 DA Stream" },
+	{ 0x0607, "1394 DV Stream" },
+	{ 0x0700, "Embedded" },
+	{ 0x0701, "Noise Source" },
+	{ 0x0702, "Equalization Noise" },
+	{ 0x0703, "CD" },
+	{ 0x0704, "DAT" },
+	{ 0x0705, "DCC" },
+	{ 0x0706, "MiniDisk" },
+	{ 0x0707, "Analog Tape" },
+	{ 0x0708, "Phonograph" },
+	{ 0x0709, "VCR Audio" },
+	{ 0x070a, "Video Disk Audio" },
+	{ 0x070b, "DVD Audio" },
+	{ 0x070c, "TV Tuner Audio" },
+	{ 0x070d, "Satellite Rec Audio" },
+	{ 0x070e, "Cable Tuner Audio" },
+	{ 0x070f, "DSS Audio" },
+	{ 0x0710, "Radio Receiver" },
+	{ 0x0711, "Radio Transmitter" },
+	{ 0x0712, "Multi-Track Recorder" },
+	{ 0x0713, "Synthesizer" },
+	{ 0 },
+};
+
+static int get_term_name(mixer_build_t *state, usb_audio_term_t *iterm,
+			 unsigned char *name, int maxlen, int term_only)
+{
+	struct iterm_name_combo *names;
+
+	if (iterm->name)
+		return snd_usb_copy_string_desc(state, iterm->name, name, maxlen);
+
+	/* virtual type - not a real terminal */
+	if (iterm->type >> 16) {
+		if (term_only)
+			return 0;
+		switch (iterm->type >> 16) {
+		case SELECTOR_UNIT:
+			strcpy(name, "Selector"); return 8;
+		case PROCESSING_UNIT:
+			strcpy(name, "Process Unit"); return 12;
+		case EXTENSION_UNIT:
+			strcpy(name, "Ext Unit"); return 8;
+		case MIXER_UNIT:
+			strcpy(name, "Mixer"); return 5;
+		default:
+			return sprintf(name, "Unit %d", iterm->id);
+		}
+	}
+
+	switch (iterm->type & 0xff00) {
+	case 0x0100:
+		strcpy(name, "PCM"); return 3;
+	case 0x0200:
+		strcpy(name, "Mic"); return 3;
+	case 0x0400:
+		strcpy(name, "Headset"); return 7;
+	case 0x0500:
+		strcpy(name, "Phone"); return 5;
+	}
+
+	for (names = iterm_names; names->type; names++)
+		if (names->type == iterm->type) {
+			strcpy(name, names->name);
+			return strlen(names->name);
+		}
+	return 0;
+}
+
+
+/*
+ * parse the source unit recursively until it reaches to a terminal
+ * or a branched unit.
+ */
+static int check_input_term(mixer_build_t *state, int id, usb_audio_term_t *term)
+{
+	unsigned char *p1;
+
+	memset(term, 0, sizeof(*term));
+	while ((p1 = find_audio_control_unit(state, id)) != NULL) {
+		term->id = id;
+		switch (p1[2]) {
+		case INPUT_TERMINAL:
+			term->type = combine_word(p1 + 4);
+			term->channels = p1[7];
+			term->chconfig = combine_word(p1 + 8);
+			term->name = p1[11];
+			return 0;
+		case FEATURE_UNIT:
+			id = p1[4];
+			break; /* continue to parse */
+		case MIXER_UNIT:
+			term->type = p1[2] << 16; /* virtual type */
+			term->channels = p1[5 + p1[4]];
+			term->chconfig = combine_word(p1 + 6 + p1[4]);
+			term->name = p1[p1[0] - 1];
+			return 0;
+		case SELECTOR_UNIT:
+			/* call recursively to retrieve the channel info */
+			if (check_input_term(state, p1[5], term) < 0)
+				return -ENODEV;
+			term->type = p1[2] << 16; /* virtual type */
+			term->id = id;
+			term->name = p1[9 + p1[0] - 1];
+			return 0;
+		case PROCESSING_UNIT:
+		case EXTENSION_UNIT:
+			if (p1[6] == 1) {
+				id = p1[7];
+				break; /* continue to parse */
+			}
+			term->type = p1[2] << 16; /* virtual type */
+			term->channels = p1[7 + p1[6]];
+			term->chconfig = combine_word(p1 + 8 + p1[6]);
+			term->name = p1[12 + p1[6] + p1[11 + p1[6]]];
+			return 0;
+		default:
+			return -ENODEV;
+		}
+	}
+	return -ENODEV;
+}
+
+
+/*
+ * Feature Unit
+ */
+
+/* feature unit control information */
+struct usb_feature_control_info {
+	const char *name;
+	unsigned int type;	/* control type (mute, volume, etc.) */
+};
+
+static struct usb_feature_control_info audio_feature_info[] = {
+	{ "Mute",		USB_MIXER_INV_BOOLEAN },
+	{ "Volume",		USB_MIXER_S16 },
+	{ "Tone Control - Bass",	USB_MIXER_S8 },
+	{ "Tone Control - Mid",		USB_MIXER_S8 },
+	{ "Tone Control - Treble",	USB_MIXER_S8 },
+	{ "Graphic Equalizer",		USB_MIXER_S8 }, /* FIXME: not implemeted yet */
+	{ "Auto Gain Control",	USB_MIXER_BOOLEAN },
+	{ "Delay Control",	USB_MIXER_U16 },
+	{ "Bass Boost",		USB_MIXER_BOOLEAN },
+	{ "Loudness",		USB_MIXER_BOOLEAN },
+};
+
+
+/* private_free callback */
+static void usb_mixer_elem_free(snd_kcontrol_t *kctl)
+{
+	if (kctl->private_data) {
+		kfree(kctl->private_data);
+		kctl->private_data = NULL;
+	}
+}
+
+
+/*
+ * interface to ALSA control for feature/mixer units
+ */
+
+/*
+ * retrieve the minimum and maximum values for the specified control
