Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 1287 insertions, 0 deletions

diff --git a/kernel/sound/usb/quirks.c b/kernel/sound/usb/quirks.c
new file mode 100644
index 000000000..754e68959
--- /dev/null
+++ b/kernel/sound/usb/quirks.c
@@ -0,0 +1,1287 @@
+/*
+ *   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/midi.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "mixer.h"
+#include "mixer_quirks.h"
+#include "midi.h"
+#include "quirks.h"
+#include "helper.h"
+#include "endpoint.h"
+#include "pcm.h"
+#include "clock.h"
+#include "stream.h"
+
+/*
+ * handle the quirks for the contained interfaces
+ */
+static int create_composite_quirk(struct snd_usb_audio *chip,
+				  struct usb_interface *iface,
+				  struct usb_driver *driver,
+				  const struct snd_usb_audio_quirk *quirk_comp)
+{
+	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
+	const struct snd_usb_audio_quirk *quirk;
+	int err;
+
+	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
+		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
+		if (!iface)
+			continue;
+		if (quirk->ifnum != probed_ifnum &&
+		    usb_interface_claimed(iface))
+			continue;
+		err = snd_usb_create_quirk(chip, iface, driver, quirk);
+		if (err < 0)
+			return err;
+	}
+
+	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
+		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
+		if (!iface)
+			continue;
+		if (quirk->ifnum != probed_ifnum &&
+		    !usb_interface_claimed(iface))
+			usb_driver_claim_interface(driver, iface, (void *)-1L);
+	}
+
+	return 0;
+}
+
+static int ignore_interface_quirk(struct snd_usb_audio *chip,
+				  struct usb_interface *iface,
+				  struct usb_driver *driver,
+				  const struct snd_usb_audio_quirk *quirk)
+{
+	return 0;
+}
+
+
+/*
+ * Allow alignment on audio sub-slot (channel samples) rather than
+ * on audio slots (audio frames)
+ */
+static int create_align_transfer_quirk(struct snd_usb_audio *chip,
+				       struct usb_interface *iface,
+				       struct usb_driver *driver,
+				       const struct snd_usb_audio_quirk *quirk)
+{
+	chip->txfr_quirk = 1;
+	return 1;	/* Continue with creating streams and mixer */
+}
+
+static int create_any_midi_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *intf,
+				 struct usb_driver *driver,
+				 const struct snd_usb_audio_quirk *quirk)
+{
+	return snd_usbmidi_create(chip->card, intf, &chip->midi_list, quirk);
+}
+
+/*
+ * create a stream for an interface with proper descriptors
+ */
+static int create_standard_audio_quirk(struct snd_usb_audio *chip,
+				       struct usb_interface *iface,
+				       struct usb_driver *driver,
+				       const struct snd_usb_audio_quirk *quirk)
+{
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	int err;
+
+	alts = &iface->altsetting[0];
+	altsd = get_iface_desc(alts);
+	err = snd_usb_parse_audio_interface(chip, altsd->bInterfaceNumber);
+	if (err < 0) {
+		usb_audio_err(chip, "cannot setup if %d: error %d\n",
+			   altsd->bInterfaceNumber, err);
+		return err;
+	}
+	/* reset the current interface */
+	usb_set_interface(chip->dev, altsd->bInterfaceNumber, 0);
+	return 0;
+}
+
+/*
+ * create a stream for an endpoint/altsetting without proper descriptors
+ */
+static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
+				     struct usb_interface *iface,
+				     struct usb_driver *driver,
+				     const struct snd_usb_audio_quirk *quirk)
+{
+	struct audioformat *fp;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	int stream, err;
+	unsigned *rate_table = NULL;
+
+	fp = kmemdup(quirk->data, sizeof(*fp), GFP_KERNEL);
+	if (!fp) {
+		usb_audio_err(chip, "cannot memdup\n");
+		return -ENOMEM;
+	}
+	if (fp->nr_rates > MAX_NR_RATES) {
+		kfree(fp);
+		return -EINVAL;
+	}
+	if (fp->nr_rates > 0) {
+		rate_table = kmemdup(fp->rate_table,
+				     sizeof(int) * fp->nr_rates, GFP_KERNEL);
+		if (!rate_table) {
+			kfree(fp);
+			return -ENOMEM;
+		}
+		fp->rate_table = rate_table;
+	}
+
+	stream = (fp->endpoint & USB_DIR_IN)
+		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
+	err = snd_usb_add_audio_stream(chip, stream, fp);
+	if (err < 0) {
+		kfree(fp);
+		kfree(rate_table);
+		return err;
+	}
+	if (fp->iface != get_iface_desc(&iface->altsetting[0])->bInterfaceNumber ||
+	    fp->altset_idx >= iface->num_altsetting) {
+		kfree(fp);
+		kfree(rate_table);
+		return -EINVAL;
+	}
+	alts = &iface->altsetting[fp->altset_idx];
+	altsd = get_iface_desc(alts);
+	fp->protocol = altsd->bInterfaceProtocol;
+
+	if (fp->datainterval == 0)
+		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+	if (fp->maxpacksize == 0)
+		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+	usb_set_interface(chip->dev, fp->iface, 0);
+	snd_usb_init_pitch(chip, fp->iface, alts, fp);
+	snd_usb_init_sample_rate(chip, fp->iface, alts, fp, fp->rate_max);
+	return 0;
+}
+
+static int create_auto_pcm_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *iface,
+				 struct usb_driver *driver)
+{
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_endpoint_descriptor *epd;
+	struct uac1_as_header_descriptor *ashd;
+	struct uac_format_type_i_discrete_descriptor *fmtd;
+
+	/*
+	 * Most Roland/Yamaha audio streaming interfaces have more or less
+	 * standard descriptors, but older devices might lack descriptors, and
+	 * future ones might change, so ensure that we fail silently if the
+	 * interface doesn't look exactly right.
