1 files changed, 731 insertions, 0 deletions

diff --git a/sound/usb/stream.c b/sound/usb/stream.c
new file mode 100644
index 000000000..310a3822d
--- /dev/null
+++ b/sound/usb/stream.c
@@ -0,0 +1,731 @@
+/*
+ *   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/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/control.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "proc.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "pcm.h"
+#include "helper.h"
+#include "format.h"
+#include "clock.h"
+#include "stream.h"
+
+/*
+ * free a substream
+ */
+static void free_substream(struct snd_usb_substream *subs)
+{
+	struct audioformat *fp, *n;
+
+	if (!subs->num_formats)
+		return; /* not initialized */
+	list_for_each_entry_safe(fp, n, &subs->fmt_list, list) {
+		kfree(fp->rate_table);
+		kfree(fp->chmap);
+		kfree(fp);
+	}
+	kfree(subs->rate_list.list);
+}
+
+
+/*
+ * free a usb stream instance
+ */
+static void snd_usb_audio_stream_free(struct snd_usb_stream *stream)
+{
+	free_substream(&stream->substream[0]);
+	free_substream(&stream->substream[1]);
+	list_del(&stream->list);
+	kfree(stream);
+}
+
+static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
+{
+	struct snd_usb_stream *stream = pcm->private_data;
+	if (stream) {
+		stream->pcm = NULL;
+		snd_usb_audio_stream_free(stream);
+	}
+}
+
+/*
+ * initialize the substream instance.
+ */
+
+static void snd_usb_init_substream(struct snd_usb_stream *as,
+				   int stream,
+				   struct audioformat *fp)
+{
+	struct snd_usb_substream *subs = &as->substream[stream];
+
+	INIT_LIST_HEAD(&subs->fmt_list);
+	spin_lock_init(&subs->lock);
+
+	subs->stream = as;
+	subs->direction = stream;
+	subs->dev = as->chip->dev;
+	subs->txfr_quirk = as->chip->txfr_quirk;
+	subs->speed = snd_usb_get_speed(subs->dev);
+	subs->pkt_offset_adj = 0;
+
+	snd_usb_set_pcm_ops(as->pcm, stream);
+
+	list_add_tail(&fp->list, &subs->fmt_list);
+	subs->formats |= fp->formats;
+	subs->num_formats++;
+	subs->fmt_type = fp->fmt_type;
+	subs->ep_num = fp->endpoint;
+	if (fp->channels > subs->channels_max)
+		subs->channels_max = fp->channels;
+}
+
+/* kctl callbacks for usb-audio channel maps */
+static int usb_chmap_ctl_info(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_info *uinfo)
+{
+	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_substream *subs = info->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = subs->channels_max;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SNDRV_CHMAP_LAST;
+	return 0;
+}
+
+/* check whether a duplicated entry exists in the audiofmt list */
+static bool have_dup_chmap(struct snd_usb_substream *subs,
+			   struct audioformat *fp)
+{
+	struct list_head *p;
+
+	for (p = fp->list.prev; p != &subs->fmt_list; p = p->prev) {
+		struct audioformat *prev;
+		prev = list_entry(p, struct audioformat, list);
+		if (prev->chmap &&
+		    !memcmp(prev->chmap, fp->chmap, sizeof(*fp->chmap)))
+			return true;
+	}
+	return false;
+}
+
+static int usb_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+			     unsigned int size, unsigned int __user *tlv)
+{
+	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_substream *subs = info->private_data;
+	struct audioformat *fp;
+	unsigned int __user *dst;
+	int count = 0;
+
+	if (size < 8)
+		return -ENOMEM;
+	if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
+		return -EFAULT;
+	size -= 8;
+	dst = tlv + 2;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		int i, ch_bytes;
+
+		if (!fp->chmap)
+			continue;