+ */
+static int get_min_max(usb_mixer_elem_info_t *cval, int default_min)
+{
+	/* for failsafe */
+	cval->min = default_min;
+	cval->max = cval->min + 1;
+	cval->res = 1;
+
+	if (cval->val_type == USB_MIXER_BOOLEAN ||
+	    cval->val_type == USB_MIXER_INV_BOOLEAN) {
+		cval->initialized = 1;
+	} else {
+		int minchn = 0;
+		if (cval->cmask) {
+			int i;
+			for (i = 0; i < MAX_CHANNELS; i++)
+				if (cval->cmask & (1 << i)) {
+					minchn = i + 1;
+					break;
+				}
+		}
+		if (get_ctl_value(cval, GET_MAX, (cval->control << 8) | minchn, &cval->max) < 0 ||
+		    get_ctl_value(cval, GET_MIN, (cval->control << 8) | minchn, &cval->min) < 0) {
+			snd_printd(KERN_ERR "%d:%d: cannot get min/max values for control %d (id %d)\n", cval->id, cval->ctrlif, cval->control, cval->id);
+			return -EINVAL;
+		}
+		if (get_ctl_value(cval, GET_RES, (cval->control << 8) | minchn, &cval->res) < 0) {
+			cval->res = 1;
+		} else {
+			int last_valid_res = cval->res;
+
+			while (cval->res > 1) {
+				if (set_ctl_value(cval, SET_RES, (cval->control << 8) | minchn, cval->res / 2) < 0)
+					break;
+				cval->res /= 2;
+			}
+			if (get_ctl_value(cval, GET_RES, (cval->control << 8) | minchn, &cval->res) < 0)
+				cval->res = last_valid_res;
+		}
+		if (cval->res == 0)
+			cval->res = 1;
+		cval->initialized = 1;
+	}
+	return 0;
+}
+
+
+/* get a feature/mixer unit info */
+static int mixer_ctl_feature_info(snd_kcontrol_t *kcontrol, snd_ctl_elem_info_t *uinfo)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+
+	if (cval->val_type == USB_MIXER_BOOLEAN ||
+	    cval->val_type == USB_MIXER_INV_BOOLEAN)
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	else
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = cval->channels;
+	if (cval->val_type == USB_MIXER_BOOLEAN ||
+	    cval->val_type == USB_MIXER_INV_BOOLEAN) {
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = 1;
+	} else {
+		if (! cval->initialized)
+			get_min_max(cval,  0);
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = (cval->max - cval->min) / cval->res;
+	}
+	return 0;
+}
+
+/* get the current value from feature/mixer unit */
+static int mixer_ctl_feature_get(snd_kcontrol_t *kcontrol, snd_ctl_elem_value_t *ucontrol)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	int c, cnt, val, err;
+
+	if (cval->cmask) {
+		cnt = 0;
+		for (c = 0; c < MAX_CHANNELS; c++) {
+			if (cval->cmask & (1 << c)) {
+				err = get_cur_mix_value(cval, c + 1, &val);
+				if (err < 0) {
+					if (cval->chip->ignore_ctl_error) {
+						ucontrol->value.integer.value[0] = cval->min;
+						return 0;
+					}
+					snd_printd(KERN_ERR "cannot get current value for control %d ch %d: err = %d\n", cval->control, c + 1, err);
+					return err;
+				}
+				val = get_relative_value(cval, val);
+				ucontrol->value.integer.value[cnt] = val;
+				cnt++;
+			}
+		}
+	} else {
+		/* master channel */
+		err = get_cur_mix_value(cval, 0, &val);
+		if (err < 0) {
+			if (cval->chip->ignore_ctl_error) {
+				ucontrol->value.integer.value[0] = cval->min;
+				return 0;
+			}
+			snd_printd(KERN_ERR "cannot get current value for control %d master ch: err = %d\n", cval->control, err);
+			return err;
+		}
+		val = get_relative_value(cval, val);
+		ucontrol->value.integer.value[0] = val;
+	}
+	return 0;
+}
+
+/* put the current value to feature/mixer unit */
+static int mixer_ctl_feature_put(snd_kcontrol_t *kcontrol, snd_ctl_elem_value_t *ucontrol)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	int c, cnt, val, oval, err;
+	int changed = 0;
+
+	if (cval->cmask) {
+		cnt = 0;
+		for (c = 0; c < MAX_CHANNELS; c++) {
+			if (cval->cmask & (1 << c)) {
+				err = get_cur_mix_value(cval, c + 1, &oval);
+				if (err < 0) {
+					if (cval->chip->ignore_ctl_error)
+						return 0;
+					return err;
+				}
+				val = ucontrol->value.integer.value[cnt];
+				val = get_abs_value(cval, val);
+				if (oval != val) {
+					set_cur_mix_value(cval, c + 1, val);
+					changed = 1;
+				}
+				get_cur_mix_value(cval, c + 1, &val);
+				cnt++;
+			}
+		}
+	} else {
+		/* master channel */
+		err = get_cur_mix_value(cval, 0, &oval);
+		if (err < 0 && cval->chip->ignore_ctl_error)
+			return 0;
+		if (err < 0)
+			return err;