+	 */
+
+	/* must have a non-zero altsetting for streaming */
+	if (iface->num_altsetting < 2)
+		return -ENODEV;
+	alts = &iface->altsetting[1];
+	altsd = get_iface_desc(alts);
+
+	/* must have an isochronous endpoint for streaming */
+	if (altsd->bNumEndpoints < 1)
+		return -ENODEV;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_xfer_isoc(epd))
+		return -ENODEV;
+
+	/* must have format descriptors */
+	ashd = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+				       UAC_AS_GENERAL);
+	fmtd = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+				       UAC_FORMAT_TYPE);
+	if (!ashd || ashd->bLength < 7 ||
+	    !fmtd || fmtd->bLength < 8)
+		return -ENODEV;
+
+	return create_standard_audio_quirk(chip, iface, driver, NULL);
+}
+
+static int create_yamaha_midi_quirk(struct snd_usb_audio *chip,
+				    struct usb_interface *iface,
+				    struct usb_driver *driver,
+				    struct usb_host_interface *alts)
+{
+	static const struct snd_usb_audio_quirk yamaha_midi_quirk = {
+		.type = QUIRK_MIDI_YAMAHA
+	};
+	struct usb_midi_in_jack_descriptor *injd;
+	struct usb_midi_out_jack_descriptor *outjd;
+
+	/* must have some valid jack descriptors */
+	injd = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+				       NULL, USB_MS_MIDI_IN_JACK);
+	outjd = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+					NULL, USB_MS_MIDI_OUT_JACK);
+	if (!injd && !outjd)
+		return -ENODEV;
+	if (injd && (injd->bLength < 5 ||
+		     (injd->bJackType != USB_MS_EMBEDDED &&
+		      injd->bJackType != USB_MS_EXTERNAL)))
+		return -ENODEV;
+	if (outjd && (outjd->bLength < 6 ||
+		      (outjd->bJackType != USB_MS_EMBEDDED &&
+		       outjd->bJackType != USB_MS_EXTERNAL)))
+		return -ENODEV;
+	return create_any_midi_quirk(chip, iface, driver, &yamaha_midi_quirk);
+}
+
+static int create_roland_midi_quirk(struct snd_usb_audio *chip,
+				    struct usb_interface *iface,
+				    struct usb_driver *driver,
+				    struct usb_host_interface *alts)
+{
+	static const struct snd_usb_audio_quirk roland_midi_quirk = {
+		.type = QUIRK_MIDI_ROLAND
+	};
+	u8 *roland_desc = NULL;
+
+	/* might have a vendor-specific descriptor <06 24 F1 02 ...> */
+	for (;;) {
+		roland_desc = snd_usb_find_csint_desc(alts->extra,
+						      alts->extralen,
+						      roland_desc, 0xf1);
+		if (!roland_desc)
+			return -ENODEV;
+		if (roland_desc[0] < 6 || roland_desc[3] != 2)
+			continue;
+		return create_any_midi_quirk(chip, iface, driver,
+					     &roland_midi_quirk);
+	}
+}
+
+static int create_std_midi_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *iface,
+				 struct usb_driver *driver,
+				 struct usb_host_interface *alts)
+{
+	struct usb_ms_header_descriptor *mshd;
+	struct usb_ms_endpoint_descriptor *msepd;
+
+	/* must have the MIDIStreaming interface header descriptor*/
+	mshd = (struct usb_ms_header_descriptor *)alts->extra;
+	if (alts->extralen < 7 ||
+	    mshd->bLength < 7 ||
+	    mshd->bDescriptorType != USB_DT_CS_INTERFACE ||
+	    mshd->bDescriptorSubtype != USB_MS_HEADER)
+		return -ENODEV;
+	/* must have the MIDIStreaming endpoint descriptor*/
+	msepd = (struct usb_ms_endpoint_descriptor *)alts->endpoint[0].extra;
+	if (alts->endpoint[0].extralen < 4 ||
+	    msepd->bLength < 4 ||
+	    msepd->bDescriptorType != USB_DT_CS_ENDPOINT ||
+	    msepd->bDescriptorSubtype != UAC_MS_GENERAL ||
+	    msepd->bNumEmbMIDIJack < 1 ||
+	    msepd->bNumEmbMIDIJack > 16)
+		return -ENODEV;
+
+	return create_any_midi_quirk(chip, iface, driver, NULL);
+}
+
+static int create_auto_midi_quirk(struct snd_usb_audio *chip,
+				  struct usb_interface *iface,
+				  struct usb_driver *driver)
+{
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_endpoint_descriptor *epd;
+	int err;
+
+	alts = &iface->altsetting[0];
+	altsd = get_iface_desc(alts);
+
+	/* must have at least one bulk/interrupt endpoint for streaming */
+	if (altsd->bNumEndpoints < 1)
+		return -ENODEV;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_xfer_bulk(epd) &&
+	    !usb_endpoint_xfer_int(epd))
+		return -ENODEV;
+
+	switch (USB_ID_VENDOR(chip->usb_id)) {
+	case 0x0499: /* Yamaha */
+		err = create_yamaha_midi_quirk(chip, iface, driver, alts);
+		if (err != -ENODEV)
+			return err;
+		break;
+	case 0x0582: /* Roland */
+		err = create_roland_midi_quirk(chip, iface, driver, alts);
+		if (err != -ENODEV)
+			return err;
+		break;
+	}
+
+	return create_std_midi_quirk(chip, iface, driver, alts);
+}
+
+static int create_autodetect_quirk(struct snd_usb_audio *chip,
+				   struct usb_interface *iface,
+				   struct usb_driver *driver)
+{
+	int err;
+
+	err = create_auto_pcm_quirk(chip, iface, driver);
+	if (err == -ENODEV)
+		err = create_auto_midi_quirk(chip, iface, driver);
+	return err;
+}
+
+static int create_autodetect_quirks(struct snd_usb_audio *chip,
+				    struct usb_interface *iface,
+				    struct usb_driver *driver,
+				    const struct snd_usb_audio_quirk *quirk)
+{
+	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
+	int ifcount, ifnum, err;
+
+	err = create_autodetect_quirk(chip, iface, driver);
+	if (err < 0)
+		return err;
+
+	/*
+	 * ALSA PCM playback/capture devices cannot be registered in two steps,
+	 * so we have to claim the other corresponding interface here.
