text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   */
  
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/usb.h>
  #include <linux/usb/audio.h>
  #include <linux/usb/midi.h>
  #include <linux/bits.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;
  
  	if (chip->usb_id == USB_ID(0x1686, 0x00dd)) /* Zoom R16/24 */
  		chip->tx_length_quirk = 1;
  
  	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)
  		return -ENOMEM;
  
  	INIT_LIST_HEAD(&fp->list);
  	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)
  		goto error;
  	if (fp->iface != get_iface_desc(&iface->altsetting[0])->bInterfaceNumber ||
  	    fp->altset_idx >= iface->num_altsetting) {
  		err = -EINVAL;
  		goto error;
  	}
  	alts = &iface->altsetting[fp->altset_idx];
  	altsd = get_iface_desc(alts);
  	if (altsd->bNumEndpoints < 1) {
  		err = -EINVAL;
  		goto error;
  	}
  
  	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;
  
   error:
  	list_del(&fp->list); /* unlink for avoiding double-free */
  	kfree(fp);
  	kfree(rate_table);
  	return err;
  }
  
  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 && !snd_usb_validate_midi_desc(injd)) ||
  	    (outjd && !snd_usb_validate_midi_desc(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,
  					  chip->usb_id);
  	}
  
  	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);
  	INIT_LIST_HEAD(&fp->list);
  
  	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) {
  		list_del(&fp->list); /* unlink for avoiding double-free */
  		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);
  }
  
  
  static int setup_fmt_after_resume_quirk(struct snd_usb_audio *chip,
  				       struct usb_interface *iface,
  				       struct usb_driver *driver,
  				       const struct snd_usb_audio_quirk *quirk)
  {
  	chip->setup_fmt_after_resume_quirk = 1;
  	return 1;	/* Continue with creating streams and mixer */
  }
  
  /*
   * 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_MIDI_CH345] = 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,
  		[QUIRK_SETUP_FMT_AFTER_RESUME] = setup_fmt_after_resume_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);
  }
  
  /*
   * CM6206 registers from the CM6206 datasheet rev 2.1
   */
  #define CM6206_REG0_DMA_MASTER BIT(15)
  #define CM6206_REG0_SPDIFO_RATE_48K (2 << 12)
  #define CM6206_REG0_SPDIFO_RATE_96K (7 << 12)
  /* Bit 4 thru 11 is the S/PDIF category code */
  #define CM6206_REG0_SPDIFO_CAT_CODE_GENERAL (0 << 4)
  #define CM6206_REG0_SPDIFO_EMPHASIS_CD BIT(3)
  #define CM6206_REG0_SPDIFO_COPYRIGHT_NA BIT(2)
  #define CM6206_REG0_SPDIFO_NON_AUDIO BIT(1)
  #define CM6206_REG0_SPDIFO_PRO_FORMAT BIT(0)
  
  #define CM6206_REG1_TEST_SEL_CLK BIT(14)
  #define CM6206_REG1_PLLBIN_EN BIT(13)
  #define CM6206_REG1_SOFT_MUTE_EN BIT(12)
  #define CM6206_REG1_GPIO4_OUT BIT(11)
  #define CM6206_REG1_GPIO4_OE BIT(10)
  #define CM6206_REG1_GPIO3_OUT BIT(9)
  #define CM6206_REG1_GPIO3_OE BIT(8)
  #define CM6206_REG1_GPIO2_OUT BIT(7)
  #define CM6206_REG1_GPIO2_OE BIT(6)
  #define CM6206_REG1_GPIO1_OUT BIT(5)
  #define CM6206_REG1_GPIO1_OE BIT(4)
  #define CM6206_REG1_SPDIFO_INVALID BIT(3)
  #define CM6206_REG1_SPDIF_LOOP_EN BIT(2)
  #define CM6206_REG1_SPDIFO_DIS BIT(1)
  #define CM6206_REG1_SPDIFI_MIX BIT(0)
  