+		val = ucontrol->value.integer.value[0];
+		val = get_abs_value(cval, val);
+		if (val != oval) {
+			set_cur_mix_value(cval, 0, val);
+			changed = 1;
+		}
+	}
+	return changed;
+}
+
+static snd_kcontrol_new_t usb_feature_unit_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later manually */
+	.info = mixer_ctl_feature_info,
+	.get = mixer_ctl_feature_get,
+	.put = mixer_ctl_feature_put,
+};
+
+
+/*
+ * build a feature control
+ */
+
+static void build_feature_ctl(mixer_build_t *state, unsigned char *desc,
+			      unsigned int ctl_mask, int control,
+			      usb_audio_term_t *iterm, int unitid)
+{
+	unsigned int len = 0;
+	int mapped_name = 0;
+	int nameid = desc[desc[0] - 1];
+	snd_kcontrol_t *kctl;
+	usb_mixer_elem_info_t *cval;
+
+	control++; /* change from zero-based to 1-based value */
+
+	if (control == USB_FEATURE_GEQ) {
+		/* FIXME: not supported yet */
+		return;
+	}
+
+	if (check_ignored_ctl(state, unitid, control))
+		return;
+
+	cval = kcalloc(1, sizeof(*cval), GFP_KERNEL);
+	if (! cval) {
+		snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+		return;
+	}
+	cval->chip = state->chip;
+	cval->ctrlif = state->ctrlif;
+	cval->id = unitid;
+	cval->control = control;
+	cval->cmask = ctl_mask;
+	cval->val_type = audio_feature_info[control-1].type;
+	if (ctl_mask == 0)
+		cval->channels = 1;	/* master channel */
+	else {
+		int i, c = 0;
+		for (i = 0; i < 16; i++)
+			if (ctl_mask & (1 << i))
+				c++;
+		cval->channels = c;
+	}
+
+	/* get min/max values */
+	get_min_max(cval, 0);
+
+	kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
+	if (! kctl) {
+		snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+		kfree(cval);
+		return;
+	}
+	kctl->private_free = usb_mixer_elem_free;
+
+	len = check_mapped_name(state, unitid, control, kctl->id.name, sizeof(kctl->id.name));
+	mapped_name = len != 0;
+	if (! len && nameid)
+		len = snd_usb_copy_string_desc(state, nameid, kctl->id.name, sizeof(kctl->id.name));
+
+	switch (control) {
+	case USB_FEATURE_MUTE:
+	case USB_FEATURE_VOLUME:
+		/* determine the control name.  the rule is:
+		 * - if a name id is given in descriptor, use it.
+		 * - if the connected input can be determined, then use the name
+		 *   of terminal type.
+		 * - if the connected output can be determined, use it.
+		 * - otherwise, anonymous name.
+		 */
+		if (! len) {
+			len = get_term_name(state, iterm, kctl->id.name, sizeof(kctl->id.name), 1);
+			if (! len)
+				len = get_term_name(state, &state->oterm, kctl->id.name, sizeof(kctl->id.name), 1);
+			if (! len)
+				len = snprintf(kctl->id.name, sizeof(kctl->id.name),
+					       "Feature %d", unitid);
+		}
+		/* determine the stream direction:
+		 * if the connected output is USB stream, then it's likely a
+		 * capture stream.  otherwise it should be playback (hopefully :)
+		 */
+		if (! mapped_name && ! (state->oterm.type >> 16)) {
+			if ((state->oterm.type & 0xff00) == 0x0100) {
+				len = strlcat(kctl->id.name, " Capture", sizeof(kctl->id.name));
+			} else {
+				len = strlcat(kctl->id.name + len, " Playback", sizeof(kctl->id.name));
+			}
+		}
+		strlcat(kctl->id.name + len, control == USB_FEATURE_MUTE ? " Switch" : " Volume",
+			sizeof(kctl->id.name));
+		break;
+
+	default:
+		if (! len)
+			strlcpy(kctl->id.name, audio_feature_info[control-1].name,
+				sizeof(kctl->id.name));
+		break;
+	}
+
+	/* quirk for UDA1321/N101 */
+	/* note that detection between firmware 2.1.1.7 (N101) and later 2.1.1.21 */
+	/* is not very clear from datasheets */
+	/* I hope that the min value is -15360 for newer firmware --jk */
+	if (((state->vendor == 0x471 && (state->product == 0x104 || state->product == 0x105 || state->product == 0x101)) ||
+	     (state->vendor == 0x672 && state->product == 0x1041)) && !strcmp(kctl->id.name, "PCM Playback Volume") &&
+	     cval->min == -15616) {
+		snd_printk("USB Audio: using volume control quirk for the UDA1321/N101 chip\n");
+		cval->max = -256;
+	}
+
+	snd_printdd(KERN_INFO "[%d] FU [%s] ch = %d, val = %d/%d/%d\n",
+		    cval->id, kctl->id.name, cval->channels, cval->min, cval->max, cval->res);
+	add_control_to_empty(state->chip->card, kctl);
+}
+
+
+
+/*
+ * parse a feature unit
+ *
+ * most of controlls are defined here.