+	 */
+	ifcount = chip->dev->actconfig->desc.bNumInterfaces;
+	for (ifnum = 0; ifnum < ifcount; ifnum++) {
+		if (ifnum == probed_ifnum || quirk->ifnum >= 0)
+			continue;
+		iface = usb_ifnum_to_if(chip->dev, ifnum);
+		if (!iface ||
+		    usb_interface_claimed(iface) ||
+		    get_iface_desc(iface->altsetting)->bInterfaceClass !=
+							USB_CLASS_VENDOR_SPEC)
+			continue;
+
+		err = create_autodetect_quirk(chip, iface, driver);
+		if (err >= 0)
+			usb_driver_claim_interface(driver, iface, (void *)-1L);
+	}
+
+	return 0;
+}
+
+/*
+ * Create a stream for an Edirol UA-700/UA-25/UA-4FX interface.  
+ * The only way to detect the sample rate is by looking at wMaxPacketSize.
+ */
+static int create_uaxx_quirk(struct snd_usb_audio *chip,
+			     struct usb_interface *iface,
+			     struct usb_driver *driver,
+			     const struct snd_usb_audio_quirk *quirk)
+{
+	static const struct audioformat ua_format = {
+		.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+		.channels = 2,
+		.fmt_type = UAC_FORMAT_TYPE_I,
+		.altsetting = 1,
+		.altset_idx = 1,
+		.rates = SNDRV_PCM_RATE_CONTINUOUS,
+	};
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct audioformat *fp;
+	int stream, err;
+
+	/* both PCM and MIDI interfaces have 2 or more altsettings */
+	if (iface->num_altsetting < 2)
+		return -ENXIO;
+	alts = &iface->altsetting[1];
+	altsd = get_iface_desc(alts);
+
+	if (altsd->bNumEndpoints == 2) {
+		static const struct snd_usb_midi_endpoint_info ua700_ep = {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0003
+		};
+		static const struct snd_usb_audio_quirk ua700_quirk = {
+			.type = QUIRK_MIDI_FIXED_ENDPOINT,
+			.data = &ua700_ep
+		};
+		static const struct snd_usb_midi_endpoint_info uaxx_ep = {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		};
+		static const struct snd_usb_audio_quirk uaxx_quirk = {
+			.type = QUIRK_MIDI_FIXED_ENDPOINT,
+			.data = &uaxx_ep
+		};
+		const struct snd_usb_audio_quirk *quirk =
+			chip->usb_id == USB_ID(0x0582, 0x002b)
+			? &ua700_quirk : &uaxx_quirk;
+		return snd_usbmidi_create(chip->card, iface,
+					  &chip->midi_list, quirk);
+	}
+
+	if (altsd->bNumEndpoints != 1)
+		return -ENXIO;
+
+	fp = kmemdup(&ua_format, sizeof(*fp), GFP_KERNEL);
+	if (!fp)
+		return -ENOMEM;
+
+	fp->iface = altsd->bInterfaceNumber;
+	fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
+	fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
+	fp->datainterval = 0;
+	fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+
+	switch (fp->maxpacksize) {
+	case 0x120:
+		fp->rate_max = fp->rate_min = 44100;
+		break;
+	case 0x138:
+	case 0x140:
+		fp->rate_max = fp->rate_min = 48000;
+		break;
+	case 0x258:
+	case 0x260:
+		fp->rate_max = fp->rate_min = 96000;
+		break;
+	default:
+		usb_audio_err(chip, "unknown sample rate\n");
+		kfree(fp);
+		return -ENXIO;
+	}
+
+	stream = (fp->endpoint & USB_DIR_IN)
+		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
+	err = snd_usb_add_audio_stream(chip, stream, fp);
+	if (err < 0) {
+		kfree(fp);
+		return err;
+	}
+	usb_set_interface(chip->dev, fp->iface, 0);
+	return 0;
+}
+
+/*
+ * Create a standard mixer for the specified interface.
+ */
+static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
+				       struct usb_interface *iface,
+				       struct usb_driver *driver,
+				       const struct snd_usb_audio_quirk *quirk)
+{
+	if (quirk->ifnum < 0)
+		return 0;
+
+	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
+}
+
+/*
+ * audio-interface quirks
+ *
+ * returns zero if no standard audio/MIDI parsing is needed.
+ * returns a positive value if standard audio/midi interfaces are parsed
+ * after this.
+ * returns a negative value at error.