+		if (have_dup_chmap(subs, fp))
+			continue;
+		/* copy the entry */
+		ch_bytes = fp->chmap->channels * 4;
+		if (size < 8 + ch_bytes)
+			return -ENOMEM;
+		if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
+		    put_user(ch_bytes, dst + 1))
+			return -EFAULT;
+		dst += 2;
+		for (i = 0; i < fp->chmap->channels; i++, dst++) {
+			if (put_user(fp->chmap->map[i], dst))
+				return -EFAULT;
+		}
+
+		count += 8 + ch_bytes;
+		size -= 8 + ch_bytes;
+	}
+	if (put_user(count, tlv + 1))
+		return -EFAULT;
+	return 0;
+}
+
+static int usb_chmap_ctl_get(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_substream *subs = info->private_data;
+	struct snd_pcm_chmap_elem *chmap = NULL;
+	int i;
+
+	memset(ucontrol->value.integer.value, 0,
+	       sizeof(ucontrol->value.integer.value));
+	if (subs->cur_audiofmt)
+		chmap = subs->cur_audiofmt->chmap;
+	if (chmap) {
+		for (i = 0; i < chmap->channels; i++)
+			ucontrol->value.integer.value[i] = chmap->map[i];
+	}
+	return 0;
+}
+
+/* create a chmap kctl assigned to the given USB substream */
+static int add_chmap(struct snd_pcm *pcm, int stream,
+		     struct snd_usb_substream *subs)
+{
+	struct audioformat *fp;
+	struct snd_pcm_chmap *chmap;
+	struct snd_kcontrol *kctl;
+	int err;
+
+	list_for_each_entry(fp, &subs->fmt_list, list)
+		if (fp->chmap)
+			goto ok;
+	/* no chmap is found */
+	return 0;
+
+ ok:
+	err = snd_pcm_add_chmap_ctls(pcm, stream, NULL, 0, 0, &chmap);
+	if (err < 0)
+		return err;
+
+	/* override handlers */
+	chmap->private_data = subs;
+	kctl = chmap->kctl;
+	kctl->info = usb_chmap_ctl_info;
+	kctl->get = usb_chmap_ctl_get;
+	kctl->tlv.c = usb_chmap_ctl_tlv;
+
+	return 0;
+}
+
+/* convert from USB ChannelConfig bits to ALSA chmap element */
+static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
+						int protocol)
+{
+	static unsigned int uac1_maps[] = {
+		SNDRV_CHMAP_FL,		/* left front */
+		SNDRV_CHMAP_FR,		/* right front */
+		SNDRV_CHMAP_FC,		/* center front */
+		SNDRV_CHMAP_LFE,	/* LFE */
+		SNDRV_CHMAP_SL,		/* left surround */
+		SNDRV_CHMAP_SR,		/* right surround */
+		SNDRV_CHMAP_FLC,	/* left of center */
+		SNDRV_CHMAP_FRC,	/* right of center */
+		SNDRV_CHMAP_RC,		/* surround */
+		SNDRV_CHMAP_SL,		/* side left */
+		SNDRV_CHMAP_SR,		/* side right */
+		SNDRV_CHMAP_TC,		/* top */
+		0 /* terminator */
+	};
+	static unsigned int uac2_maps[] = {
+		SNDRV_CHMAP_FL,		/* front left */
+		SNDRV_CHMAP_FR,		/* front right */
+		SNDRV_CHMAP_FC,		/* front center */
+		SNDRV_CHMAP_LFE,	/* LFE */
+		SNDRV_CHMAP_RL,		/* back left */
+		SNDRV_CHMAP_RR,		/* back right */
+		SNDRV_CHMAP_FLC,	/* front left of center */
+		SNDRV_CHMAP_FRC,	/* front right of center */
+		SNDRV_CHMAP_RC,		/* back center */
+		SNDRV_CHMAP_SL,		/* side left */
+		SNDRV_CHMAP_SR,		/* side right */
+		SNDRV_CHMAP_TC,		/* top center */
+		SNDRV_CHMAP_TFL,	/* top front left */
+		SNDRV_CHMAP_TFC,	/* top front center */
+		SNDRV_CHMAP_TFR,	/* top front right */
+		SNDRV_CHMAP_TRL,	/* top back left */
+		SNDRV_CHMAP_TRC,	/* top back center */
+		SNDRV_CHMAP_TRR,	/* top back right */
+		SNDRV_CHMAP_TFLC,	/* top front left of center */
+		SNDRV_CHMAP_TFRC,	/* top front right of center */
+		SNDRV_CHMAP_LLFE,	/* left LFE */
+		SNDRV_CHMAP_RLFE,	/* right LFE */
+		SNDRV_CHMAP_TSL,	/* top side left */
+		SNDRV_CHMAP_TSR,	/* top side right */
+		SNDRV_CHMAP_BC,		/* bottom center */
+		SNDRV_CHMAP_RLC,	/* back left of center */
+		SNDRV_CHMAP_RRC,	/* back right of center */
+		0 /* terminator */
+	};