+ */
+static int parse_audio_feature_unit(mixer_build_t *state, int unitid, unsigned char *ftr)
+{
+	int channels, i, j;
+	usb_audio_term_t iterm;
+	unsigned int master_bits, first_ch_bits;
+	int err, csize;
+
+	if (ftr[0] < 7 || ! (csize = ftr[5]) || ftr[0] < 7 + csize) {
+		snd_printk(KERN_ERR "usbaudio: unit %u: invalid FEATURE_UNIT descriptor\n", unitid);
+		return -EINVAL;
+	}
+
+	/* parse the source unit */
+	if ((err = parse_audio_unit(state, ftr[4])) < 0)
+		return err;
+
+	/* determine the input source type and name */
+	if (check_input_term(state, ftr[4], &iterm) < 0)
+		return -EINVAL;
+
+	channels = (ftr[0] - 7) / csize - 1;
+
+	master_bits = snd_usb_combine_bytes(ftr + 6, csize);
+	if (channels > 0)
+		first_ch_bits = snd_usb_combine_bytes(ftr + 6 + csize, csize);
+	else
+		first_ch_bits = 0;
+	/* check all control types */
+	for (i = 0; i < 10; i++) {
+		unsigned int ch_bits = 0;
+		for (j = 0; j < channels; j++) {
+			unsigned int mask = snd_usb_combine_bytes(ftr + 6 + csize * (j+1), csize);
+			if (mask & (1 << i))
+				ch_bits |= (1 << j);
+		}
+		if (ch_bits & 1) /* the first channel must be set (for ease of programming) */
+			build_feature_ctl(state, ftr, ch_bits, i, &iterm, unitid);
+		if (master_bits & (1 << i))
+			build_feature_ctl(state, ftr, 0, i, &iterm, unitid);
+	}
+
+	return 0;
+}
+
+
+/*
+ * Mixer Unit
+ */
+
+/*
+ * build a mixer unit control
+ *
+ * the callbacks are identical with feature unit.
+ * input channel number (zero based) is given in control field instead.
+ */
+
+static void build_mixer_unit_ctl(mixer_build_t *state, unsigned char *desc,
+				 int in_pin, int in_ch, int unitid,
+				 usb_audio_term_t *iterm)
+{
+	usb_mixer_elem_info_t *cval;
+	unsigned int input_pins = desc[4];
+	unsigned int num_outs = desc[5 + input_pins];
+	unsigned int i, len;
+	snd_kcontrol_t *kctl;
+
+	if (check_ignored_ctl(state, unitid, 0))
+		return;
+
+	cval = kcalloc(1, sizeof(*cval), GFP_KERNEL);
+	if (! cval)
+		return;
+
+	cval->chip = state->chip;
+	cval->ctrlif = state->ctrlif;
+	cval->id = unitid;
+	cval->control = in_ch + 1; /* based on 1 */
+	cval->val_type = USB_MIXER_S16;
+	for (i = 0; i < num_outs; i++) {
+		if (check_matrix_bitmap(desc + 9 + input_pins, in_ch, i, num_outs)) {
+			cval->cmask |= (1 << i);
+			cval->channels++;
+		}
+	}
+
+	/* get min/max values */
+	get_min_max(cval, 0);
+
+	kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
+	if (! kctl) {
+		snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+		kfree(cval);
+		return;
+	}
+	kctl->private_free = usb_mixer_elem_free;
+
+	len = check_mapped_name(state, unitid, 0, kctl->id.name, sizeof(kctl->id.name));
+	if (! len)
+		len = get_term_name(state, iterm, kctl->id.name, sizeof(kctl->id.name), 0);
+	if (! len)
+		len = sprintf(kctl->id.name, "Mixer Source %d", in_ch + 1);
+	strlcat(kctl->id.name + len, " Volume", sizeof(kctl->id.name));
+
+	snd_printdd(KERN_INFO "[%d] MU [%s] ch = %d, val = %d/%d\n",
+		    cval->id, kctl->id.name, cval->channels, cval->min, cval->max);
+	add_control_to_empty(state->chip->card, kctl);
+}
+
+
+/*
+ * parse a mixer unit
+ */
+static int parse_audio_mixer_unit(mixer_build_t *state, int unitid, unsigned char *desc)
+{
+	usb_audio_term_t iterm;
+	int input_pins, num_ins, num_outs;
+	int pin, ich, err;
+
+	if (desc[0] < 11 || ! (input_pins = desc[4]) || ! (num_outs = desc[5 + input_pins])) {
+		snd_printk(KERN_ERR "invalid MIXER UNIT descriptor %d\n", unitid);
+		return -EINVAL;
+	}
+	/* no bmControls field (e.g. Maya44) -> ignore */
+	if (desc[0] <= 10 + input_pins) {
+		snd_printdd(KERN_INFO "MU %d has no bmControls field\n", unitid);
+		return 0;
+	}
+
+	num_ins = 0;
+	ich = 0;
+	for (pin = 0; pin < input_pins; pin++) {
+		err = parse_audio_unit(state, desc[5 + pin]);
+		if (err < 0)