+ */
+int snd_usb_create_quirk(struct snd_usb_audio *chip,
+			 struct usb_interface *iface,
+			 struct usb_driver *driver,
+			 const struct snd_usb_audio_quirk *quirk)
+{
+	typedef int (*quirk_func_t)(struct snd_usb_audio *,
+				    struct usb_interface *,
+				    struct usb_driver *,
+				    const struct snd_usb_audio_quirk *);
+	static const quirk_func_t quirk_funcs[] = {
+		[QUIRK_IGNORE_INTERFACE] = ignore_interface_quirk,
+		[QUIRK_COMPOSITE] = create_composite_quirk,
+		[QUIRK_AUTODETECT] = create_autodetect_quirks,
+		[QUIRK_MIDI_STANDARD_INTERFACE] = create_any_midi_quirk,
+		[QUIRK_MIDI_FIXED_ENDPOINT] = create_any_midi_quirk,
+		[QUIRK_MIDI_YAMAHA] = create_any_midi_quirk,
+		[QUIRK_MIDI_ROLAND] = create_any_midi_quirk,
+		[QUIRK_MIDI_MIDIMAN] = create_any_midi_quirk,
+		[QUIRK_MIDI_NOVATION] = create_any_midi_quirk,
+		[QUIRK_MIDI_RAW_BYTES] = create_any_midi_quirk,
+		[QUIRK_MIDI_EMAGIC] = create_any_midi_quirk,
+		[QUIRK_MIDI_CME] = create_any_midi_quirk,
+		[QUIRK_MIDI_AKAI] = create_any_midi_quirk,
+		[QUIRK_MIDI_FTDI] = create_any_midi_quirk,
+		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
+		[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
+		[QUIRK_AUDIO_EDIROL_UAXX] = create_uaxx_quirk,
+		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
+		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
+	};
+
+	if (quirk->type < QUIRK_TYPE_COUNT) {
+		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
+	} else {
+		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
+		return -ENXIO;
+	}
+}
+
+/*
+ * boot quirks
+ */
+
+#define EXTIGY_FIRMWARE_SIZE_OLD 794
+#define EXTIGY_FIRMWARE_SIZE_NEW 483
+
+static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
+{
+	struct usb_host_config *config = dev->actconfig;
+	int err;
+
+	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||
+	    le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_NEW) {
+		dev_dbg(&dev->dev, "sending Extigy boot sequence...\n");
+		/* Send message to force it to reconnect with full interface. */
+		err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev,0),
+				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
+		if (err < 0)
+			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
+		err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
+				&dev->descriptor, sizeof(dev->descriptor));
+		config = dev->actconfig;
+		if (err < 0)
+			dev_dbg(&dev->dev, "error usb_get_descriptor: %d\n", err);
+		err = usb_reset_configuration(dev);
+		if (err < 0)
+			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
+		dev_dbg(&dev->dev, "extigy_boot: new boot length = %d\n",
+			    le16_to_cpu(get_cfg_desc(config)->wTotalLength));
+		return -ENODEV; /* quit this anyway */
+	}
+	return 0;
+}
+
+static int snd_usb_audigy2nx_boot_quirk(struct usb_device *dev)
+{
+	u8 buf = 1;
+
+	snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), 0x2a,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			0, 0, &buf, 1);
+	if (buf == 0) {
+		snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0x29,
+				USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+				1, 2000, NULL, 0);
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static int snd_usb_fasttrackpro_boot_quirk(struct usb_device *dev)
+{
+	int err;
+
+	if (dev->actconfig->desc.bConfigurationValue == 1) {
+		dev_info(&dev->dev,
+			   "Fast Track Pro switching to config #2\n");
+		/* This function has to be available by the usb core module.
+		 * if it is not avialable the boot quirk has to be left out
+		 * and the configuration has to be set by udev or hotplug
+		 * rules
+		 */
+		err = usb_driver_set_configuration(dev, 2);
+		if (err < 0)
+			dev_dbg(&dev->dev,
+				"error usb_driver_set_configuration: %d\n",
+				err);
+		/* Always return an error, so that we stop creating a device
+		   that will just be destroyed and recreated with a new
+		   configuration */
+		return -ENODEV;
+	} else
+		dev_info(&dev->dev, "Fast Track Pro config OK\n");
+
+	return 0;
+}
+
+/*
+ * C-Media CM106/CM106+ have four 16-bit internal registers that are nicely
+ * documented in the device's data sheet.
+ */
+static int snd_usb_cm106_write_int_reg(struct usb_device *dev, int reg, u16 value)
+{
+	u8 buf[4];
+	buf[0] = 0x20;
+	buf[1] = value & 0xff;
+	buf[2] = (value >> 8) & 0xff;
+	buf[3] = reg;
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_SET_CONFIGURATION,
+			       USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
+			       0, 0, &buf, 4);
+}
+
+static int snd_usb_cm106_boot_quirk(struct usb_device *dev)
+{
+	/*
+	 * Enable line-out driver mode, set headphone source to front
+	 * channels, enable stereo mic.
+	 */
+	return snd_usb_cm106_write_int_reg(dev, 2, 0x8004);
+}
+
+/*
+ * C-Media CM6206 is based on CM106 with two additional
+ * registers that are not documented in the data sheet.
+ * Values here are chosen based on sniffing USB traffic
+ * under Windows.
+ */
+static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
+{
+	int err  = 0, reg;
+	int val[] = {0x2004, 0x3000, 0xf800, 0x143f, 0x0000, 0x3000};
+
+	for (reg = 0; reg < ARRAY_SIZE(val); reg++) {
+		err = snd_usb_cm106_write_int_reg(dev, reg, val[reg]);
+		if (err < 0)
+			return err;
+	}
+
+	return err;
+}
+
+/* quirk for Plantronics GameCom 780 with CM6302 chip */
+static int snd_usb_gamecon780_boot_quirk(struct usb_device *dev)
+{
+	/* set the initial volume and don't change; other values are either
+	 * too loud or silent due to firmware bug (bko#65251)
+	 */
+	u8 buf[2] = { 0x74, 0xe3 };
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			UAC_FU_VOLUME << 8, 9 << 8, buf, 2);
+}
+
+/*
+ * Novation Twitch DJ controller
+ * Focusrite Novation Saffire 6 USB audio card
+ */
+static int snd_usb_novation_boot_quirk(struct usb_device *dev)
+{
+	/* preemptively set up the device because otherwise the
+	 * raw MIDI endpoints are not active */
+	usb_set_interface(dev, 0, 1);
+	return 0;
+}
+
+/*
+ * This call will put the synth in "USB send" mode, i.e it will send MIDI
+ * messages through USB (this is disabled at startup). The synth will
+ * acknowledge by sending a sysex on endpoint 0x85 and by displaying a USB
+ * sign on its LCD. Values here are chosen based on sniffing USB traffic
+ * under Windows.