+	struct snd_pcm_chmap_elem *chmap;
+	const unsigned int *maps;
+	int c;
+
+	if (channels > ARRAY_SIZE(chmap->map))
+		return NULL;
+
+	chmap = kzalloc(sizeof(*chmap), GFP_KERNEL);
+	if (!chmap)
+		return NULL;
+
+	maps = protocol == UAC_VERSION_2 ? uac2_maps : uac1_maps;
+	chmap->channels = channels;
+	c = 0;
+
+	if (bits) {
+		for (; bits && *maps; maps++, bits >>= 1)
+			if (bits & 1)
+				chmap->map[c++] = *maps;
+	} else {
+		/* If we're missing wChannelConfig, then guess something
+		    to make sure the channel map is not skipped entirely */
+		if (channels == 1)
+			chmap->map[c++] = SNDRV_CHMAP_MONO;
+		else
+			for (; c < channels && *maps; maps++)
+				chmap->map[c++] = *maps;
+	}
+
+	for (; c < channels; c++)
+		chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
+
+	return chmap;
+}
+
+/*
+ * add this endpoint to the chip instance.
+ * if a stream with the same endpoint already exists, append to it.
+ * if not, create a new pcm stream.
+ */
+int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
+			     int stream,
+			     struct audioformat *fp)
+{
+	struct snd_usb_stream *as;
+	struct snd_usb_substream *subs;
+	struct snd_pcm *pcm;
+	int err;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		if (as->fmt_type != fp->fmt_type)
+			continue;
+		subs = &as->substream[stream];
+		if (subs->ep_num == fp->endpoint) {
+			list_add_tail(&fp->list, &subs->fmt_list);
+			subs->num_formats++;
+			subs->formats |= fp->formats;
+			return 0;
+		}
+	}
+	/* look for an empty stream */
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		if (as->fmt_type != fp->fmt_type)
+			continue;
+		subs = &as->substream[stream];
+		if (subs->ep_num)
+			continue;
+		err = snd_pcm_new_stream(as->pcm, stream, 1);
+		if (err < 0)
+			return err;
+		snd_usb_init_substream(as, stream, fp);
+		return add_chmap(as->pcm, stream, subs);
+	}
+
+	/* create a new pcm */
+	as = kzalloc(sizeof(*as), GFP_KERNEL);
+	if (!as)
+		return -ENOMEM;
+	as->pcm_index = chip->pcm_devs;
+	as->chip = chip;
+	as->fmt_type = fp->fmt_type;
+	err = snd_pcm_new(chip->card, "USB Audio", chip->pcm_devs,
+			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 1 : 0,
+			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1,
+			  &pcm);
+	if (err < 0) {
+		kfree(as);
+		return err;
+	}
+	as->pcm = pcm;
+	pcm->private_data = as;
+	pcm->private_free = snd_usb_audio_pcm_free;
+	pcm->info_flags = 0;
+	if (chip->pcm_devs > 0)
+		sprintf(pcm->name, "USB Audio #%d", chip->pcm_devs);
+	else
+		strcpy(pcm->name, "USB Audio");
+
+	snd_usb_init_substream(as, stream, fp);
+
+	list_add(&as->list, &chip->pcm_list);
+	chip->pcm_devs++;
+
+	snd_usb_proc_pcm_format_add(as);
+
+	return add_chmap(pcm, stream, &as->substream[stream]);
+}
+
+static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
+					 struct usb_host_interface *alts,
+					 int protocol, int iface_no)
+{
+	/* parsed with a v1 header here. that's ok as we only look at the
+	 * header first which is the same for both versions */
+	struct uac_iso_endpoint_descriptor *csep;
+	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
+	int attributes = 0;
+
+	csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
+
+	/* Creamware Noah has this descriptor after the 2nd endpoint */
+	if (!csep && altsd->bNumEndpoints >= 2)
+		csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
+
+	/*
+	 * If we can't locate the USB_DT_CS_ENDPOINT descriptor in the extra
+	 * bytes after the first endpoint, go search the entire interface.