+			return err;
+		err = check_input_term(state, desc[5 + pin], &iterm);
+		if (err < 0)
+			return err;
+		num_ins += iterm.channels;
+		for (; ich < num_ins; ++ich) {
+			int och, ich_has_controls = 0;
+
+			for (och = 0; och < num_outs; ++och) {
+				if (check_matrix_bitmap(desc + 9 + input_pins,
+							ich, och, num_outs)) {
+					ich_has_controls = 1;
+					break;
+				}
+			}
+			if (ich_has_controls)
+				build_mixer_unit_ctl(state, desc, pin, ich,
+						     unitid, &iterm);
+		}
+	}
+	return 0;
+}
+
+
+/*
+ * Processing Unit / Extension Unit
+ */
+
+/* get callback for processing/extension unit */
+static int mixer_ctl_procunit_get(snd_kcontrol_t *kcontrol, snd_ctl_elem_value_t *ucontrol)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	int err, val;
+
+	err = get_cur_ctl_value(cval, cval->control << 8, &val);
+	if (err < 0 && cval->chip->ignore_ctl_error) {
+		ucontrol->value.integer.value[0] = cval->min;
+		return 0;
+	}
+	if (err < 0)
+		return err;
+	val = get_relative_value(cval, val);
+	ucontrol->value.integer.value[0] = val;
+	return 0;
+}
+
+/* put callback for processing/extension unit */
+static int mixer_ctl_procunit_put(snd_kcontrol_t *kcontrol, snd_ctl_elem_value_t *ucontrol)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	int val, oval, err;
+
+	err = get_cur_ctl_value(cval, cval->control << 8, &oval);
+	if (err < 0) {
+		if (cval->chip->ignore_ctl_error)
+			return 0;
+		return err;
+	}
+	val = ucontrol->value.integer.value[0];
+	val = get_abs_value(cval, val);
+	if (val != oval) {
+		set_cur_ctl_value(cval, cval->control << 8, val);
+		return 1;
+	}
+	return 0;
+}
+
+/* alsa control interface for processing/extension unit */
+static snd_kcontrol_new_t mixer_procunit_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later */
+	.info = mixer_ctl_feature_info,
+	.get = mixer_ctl_procunit_get,
+	.put = mixer_ctl_procunit_put,
+};
+
+
+/*
+ * predefined data for processing units
+ */
+struct procunit_value_info {
+	int control;
+	char *suffix;
+	int val_type;
+	int min_value;
+};
+
+struct procunit_info {
+	int type;
+	char *name;
+	struct procunit_value_info *values;
+};
+
+static struct procunit_value_info updown_proc_info[] = {
+	{ USB_PROC_UPDOWN_SWITCH, "Switch", USB_MIXER_BOOLEAN },
+	{ USB_PROC_UPDOWN_MODE_SEL, "Mode Select", USB_MIXER_U8, 1 },
+	{ 0 }
+};
+static struct procunit_value_info prologic_proc_info[] = {
+	{ USB_PROC_PROLOGIC_SWITCH, "Switch", USB_MIXER_BOOLEAN },
+	{ USB_PROC_PROLOGIC_MODE_SEL, "Mode Select", USB_MIXER_U8, 1 },
+	{ 0 }
+};
+static struct procunit_value_info threed_enh_proc_info[] = {
+	{ USB_PROC_3DENH_SWITCH, "Switch", USB_MIXER_BOOLEAN },
+	{ USB_PROC_3DENH_SPACE, "Spaciousness", USB_MIXER_U8 },
+	{ 0 }
+};
+static struct procunit_value_info reverb_proc_info[] = {
+	{ USB_PROC_REVERB_SWITCH, "Switch", USB_MIXER_BOOLEAN },
+	{ USB_PROC_REVERB_LEVEL, "Level", USB_MIXER_U8 },
+	{ USB_PROC_REVERB_TIME, "Time", USB_MIXER_U16 },
+	{ USB_PROC_REVERB_DELAY, "Delay", USB_MIXER_U8 },
+	{ 0 }
+};
+static struct procunit_value_info chorus_proc_info[] = {
+	{ USB_PROC_CHORUS_SWITCH, "Switch", USB_MIXER_BOOLEAN },
+	{ USB_PROC_CHORUS_LEVEL, "Level", USB_MIXER_U8 },
+	{ USB_PROC_CHORUS_RATE, "Rate", USB_MIXER_U16 },
+	{ USB_PROC_CHORUS_DEPTH, "Depth", USB_MIXER_U16 },
+	{ 0 }
+};
+static struct procunit_value_info dcr_proc_info[] = {
+	{ USB_PROC_DCR_SWITCH, "Switch", USB_MIXER_BOOLEAN },
+	{ USB_PROC_DCR_RATIO, "Ratio", USB_MIXER_U16 },
+	{ USB_PROC_DCR_MAX_AMP, "Max Amp", USB_MIXER_S16 },
+	{ USB_PROC_DCR_THRESHOLD, "Threshold", USB_MIXER_S16 },
+	{ USB_PROC_DCR_ATTACK, "Attack Time", USB_MIXER_U16 },
+	{ USB_PROC_DCR_RELEASE, "Release Time", USB_MIXER_U16 },
+	{ 0 }
+};
+
+static struct procunit_info procunits[] = {
+	{ USB_PROC_UPDOWN, "Up Down", updown_proc_info },