+ */
+static int snd_usb_accessmusic_boot_quirk(struct usb_device *dev)
+{
+	int err, actual_length;
+
+	/* "midi send" enable */
+	static const u8 seq[] = { 0x4e, 0x73, 0x52, 0x01 };
+
+	void *buf = kmemdup(seq, ARRAY_SIZE(seq), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x05), buf,
+			ARRAY_SIZE(seq), &actual_length, 1000);
+	kfree(buf);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * Some sound cards from Native Instruments are in fact compliant to the USB
+ * audio standard of version 2 and other approved USB standards, even though
+ * they come up as vendor-specific device when first connected.
+ *
+ * However, they can be told to come up with a new set of descriptors
+ * upon their next enumeration, and the interfaces announced by the new
+ * descriptors will then be handled by the kernel's class drivers. As the
+ * product ID will also change, no further checks are required.
+ */
+
+static int snd_usb_nativeinstruments_boot_quirk(struct usb_device *dev)
+{
+	int ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+				  0xaf, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+				  1, 0, NULL, 0, 1000);
+
+	if (ret < 0)
+		return ret;
+
+	usb_reset_device(dev);
+
+	/* return -EAGAIN, so the creation of an audio interface for this
+	 * temporary device is aborted. The device will reconnect with a
+	 * new product ID */
+	return -EAGAIN;
+}
+
+static void mbox2_setup_48_24_magic(struct usb_device *dev)
+{
+	u8 srate[3];
+	u8 temp[12];
+
+	/* Choose 48000Hz permanently */
+	srate[0] = 0x80;
+	srate[1] = 0xbb;
+	srate[2] = 0x00;
+
+	/* Send the magic! */
+	snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+		0x01, 0x22, 0x0100, 0x0085, &temp, 0x0003);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x81, 0xa2, 0x0100, 0x0085, &srate, 0x0003);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x81, 0xa2, 0x0100, 0x0086, &srate, 0x0003);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x81, 0xa2, 0x0100, 0x0003, &srate, 0x0003);
+	return;
+}
+
+/* Digidesign Mbox 2 needs to load firmware onboard
+ * and driver must wait a few seconds for initialisation.
+ */
+
+#define MBOX2_FIRMWARE_SIZE    646
+#define MBOX2_BOOT_LOADING     0x01 /* Hard coded into the device */
+#define MBOX2_BOOT_READY       0x02 /* Hard coded into the device */
+
+static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
+{
+	struct usb_host_config *config = dev->actconfig;
+	int err;
+	u8 bootresponse[0x12];
+	int fwsize;
+	int count;
+
+	fwsize = le16_to_cpu(get_cfg_desc(config)->wTotalLength);
+
+	if (fwsize != MBOX2_FIRMWARE_SIZE) {
+		dev_err(&dev->dev, "Invalid firmware size=%d.\n", fwsize);
+		return -ENODEV;
+	}
+
+	dev_dbg(&dev->dev, "Sending Digidesign Mbox 2 boot sequence...\n");
+
+	count = 0;
+	bootresponse[0] = MBOX2_BOOT_LOADING;
+	while ((bootresponse[0] == MBOX2_BOOT_LOADING) && (count < 10)) {
+		msleep(500); /* 0.5 second delay */
+		snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			/* Control magic - load onboard firmware */
+			0x85, 0xc0, 0x0001, 0x0000, &bootresponse, 0x0012);
+		if (bootresponse[0] == MBOX2_BOOT_READY)
+			break;
+		dev_dbg(&dev->dev, "device not ready, resending boot sequence...\n");
+		count++;
+	}
+
+	if (bootresponse[0] != MBOX2_BOOT_READY) {
+		dev_err(&dev->dev, "Unknown bootresponse=%d, or timed out, ignoring device.\n", bootresponse[0]);
+		return -ENODEV;
+	}
+
+	dev_dbg(&dev->dev, "device initialised!\n");
+
+	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
+		&dev->descriptor, sizeof(dev->descriptor));
+	config = dev->actconfig;
+	if (err < 0)
+		dev_dbg(&dev->dev, "error usb_get_descriptor: %d\n", err);
+
+	err = usb_reset_configuration(dev);
+	if (err < 0)
+		dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
+	dev_dbg(&dev->dev, "mbox2_boot: new boot length = %d\n",
+		le16_to_cpu(get_cfg_desc(config)->wTotalLength));
+
+	mbox2_setup_48_24_magic(dev);
+
+	dev_info(&dev->dev, "Digidesign Mbox 2: 24bit 48kHz");
+
+	return 0; /* Successful boot */
+}
+
+/*
+ * Setup quirks
+ */
+#define MAUDIO_SET		0x01 /* parse device_setup */
+#define MAUDIO_SET_COMPATIBLE	0x80 /* use only "win-compatible" interfaces */
+#define MAUDIO_SET_DTS		0x02 /* enable DTS Digital Output */
+#define MAUDIO_SET_96K		0x04 /* 48-96KHz rate if set, 8-48KHz otherwise */
+#define MAUDIO_SET_24B		0x08 /* 24bits sample if set, 16bits otherwise */
+#define MAUDIO_SET_DI		0x10 /* enable Digital Input */
+#define MAUDIO_SET_MASK		0x1f /* bit mask for setup value */
+#define MAUDIO_SET_24B_48K_DI	 0x19 /* 24bits+48KHz+Digital Input */
+#define MAUDIO_SET_24B_48K_NOTDI 0x09 /* 24bits+48KHz+No Digital Input */
+#define MAUDIO_SET_16B_48K_DI	 0x11 /* 16bits+48KHz+Digital Input */
+#define MAUDIO_SET_16B_48K_NOTDI 0x01 /* 16bits+48KHz+No Digital Input */
+
+static int quattro_skip_setting_quirk(struct snd_usb_audio *chip,
+				      int iface, int altno)
+{
+	/* Reset ALL ifaces to 0 altsetting.