+	 * Some devices have it directly *before* the standard endpoint.
+	 */
+	if (!csep)
+		csep = snd_usb_find_desc(alts->extra, alts->extralen, NULL, USB_DT_CS_ENDPOINT);
+
+	if (!csep || csep->bLength < 7 ||
+	    csep->bDescriptorSubtype != UAC_EP_GENERAL) {
+		usb_audio_warn(chip,
+			       "%u:%d : no or invalid class specific endpoint descriptor\n",
+			       iface_no, altsd->bAlternateSetting);
+		return 0;
+	}
+
+	if (protocol == UAC_VERSION_1) {
+		attributes = csep->bmAttributes;
+	} else {
+		struct uac2_iso_endpoint_descriptor *csep2 =
+			(struct uac2_iso_endpoint_descriptor *) csep;
+
+		attributes = csep->bmAttributes & UAC_EP_CS_ATTR_FILL_MAX;
+
+		/* emulate the endpoint attributes of a v1 device */
+		if (csep2->bmControls & UAC2_CONTROL_PITCH)
+			attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
+	}
+
+	return attributes;
+}
+
+/* find an input terminal descriptor (either UAC1 or UAC2) with the given
+ * terminal id
+ */
+static void *
+snd_usb_find_input_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+					       int terminal_id)
+{
+	struct uac2_input_terminal_descriptor *term = NULL;
+
+	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
+					       ctrl_iface->extralen,
+					       term, UAC_INPUT_TERMINAL))) {
+		if (term->bTerminalID == terminal_id)
+			return term;
+	}
+
+	return NULL;
+}
+
+static struct uac2_output_terminal_descriptor *
+	snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+						int terminal_id)
+{
+	struct uac2_output_terminal_descriptor *term = NULL;
+
+	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
+					       ctrl_iface->extralen,
+					       term, UAC_OUTPUT_TERMINAL))) {
+		if (term->bTerminalID == terminal_id)
+			return term;
+	}
+
+	return NULL;
+}
+
+int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
+{
+	struct usb_device *dev;
+	struct usb_interface *iface;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	int i, altno, err, stream;
+	unsigned int format = 0, num_channels = 0;
+	struct audioformat *fp = NULL;
+	int num, protocol, clock = 0;
+	struct uac_format_type_i_continuous_descriptor *fmt;
+	unsigned int chconfig;
+
+	dev = chip->dev;
+
+	/* parse the interface's altsettings */
+	iface = usb_ifnum_to_if(dev, iface_no);
+
+	num = iface->num_altsetting;
+
+	/*
+	 * Dallas DS4201 workaround: It presents 5 altsettings, but the last
+	 * one misses syncpipe, and does not produce any sound.