+	{ USB_PROC_PROLOGIC, "Dolby Prologic", prologic_proc_info },
+	{ USB_PROC_3DENH, "3D Stereo Extender", threed_enh_proc_info },
+	{ USB_PROC_REVERB, "Reverb", reverb_proc_info },
+	{ USB_PROC_CHORUS, "Chorus", chorus_proc_info },
+	{ USB_PROC_DCR, "DCR", dcr_proc_info },
+	{ 0 },
+};
+
+/*
+ * build a processing/extension unit
+ */
+static int build_audio_procunit(mixer_build_t *state, int unitid, unsigned char *dsc, struct procunit_info *list, char *name)
+{
+	int num_ins = dsc[6];
+	usb_mixer_elem_info_t *cval;
+	snd_kcontrol_t *kctl;
+	int i, err, nameid, type, len;
+	struct procunit_info *info;
+	struct procunit_value_info *valinfo;
+	static struct procunit_value_info default_value_info[] = {
+		{ 0x01, "Switch", USB_MIXER_BOOLEAN },
+		{ 0 }
+	};
+	static struct procunit_info default_info = {
+		0, NULL, default_value_info
+	};
+
+	if (dsc[0] < 13 || dsc[0] < 13 + num_ins || dsc[0] < num_ins + dsc[11 + num_ins]) {
+		snd_printk(KERN_ERR "invalid %s descriptor (id %d)\n", name, unitid);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num_ins; i++) {
+		if ((err = parse_audio_unit(state, dsc[7 + i])) < 0)
+			return err;
+	}
+
+	type = combine_word(&dsc[4]);
+	if (! type)
+		return 0; /* undefined? */
+
+	for (info = list; info && info->type; info++)
+		if (info->type == type)
+			break;
+	if (! info || ! info->type)
+		info = &default_info;
+
+	for (valinfo = info->values; valinfo->control; valinfo++) {
+		/* FIXME: bitmap might be longer than 8bit */
+		if (! (dsc[12 + num_ins] & (1 << (valinfo->control - 1))))
+			continue;
+		if (check_ignored_ctl(state, unitid, valinfo->control))
+			continue;
+		cval = kcalloc(1, sizeof(*cval), GFP_KERNEL);
+		if (! cval) {
+			snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+			return -ENOMEM;
+		}
+		cval->chip = state->chip;
+		cval->ctrlif = state->ctrlif;
+		cval->id = unitid;
+		cval->control = valinfo->control;
+		cval->val_type = valinfo->val_type;
+		cval->channels = 1;
+
+		/* get min/max values */
+		if (type == USB_PROC_UPDOWN && cval->control == USB_PROC_UPDOWN_MODE_SEL) {
+			/* FIXME: hard-coded */
+			cval->min = 1;
+			cval->max = dsc[15];
+			cval->res = 1;
+			cval->initialized = 1;
+		} else
+			get_min_max(cval, valinfo->min_value);
+
+		kctl = snd_ctl_new1(&mixer_procunit_ctl, cval);
+		if (! kctl) {
+			snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+			kfree(cval);
+			return -ENOMEM;
+		}
+		kctl->private_free = usb_mixer_elem_free;
+
+		if (check_mapped_name(state, unitid, cval->control, kctl->id.name, sizeof(kctl->id.name)))
+			;
+		else if (info->name)
+			strlcpy(kctl->id.name, info->name, sizeof(kctl->id.name));
+		else {
+			nameid = dsc[12 + num_ins + dsc[11 + num_ins]];
+			len = 0;
+			if (nameid)
+				len = snd_usb_copy_string_desc(state, nameid, kctl->id.name, sizeof(kctl->id.name));
+			if (! len)
+				strlcpy(kctl->id.name, name, sizeof(kctl->id.name));
+		}
+		strlcat(kctl->id.name, " ", sizeof(kctl->id.name));
+		strlcat(kctl->id.name, valinfo->suffix, sizeof(kctl->id.name));
+
+		snd_printdd(KERN_INFO "[%d] PU [%s] ch = %d, val = %d/%d\n",
+			    cval->id, kctl->id.name, cval->channels, cval->min, cval->max);
+		if ((err = add_control_to_empty(state->chip->card, kctl)) < 0)
+			return err;
+	}
+	return 0;
+}
+
+
+static int parse_audio_processing_unit(mixer_build_t *state, int unitid, unsigned char *desc)
+{
+	return build_audio_procunit(state, unitid, desc, procunits, "Processing Unit");
+}
+
+static int parse_audio_extension_unit(mixer_build_t *state, int unitid, unsigned char *desc)
+{
+	return build_audio_procunit(state, unitid, desc, NULL, "Extension Unit");
+}
+
+
+/*
+ * Selector Unit
+ */
+
+/* info callback for selector unit
+ * use an enumerator type for routing
+ */