+	 * Call it for every possible altsetting of every interface.
+	 */
+	usb_set_interface(chip->dev, iface, 0);
+	if (chip->setup & MAUDIO_SET) {
+		if (chip->setup & MAUDIO_SET_COMPATIBLE) {
+			if (iface != 1 && iface != 2)
+				return 1; /* skip all interfaces but 1 and 2 */
+		} else {
+			unsigned int mask;
+			if (iface == 1 || iface == 2)
+				return 1; /* skip interfaces 1 and 2 */
+			if ((chip->setup & MAUDIO_SET_96K) && altno != 1)
+				return 1; /* skip this altsetting */
+			mask = chip->setup & MAUDIO_SET_MASK;
+			if (mask == MAUDIO_SET_24B_48K_DI && altno != 2)
+				return 1; /* skip this altsetting */
+			if (mask == MAUDIO_SET_24B_48K_NOTDI && altno != 3)
+				return 1; /* skip this altsetting */
+			if (mask == MAUDIO_SET_16B_48K_NOTDI && altno != 4)
+				return 1; /* skip this altsetting */
+		}
+	}
+	usb_audio_dbg(chip,
+		    "using altsetting %d for interface %d config %d\n",
+		    altno, iface, chip->setup);
+	return 0; /* keep this altsetting */
+}
+
+static int audiophile_skip_setting_quirk(struct snd_usb_audio *chip,
+					 int iface,
+					 int altno)
+{
+	/* Reset ALL ifaces to 0 altsetting.
+	 * Call it for every possible altsetting of every interface.
+	 */
+	usb_set_interface(chip->dev, iface, 0);
+
+	if (chip->setup & MAUDIO_SET) {
+		unsigned int mask;
+		if ((chip->setup & MAUDIO_SET_DTS) && altno != 6)
+			return 1; /* skip this altsetting */
+		if ((chip->setup & MAUDIO_SET_96K) && altno != 1)
+			return 1; /* skip this altsetting */
+		mask = chip->setup & MAUDIO_SET_MASK;
+		if (mask == MAUDIO_SET_24B_48K_DI && altno != 2)
+			return 1; /* skip this altsetting */
+		if (mask == MAUDIO_SET_24B_48K_NOTDI && altno != 3)
+			return 1; /* skip this altsetting */
+		if (mask == MAUDIO_SET_16B_48K_DI && altno != 4)
+			return 1; /* skip this altsetting */
+		if (mask == MAUDIO_SET_16B_48K_NOTDI && altno != 5)
+			return 1; /* skip this altsetting */
+	}
+
+	return 0; /* keep this altsetting */
+}
+
+static int fasttrackpro_skip_setting_quirk(struct snd_usb_audio *chip,
+					   int iface, int altno)
+{
+	/* Reset ALL ifaces to 0 altsetting.
+	 * Call it for every possible altsetting of every interface.
+	 */
+	usb_set_interface(chip->dev, iface, 0);
+
+	/* possible configuration where both inputs and only one output is
+	 *used is not supported by the current setup
+	 */
+	if (chip->setup & (MAUDIO_SET | MAUDIO_SET_24B)) {
+		if (chip->setup & MAUDIO_SET_96K) {
+			if (altno != 3 && altno != 6)
+				return 1;
+		} else if (chip->setup & MAUDIO_SET_DI) {
+			if (iface == 4)
+				return 1; /* no analog input */
+			if (altno != 2 && altno != 5)
+				return 1; /* enable only altsets 2 and 5 */
+		} else {
+			if (iface == 5)
+				return 1; /* disable digialt input */
+			if (altno != 2 && altno != 5)
+				return 1; /* enalbe only altsets 2 and 5 */
+		}
+	} else {
+		/* keep only 16-Bit mode */
+		if (altno != 1)
+			return 1;
+	}
+
+	usb_audio_dbg(chip,
+		    "using altsetting %d for interface %d config %d\n",
+		    altno, iface, chip->setup);
+	return 0; /* keep this altsetting */
+}
+
+int snd_usb_apply_interface_quirk(struct snd_usb_audio *chip,
+				  int iface,
+				  int altno)
+{
+	/* audiophile usb: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x0763, 0x2003))
+		return audiophile_skip_setting_quirk(chip, iface, altno);
+	/* quattro usb: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x0763, 0x2001))
+		return quattro_skip_setting_quirk(chip, iface, altno);
+	/* fasttrackpro usb: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x0763, 0x2012))
+		return fasttrackpro_skip_setting_quirk(chip, iface, altno);
+
+	return 0;
+}
+
+int snd_usb_apply_boot_quirk(struct usb_device *dev,
+			     struct usb_interface *intf,
+			     const struct snd_usb_audio_quirk *quirk)
+{
+	u32 id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
+			le16_to_cpu(dev->descriptor.idProduct));
+
+	switch (id) {
+	case USB_ID(0x041e, 0x3000):
+		/* SB Extigy needs special boot-up sequence */
+		/* if more models come, this will go to the quirk list. */
+		return snd_usb_extigy_boot_quirk(dev, intf);
+
+	case USB_ID(0x041e, 0x3020):
+		/* SB Audigy 2 NX needs its own boot-up magic, too */
+		return snd_usb_audigy2nx_boot_quirk(dev);
+
+	case USB_ID(0x10f5, 0x0200):
+		/* C-Media CM106 / Turtle Beach Audio Advantage Roadie */
+		return snd_usb_cm106_boot_quirk(dev);
+
+	case USB_ID(0x0d8c, 0x0102):
+		/* C-Media CM6206 / CM106-Like Sound Device */
+	case USB_ID(0x0ccd, 0x00b1): /* Terratec Aureon 7.1 USB */
+		return snd_usb_cm6206_boot_quirk(dev);
+
+	case USB_ID(0x0dba, 0x3000):
+		/* Digidesign Mbox 2 */
+		return snd_usb_mbox2_boot_quirk(dev);
+
+	case USB_ID(0x1235, 0x0010): /* Focusrite Novation Saffire 6 USB */
+	case USB_ID(0x1235, 0x0018): /* Focusrite Novation Twitch */
+		return snd_usb_novation_boot_quirk(dev);
+
+	case USB_ID(0x133e, 0x0815):
+		/* Access Music VirusTI Desktop */