+	 */
+	if (chip->usb_id == USB_ID(0x04fa, 0x4201))
+		num = 4;
+
+	for (i = 0; i < num; i++) {
+		alts = &iface->altsetting[i];
+		altsd = get_iface_desc(alts);
+		protocol = altsd->bInterfaceProtocol;
+		/* skip invalid one */
+		if (((altsd->bInterfaceClass != USB_CLASS_AUDIO ||
+		      (altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING &&
+		       altsd->bInterfaceSubClass != USB_SUBCLASS_VENDOR_SPEC)) &&
+		     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
+		    altsd->bNumEndpoints < 1 ||
+		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == 0)
+			continue;
+		/* must be isochronous */
+		if ((get_endpoint(alts, 0)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
+		    USB_ENDPOINT_XFER_ISOC)
+			continue;
+		/* check direction */
+		stream = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN) ?
+			SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
+		altno = altsd->bAlternateSetting;
+
+		if (snd_usb_apply_interface_quirk(chip, iface_no, altno))
+			continue;
+
+		/*
+		 * Roland audio streaming interfaces are marked with protocols
+		 * 0/1/2, but are UAC 1 compatible.
+		 */
+		if (USB_ID_VENDOR(chip->usb_id) == 0x0582 &&
+		    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
+		    protocol <= 2)
+			protocol = UAC_VERSION_1;
+
+		chconfig = 0;
+		/* get audio formats */
+		switch (protocol) {
+		default:
+			dev_dbg(&dev->dev, "%u:%d: unknown interface protocol %#02x, assuming v1\n",
+				iface_no, altno, protocol);
+			protocol = UAC_VERSION_1;
+			/* fall through */
+
+		case UAC_VERSION_1: {
+			struct uac1_as_header_descriptor *as =
+				snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
+			struct uac_input_terminal_descriptor *iterm;
+
+			if (!as) {
+				dev_err(&dev->dev,
+					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
+					iface_no, altno);
+				continue;
+			}
+
+			if (as->bLength < sizeof(*as)) {
+				dev_err(&dev->dev,
+					"%u:%d : invalid UAC_AS_GENERAL desc\n",
+					iface_no, altno);
+				continue;
+			}
+
+			format = le16_to_cpu(as->wFormatTag); /* remember the format value */
+
+			iterm = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
+								       as->bTerminalLink);
+			if (iterm) {
+				num_channels = iterm->bNrChannels;
+				chconfig = le16_to_cpu(iterm->wChannelConfig);
+			}
+
+			break;
+		}
+
+		case UAC_VERSION_2: {
+			struct uac2_input_terminal_descriptor *input_term;
+			struct uac2_output_terminal_descriptor *output_term;
+			struct uac2_as_header_descriptor *as =
+				snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
+
+			if (!as) {
+				dev_err(&dev->dev,
+					"%u:%d : UAC_AS_GENERAL descriptor not found\n",
+					iface_no, altno);
+				continue;
+			}
+
+			if (as->bLength < sizeof(*as)) {
+				dev_err(&dev->dev,
+					"%u:%d : invalid UAC_AS_GENERAL desc\n",
+					iface_no, altno);
+				continue;
+			}
+
+			num_channels = as->bNrChannels;
+			format = le32_to_cpu(as->bmFormats);
+			chconfig = le32_to_cpu(as->bmChannelConfig);
+
+			/* lookup the terminal associated to this interface
+			 * to extract the clock */
+			input_term = snd_usb_find_input_terminal_descriptor(chip->ctrl_intf,
+									    as->bTerminalLink);
+			if (input_term) {
+				clock = input_term->bCSourceID;
+				if (!chconfig && (num_channels == input_term->bNrChannels))
+					chconfig = le32_to_cpu(input_term->bmChannelConfig);
+				break;
+			}
+
+			output_term = snd_usb_find_output_terminal_descriptor(chip->ctrl_intf,
+									      as->bTerminalLink);
+			if (output_term) {
+				clock = output_term->bCSourceID;
+				break;
+			}
+
+			dev_err(&dev->dev,
+				"%u:%d : bogus bTerminalLink %d\n",
+				iface_no, altno, as->bTerminalLink);
+			continue;
+		}
+		}
+
+		/* get format type */
+		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, UAC_FORMAT_TYPE);
+		if (!fmt) {
+			dev_err(&dev->dev,
+				"%u:%d : no UAC_FORMAT_TYPE desc\n",
+				iface_no, altno);
+			continue;
+		}
+		if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8)) ||
+		    ((protocol == UAC_VERSION_2) && (fmt->bLength < 6))) {
+			dev_err(&dev->dev,
+				"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
+				iface_no, altno);
+			continue;
+		}
+
+		/*
+		 * Blue Microphones workaround: The last altsetting is identical
+		 * with the previous one, except for a larger packet size, but
+		 * is actually a mislabeled two-channel setting; ignore it.