+static int mixer_ctl_selector_info(snd_kcontrol_t *kcontrol, snd_ctl_elem_info_t *uinfo)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	char **itemlist = (char **)kcontrol->private_value;
+
+	snd_assert(itemlist, return -EINVAL);
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+	uinfo->count = 1;
+	uinfo->value.enumerated.items = cval->max;
+	if ((int)uinfo->value.enumerated.item >= cval->max)
+		uinfo->value.enumerated.item = cval->max - 1;
+	strcpy(uinfo->value.enumerated.name, itemlist[uinfo->value.enumerated.item]);
+	return 0;
+}
+
+/* get callback for selector unit */
+static int mixer_ctl_selector_get(snd_kcontrol_t *kcontrol, snd_ctl_elem_value_t *ucontrol)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	int val, err;
+
+	err = get_cur_ctl_value(cval, 0, &val);
+	if (err < 0) {
+		if (cval->chip->ignore_ctl_error) {
+			ucontrol->value.enumerated.item[0] = 0;
+			return 0;
+		}
+		return err;
+	}
+	val = get_relative_value(cval, val);
+	ucontrol->value.enumerated.item[0] = val;
+	return 0;
+}
+
+/* put callback for selector unit */
+static int mixer_ctl_selector_put(snd_kcontrol_t *kcontrol, snd_ctl_elem_value_t *ucontrol)
+{
+	usb_mixer_elem_info_t *cval = kcontrol->private_data;
+	int val, oval, err;
+
+	err = get_cur_ctl_value(cval, 0, &oval);
+	if (err < 0) {
+		if (cval->chip->ignore_ctl_error)
+			return 0;
+		return err;
+	}
+	val = ucontrol->value.enumerated.item[0];
+	val = get_abs_value(cval, val);
+	if (val != oval) {
+		set_cur_ctl_value(cval, 0, val);
+		return 1;
+	}
+	return 0;
+}
+
+/* alsa control interface for selector unit */
+static snd_kcontrol_new_t mixer_selectunit_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later */
+	.info = mixer_ctl_selector_info,
+	.get = mixer_ctl_selector_get,
+	.put = mixer_ctl_selector_put,
+};
+
+
+/* private free callback.
+ * free both private_data and private_value
+ */
+static void usb_mixer_selector_elem_free(snd_kcontrol_t *kctl)
+{
+	int i, num_ins = 0;
+
+	if (kctl->private_data) {
+		usb_mixer_elem_info_t *cval = kctl->private_data;
+		num_ins = cval->max;
+		kfree(cval);
+		kctl->private_data = NULL;
+	}
+	if (kctl->private_value) {
+		char **itemlist = (char **)kctl->private_value;
+		for (i = 0; i < num_ins; i++)
+			kfree(itemlist[i]);
+		kfree(itemlist);
+		kctl->private_value = 0;
+	}
+}
+
+/*
+ * parse a selector unit
+ */
+static int parse_audio_selector_unit(mixer_build_t *state, int unitid, unsigned char *desc)
+{
+	unsigned int num_ins = desc[4];
+	unsigned int i, nameid, len;
+	int err;
+	usb_mixer_elem_info_t *cval;
+	snd_kcontrol_t *kctl;
+	char **namelist;
+
+	if (! num_ins || desc[0] < 6 + num_ins) {
+		snd_printk(KERN_ERR "invalid SELECTOR UNIT descriptor %d\n", unitid);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num_ins; i++) {
+		if ((err = parse_audio_unit(state, desc[5 + i])) < 0)
+			return err;
+	}
+
+	if (num_ins == 1) /* only one ? nonsense! */
+		return 0;
+
+	if (check_ignored_ctl(state, unitid, 0))
+		return 0;
+
+	cval = kcalloc(1, sizeof(*cval), GFP_KERNEL);
+	if (! cval) {
+		snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+		return -ENOMEM;
+	}
+	cval->chip = state->chip;
+	cval->ctrlif = state->ctrlif;
+	cval->id = unitid;
+	cval->val_type = USB_MIXER_U8;
+	cval->channels = 1;
+	cval->min = 1;
+	cval->max = num_ins;
+	cval->res = 1;
+	cval->initialized = 1;
+
+	namelist = kmalloc(sizeof(char *) * num_ins, GFP_KERNEL);
+	if (! namelist) {
+		snd_printk(KERN_ERR "cannot malloc\n");
+		kfree(cval);
+		return -ENOMEM;
+	}
+#define MAX_ITEM_NAME_LEN	64
+	for (i = 0; i < num_ins; i++) {
+		usb_audio_term_t iterm;
+		len = 0;
+		namelist[i] = kmalloc(MAX_ITEM_NAME_LEN, GFP_KERNEL);
+		if (! namelist[i]) {
+			snd_printk(KERN_ERR "cannot malloc\n");
+			while (--i > 0)
+				kfree(namelist[i]);