+		return snd_usb_accessmusic_boot_quirk(dev);
+
+	case USB_ID(0x17cc, 0x1000): /* Komplete Audio 6 */
+	case USB_ID(0x17cc, 0x1010): /* Traktor Audio 6 */
+	case USB_ID(0x17cc, 0x1020): /* Traktor Audio 10 */
+		return snd_usb_nativeinstruments_boot_quirk(dev);
+	case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
+		return snd_usb_fasttrackpro_boot_quirk(dev);
+	case USB_ID(0x047f, 0xc010): /* Plantronics Gamecom 780 */
+		return snd_usb_gamecon780_boot_quirk(dev);
+	}
+
+	return 0;
+}
+
+/*
+ * check if the device uses big-endian samples
+ */
+int snd_usb_is_big_endian_format(struct snd_usb_audio *chip, struct audioformat *fp)
+{
+	/* it depends on altsetting whether the device is big-endian or not */
+	switch (chip->usb_id) {
+	case USB_ID(0x0763, 0x2001): /* M-Audio Quattro: captured data only */
+		if (fp->altsetting == 2 || fp->altsetting == 3 ||
+			fp->altsetting == 5 || fp->altsetting == 6)
+			return 1;
+		break;
+	case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
+		if (chip->setup == 0x00 ||
+			fp->altsetting == 1 || fp->altsetting == 2 ||
+			fp->altsetting == 3)
+			return 1;
+		break;
+	case USB_ID(0x0763, 0x2012): /* M-Audio Fast Track Pro */
+		if (fp->altsetting == 2 || fp->altsetting == 3 ||
+			fp->altsetting == 5 || fp->altsetting == 6)
+			return 1;
+		break;
+	}
+	return 0;
+}
+
+/*
+ * For E-Mu 0404USB/0202USB/TrackerPre/0204 sample rate should be set for device,
+ * not for interface.
+ */
+
+enum {
+	EMU_QUIRK_SR_44100HZ = 0,
+	EMU_QUIRK_SR_48000HZ,
+	EMU_QUIRK_SR_88200HZ,
+	EMU_QUIRK_SR_96000HZ,
+	EMU_QUIRK_SR_176400HZ,
+	EMU_QUIRK_SR_192000HZ
+};
+
+static void set_format_emu_quirk(struct snd_usb_substream *subs,
+				 struct audioformat *fmt)
+{
+	unsigned char emu_samplerate_id = 0;
+
+	/* When capture is active
+	 * sample rate shouldn't be changed
+	 * by playback substream
+	 */
+	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (subs->stream->substream[SNDRV_PCM_STREAM_CAPTURE].interface != -1)
+			return;
+	}
+
+	switch (fmt->rate_min) {
+	case 48000:
+		emu_samplerate_id = EMU_QUIRK_SR_48000HZ;
+		break;
+	case 88200:
+		emu_samplerate_id = EMU_QUIRK_SR_88200HZ;
+		break;
+	case 96000:
+		emu_samplerate_id = EMU_QUIRK_SR_96000HZ;
+		break;
+	case 176400:
+		emu_samplerate_id = EMU_QUIRK_SR_176400HZ;
+		break;
+	case 192000:
+		emu_samplerate_id = EMU_QUIRK_SR_192000HZ;
+		break;
+	default:
+		emu_samplerate_id = EMU_QUIRK_SR_44100HZ;
+		break;
+	}
+	snd_emuusb_set_samplerate(subs->stream->chip, emu_samplerate_id);
+	subs->pkt_offset_adj = (emu_samplerate_id >= EMU_QUIRK_SR_176400HZ) ? 4 : 0;
+}
+
+void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
+			      struct audioformat *fmt)
+{
+	switch (subs->stream->chip->usb_id) {
+	case USB_ID(0x041e, 0x3f02): /* E-Mu 0202 USB */
+	case USB_ID(0x041e, 0x3f04): /* E-Mu 0404 USB */
+	case USB_ID(0x041e, 0x3f0a): /* E-Mu Tracker Pre */
+	case USB_ID(0x041e, 0x3f19): /* E-Mu 0204 USB */
+		set_format_emu_quirk(subs, fmt);
+		break;
+	}
+}
+
+bool snd_usb_get_sample_rate_quirk(struct snd_usb_audio *chip)
+{
+	/* devices which do not support reading the sample rate. */
+	switch (chip->usb_id) {
+	case USB_ID(0x045E, 0x075D): /* MS Lifecam Cinema  */
+	case USB_ID(0x045E, 0x076D): /* MS Lifecam HD-5000 */
+	case USB_ID(0x045E, 0x0772): /* MS Lifecam Studio */
+	case USB_ID(0x045E, 0x0779): /* MS Lifecam HD-3000 */
+	case USB_ID(0x04D8, 0xFEEA): /* Benchmark DAC1 Pre */
+	case USB_ID(0x074D, 0x3553): /* Outlaw RR2150 (Micronas UAC3553B) */
+		return true;
+	}
+	return false;
+}
+
+/* Marantz/Denon USB DACs need a vendor cmd to switch
+ * between PCM and native DSD mode
+ */
+static bool is_marantz_denon_dac(unsigned int id)
+{
+	switch (id) {
+	case USB_ID(0x154e, 0x1003): /* Denon DA-300USB */
+	case USB_ID(0x154e, 0x3005): /* Marantz HD-DAC1 */
+	case USB_ID(0x154e, 0x3006): /* Marantz SA-14S1 */
+		return true;
+	}
+	return false;
+}
+
+int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
+			      struct audioformat *fmt)
+{
+	struct usb_device *dev = subs->dev;
+	int err;
+
+	if (is_marantz_denon_dac(subs->stream->chip->usb_id)) {
+		/* First switch to alt set 0, otherwise the mode switch cmd
+		 * will not be accepted by the DAC
+		 */
+		err = usb_set_interface(dev, fmt->iface, 0);
+		if (err < 0)
+			return err;
+
+		mdelay(20); /* Delay needed after setting the interface */
+
+		switch (fmt->altsetting) {
+		case 2: /* DSD mode requested */
+		case 1: /* PCM mode requested */
+			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
+					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+					      fmt->altsetting - 1, 1, NULL, 0);
+			if (err < 0)
+				return err;
+			break;
+		}
+		mdelay(20);
+	}
+	return 0;
+}
+
+void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep)
+{
+	/*
+	 * "Playback Design" products send bogus feedback data at the start
+	 * of the stream. Ignore them.