+		 */
+		if (fmt->bNrChannels == 1 &&
+		    fmt->bSubframeSize == 2 &&
+		    altno == 2 && num == 3 &&
+		    fp && fp->altsetting == 1 && fp->channels == 1 &&
+		    fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
+		    protocol == UAC_VERSION_1 &&
+		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
+							fp->maxpacksize * 2)
+			continue;
+
+		fp = kzalloc(sizeof(*fp), GFP_KERNEL);
+		if (! fp) {
+			dev_err(&dev->dev, "cannot malloc\n");
+			return -ENOMEM;
+		}
+
+		fp->iface = iface_no;
+		fp->altsetting = altno;
+		fp->altset_idx = i;
+		fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
+		fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
+		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+		fp->protocol = protocol;
+		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+		fp->channels = num_channels;
+		if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
+			fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
+					* (fp->maxpacksize & 0x7ff);
+		fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
+		fp->clock = clock;
+
+		/* some quirks for attributes here */
+
+		switch (chip->usb_id) {
+		case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
+			/* Optoplay sets the sample rate attribute although
+			 * it seems not supporting it in fact.
+			 */
+			fp->attributes &= ~UAC_EP_CS_ATTR_SAMPLE_RATE;
+			break;
+		case USB_ID(0x041e, 0x3020): /* Creative SB Audigy 2 NX */
+		case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
+			/* doesn't set the sample rate attribute, but supports it */
+			fp->attributes |= UAC_EP_CS_ATTR_SAMPLE_RATE;
+			break;
+		case USB_ID(0x0763, 0x2001):  /* M-Audio Quattro USB */
+		case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
+		case USB_ID(0x047f, 0x0ca1): /* plantronics headset */
+		case USB_ID(0x077d, 0x07af): /* Griffin iMic (note that there is
+						an older model 77d:223) */
+		/*
+		 * plantronics headset and Griffin iMic have set adaptive-in
+		 * although it's really not...
+		 */
+			fp->ep_attr &= ~USB_ENDPOINT_SYNCTYPE;
+			if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+				fp->ep_attr |= USB_ENDPOINT_SYNC_ADAPTIVE;
+			else
+				fp->ep_attr |= USB_ENDPOINT_SYNC_SYNC;
+			break;
+		}
+
+		/* ok, let's parse further... */
+		if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream) < 0) {
+			kfree(fp->rate_table);
+			kfree(fp);
+			fp = NULL;
+			continue;
+		}
+
+		/* Create chmap */
+		if (fp->channels != num_channels)
+			chconfig = 0;
+		fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
+
+		dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
+		err = snd_usb_add_audio_stream(chip, stream, fp);
+		if (err < 0) {
+			kfree(fp->rate_table);
+			kfree(fp->chmap);
+			kfree(fp);
+			return err;
+		}
+		/* try to set the interface... */
+		usb_set_interface(chip->dev, iface_no, altno);
+		snd_usb_init_pitch(chip, iface_no, alts, fp);
+		snd_usb_init_sample_rate(chip, iface_no, alts, fp, fp->rate_max);
+	}
+	return 0;
+}
+