+			kfree(namelist);
+			kfree(cval);
+			return -ENOMEM;
+		}
+		if (check_input_term(state, desc[5 + i], &iterm) >= 0)
+			len = get_term_name(state, &iterm, namelist[i], MAX_ITEM_NAME_LEN, 0);
+		if (! len)
+			sprintf(namelist[i], "Input %d", i);
+	}
+
+	kctl = snd_ctl_new1(&mixer_selectunit_ctl, cval);
+	if (! kctl) {
+		snd_printk(KERN_ERR "cannot malloc kcontrol\n");
+		kfree(cval);
+		return -ENOMEM;
+	}
+	kctl->private_value = (unsigned long)namelist;
+	kctl->private_free = usb_mixer_selector_elem_free;
+
+	nameid = desc[desc[0] - 1];
+	len = check_mapped_name(state, unitid, 0, kctl->id.name, sizeof(kctl->id.name));
+	if (len)
+		;
+	else if (nameid)
+		snd_usb_copy_string_desc(state, nameid, kctl->id.name, sizeof(kctl->id.name));
+	else {
+		len = get_term_name(state, &state->oterm,
+				    kctl->id.name, sizeof(kctl->id.name), 0);
+		if (! len)
+			strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
+
+		if ((state->oterm.type & 0xff00) == 0x0100)
+			strlcat(kctl->id.name, " Capture Source", sizeof(kctl->id.name));
+		else
+			strlcat(kctl->id.name, " Playback Source", sizeof(kctl->id.name));
+	}
+
+	snd_printdd(KERN_INFO "[%d] SU [%s] items = %d\n",
+		    cval->id, kctl->id.name, num_ins);
+	if ((err = add_control_to_empty(state->chip->card, kctl)) < 0)
+		return err;
+
+	return 0;
+}
+
+
+/*
+ * parse an audio unit recursively
+ */
+
+static int parse_audio_unit(mixer_build_t *state, int unitid)
+{
+	unsigned char *p1;
+
+	if (test_and_set_bit(unitid, state->unitbitmap))
+		return 0; /* the unit already visited */
+
+	p1 = find_audio_control_unit(state, unitid);
+	if (!p1) {
+		snd_printk(KERN_ERR "usbaudio: unit %d not found!\n", unitid);
+		return -EINVAL;
+	}
+
+	switch (p1[2]) {
+	case INPUT_TERMINAL:
+		return 0; /* NOP */
+	case MIXER_UNIT:
+		return parse_audio_mixer_unit(state, unitid, p1);
+	case SELECTOR_UNIT:
+		return parse_audio_selector_unit(state, unitid, p1);
+	case FEATURE_UNIT:
+		return parse_audio_feature_unit(state, unitid, p1);
+	case PROCESSING_UNIT:
+		return parse_audio_processing_unit(state, unitid, p1);
+	case EXTENSION_UNIT:
+		return parse_audio_extension_unit(state, unitid, p1);
+	default:
+		snd_printk(KERN_ERR "usbaudio: unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
+		return -EINVAL;
+	}
+}
+
+/*
+ * create mixer controls
+ *
+ * walk through all OUTPUT_TERMINAL descriptors to search for mixers
+ */
+int snd_usb_create_mixer(snd_usb_audio_t *chip, int ctrlif)
+{
+	unsigned char *desc;
+	mixer_build_t state;
+	int err;
+	const struct usbmix_ctl_map *map;
+	struct usb_device_descriptor *dev = &chip->dev->descriptor;
+	struct usb_host_interface *hostif = &usb_ifnum_to_if(chip->dev, ctrlif)->altsetting[0];
+
+	strcpy(chip->card->mixername, "USB Mixer");
+
+	memset(&state, 0, sizeof(state));
+	state.chip = chip;
+	state.buffer = hostif->extra;
+	state.buflen = hostif->extralen;
+	state.ctrlif = ctrlif;
+	state.vendor = le16_to_cpu(dev->idVendor);
+	state.product = le16_to_cpu(dev->idProduct);
+
+	/* check the mapping table */
+	for (map = usbmix_ctl_maps; map->vendor; map++) {
+		if (map->vendor == state.vendor && map->product == state.product) {
+			state.map = map->map;
+			chip->ignore_ctl_error = map->ignore_ctl_error;
+			break;
+		}
+	}
+#ifdef IGNORE_CTL_ERROR
+	chip->ignore_ctl_error = 1;
+#endif
+
+	desc = NULL;
+	while ((desc = snd_usb_find_csint_desc(hostif->extra, hostif->extralen, desc, OUTPUT_TERMINAL)) != NULL) {
+		if (desc[0] < 9)
+			continue; /* invalid descriptor? */
+		set_bit(desc[3], state.unitbitmap);  /* mark terminal ID as visited */
+		state.oterm.id = desc[3];
+		state.oterm.type = combine_word(&desc[4]);
+		state.oterm.name = desc[8];
+		err = parse_audio_unit(&state, desc[7]);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}