+	 */
+	if ((le16_to_cpu(ep->chip->dev->descriptor.idVendor) == 0x23ba) &&
+	    ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
+		ep->skip_packets = 4;
+
+	/*
+	 * M-Audio Fast Track C400/C600 - when packets are not skipped, real
+	 * world latency varies by approx. +/- 50 frames (at 96KHz) each time
+	 * the stream is (re)started. When skipping packets 16 at endpoint
+	 * start up, the real world latency is stable within +/- 1 frame (also
+	 * across power cycles).
+	 */
+	if ((ep->chip->usb_id == USB_ID(0x0763, 0x2030) ||
+	     ep->chip->usb_id == USB_ID(0x0763, 0x2031)) &&
+	    ep->type == SND_USB_ENDPOINT_TYPE_DATA)
+		ep->skip_packets = 16;
+}
+
+void snd_usb_set_interface_quirk(struct usb_device *dev)
+{
+	/*
+	 * "Playback Design" products need a 50ms delay after setting the
+	 * USB interface.
+	 */
+	if (le16_to_cpu(dev->descriptor.idVendor) == 0x23ba)
+		mdelay(50);
+}
+
+void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
+			   __u8 request, __u8 requesttype, __u16 value,
+			   __u16 index, void *data, __u16 size)
+{
+	/*
+	 * "Playback Design" products need a 20ms delay after each
+	 * class compliant request
+	 */
+	if ((le16_to_cpu(dev->descriptor.idVendor) == 0x23ba) &&
+	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
+		mdelay(20);
+
+	/* Marantz/Denon devices with USB DAC functionality need a delay
+	 * after each class compliant request
+	 */
+	if (is_marantz_denon_dac(USB_ID(le16_to_cpu(dev->descriptor.idVendor),
+					le16_to_cpu(dev->descriptor.idProduct)))
+	    && (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
+		mdelay(20);
+
+	/* Zoom R16/24 needs a tiny delay here, otherwise requests like
+	 * get/set frequency return as failed despite actually succeeding.
+	 */
+	if ((le16_to_cpu(dev->descriptor.idVendor) == 0x1686) &&
+	    (le16_to_cpu(dev->descriptor.idProduct) == 0x00dd) &&
+	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
+		mdelay(1);
+}
+
+/*
+ * snd_usb_interface_dsd_format_quirks() is called from format.c to
+ * augment the PCM format bit-field for DSD types. The UAC standards
+ * don't have a designated bit field to denote DSD-capable interfaces,
+ * hence all hardware that is known to support this format has to be
+ * listed here.
+ */
+u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
+					struct audioformat *fp,
+					unsigned int sample_bytes)
+{
+	/* Playback Designs */
+	if (le16_to_cpu(chip->dev->descriptor.idVendor) == 0x23ba) {
+		switch (fp->altsetting) {
+		case 1:
+			fp->dsd_dop = true;
+			return SNDRV_PCM_FMTBIT_DSD_U16_LE;
+		case 2:
+			fp->dsd_bitrev = true;
+			return SNDRV_PCM_FMTBIT_DSD_U8;
+		case 3:
+			fp->dsd_bitrev = true;
+			return SNDRV_PCM_FMTBIT_DSD_U16_LE;
+		}
+	}
+
+	/* XMOS based USB DACs */
+	switch (chip->usb_id) {
+	case USB_ID(0x20b1, 0x3008): /* iFi Audio micro/nano iDSD */
+	case USB_ID(0x20b1, 0x2008): /* Matrix Audio X-Sabre */
+	case USB_ID(0x20b1, 0x300a): /* Matrix Audio Mini-i Pro */
+		if (fp->altsetting == 2)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+		break;
+
+	case USB_ID(0x20b1, 0x2009): /* DIYINHK DSD DXD 384kHz USB to I2S/DSD */
+	case USB_ID(0x20b1, 0x2023): /* JLsounds I2SoverUSB */
+		if (fp->altsetting == 3)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+		break;
+	default:
+		break;
+	}
+
+	/* Denon/Marantz devices with USB DAC functionality */
+	if (is_marantz_denon_dac(chip->usb_id)) {
+		if (fp->altsetting == 2)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+	}
+
+	return 0;
+}