  #define CM6206_REG2_DRIVER_ON BIT(15)
  #define CM6206_REG2_HEADP_SEL_SIDE_CHANNELS (0 << 13)
  #define CM6206_REG2_HEADP_SEL_SURROUND_CHANNELS (1 << 13)
  #define CM6206_REG2_HEADP_SEL_CENTER_SUBW (2 << 13)
  #define CM6206_REG2_HEADP_SEL_FRONT_CHANNELS (3 << 13)
  #define CM6206_REG2_MUTE_HEADPHONE_RIGHT BIT(12)
  #define CM6206_REG2_MUTE_HEADPHONE_LEFT BIT(11)
  #define CM6206_REG2_MUTE_REAR_SURROUND_RIGHT BIT(10)
  #define CM6206_REG2_MUTE_REAR_SURROUND_LEFT BIT(9)
  #define CM6206_REG2_MUTE_SIDE_SURROUND_RIGHT BIT(8)
  #define CM6206_REG2_MUTE_SIDE_SURROUND_LEFT BIT(7)
  #define CM6206_REG2_MUTE_SUBWOOFER BIT(6)
  #define CM6206_REG2_MUTE_CENTER BIT(5)
  #define CM6206_REG2_MUTE_RIGHT_FRONT BIT(3)
  #define CM6206_REG2_MUTE_LEFT_FRONT BIT(3)
  #define CM6206_REG2_EN_BTL BIT(2)
  #define CM6206_REG2_MCUCLKSEL_1_5_MHZ (0)
  #define CM6206_REG2_MCUCLKSEL_3_MHZ (1)
  #define CM6206_REG2_MCUCLKSEL_6_MHZ (2)
  #define CM6206_REG2_MCUCLKSEL_12_MHZ (3)
  
  /* Bit 11..13 sets the sensitivity to FLY tuner volume control VP/VD signal */
  #define CM6206_REG3_FLYSPEED_DEFAULT (2 << 11)
  #define CM6206_REG3_VRAP25EN BIT(10)
  #define CM6206_REG3_MSEL1 BIT(9)
  #define CM6206_REG3_SPDIFI_RATE_44_1K BIT(0 << 7)
  #define CM6206_REG3_SPDIFI_RATE_48K BIT(2 << 7)
  #define CM6206_REG3_SPDIFI_RATE_32K BIT(3 << 7)
  #define CM6206_REG3_PINSEL BIT(6)
  #define CM6206_REG3_FOE BIT(5)
  #define CM6206_REG3_ROE BIT(4)
  #define CM6206_REG3_CBOE BIT(3)
  #define CM6206_REG3_LOSE BIT(2)
  #define CM6206_REG3_HPOE BIT(1)
  #define CM6206_REG3_SPDIFI_CANREC BIT(0)
  
  #define CM6206_REG5_DA_RSTN BIT(13)
  #define CM6206_REG5_AD_RSTN BIT(12)
  #define CM6206_REG5_SPDIFO_AD2SPDO BIT(12)
  #define CM6206_REG5_SPDIFO_SEL_FRONT (0 << 9)
  #define CM6206_REG5_SPDIFO_SEL_SIDE_SUR (1 << 9)
  #define CM6206_REG5_SPDIFO_SEL_CEN_LFE (2 << 9)
  #define CM6206_REG5_SPDIFO_SEL_REAR_SUR (3 << 9)
  #define CM6206_REG5_CODECM BIT(8)
  #define CM6206_REG5_EN_HPF BIT(7)
  #define CM6206_REG5_T_SEL_DSDA4 BIT(6)
  #define CM6206_REG5_T_SEL_DSDA3 BIT(5)
  #define CM6206_REG5_T_SEL_DSDA2 BIT(4)
  #define CM6206_REG5_T_SEL_DSDA1 BIT(3)
  #define CM6206_REG5_T_SEL_DSDAD_NORMAL 0
  #define CM6206_REG5_T_SEL_DSDAD_FRONT 4
  #define CM6206_REG5_T_SEL_DSDAD_S_SURROUND 5
  #define CM6206_REG5_T_SEL_DSDAD_CEN_LFE 6
  #define CM6206_REG5_T_SEL_DSDAD_R_SURROUND 7
  
  static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
  {
  	int err  = 0, reg;
  	int val[] = {
  		/*
  		 * Values here are chosen based on sniffing USB traffic
  		 * under Windows.
  		 *
  		 * REG0: DAC is master, sample rate 48kHz, no copyright
  		 */
  		CM6206_REG0_SPDIFO_RATE_48K |
  		CM6206_REG0_SPDIFO_COPYRIGHT_NA,
  		/*
  		 * REG1: PLL binary search enable, soft mute enable.
  		 */
  		CM6206_REG1_PLLBIN_EN |
  		CM6206_REG1_SOFT_MUTE_EN,
  		/*
  		 * REG2: enable output drivers,
  		 * select front channels to the headphone output,
  		 * then mute the headphone channels, run the MCU
  		 * at 1.5 MHz.
  		 */
  		CM6206_REG2_DRIVER_ON |
  		CM6206_REG2_HEADP_SEL_FRONT_CHANNELS |
  		CM6206_REG2_MUTE_HEADPHONE_RIGHT |
  		CM6206_REG2_MUTE_HEADPHONE_LEFT,
  		/*
  		 * REG3: default flyspeed, set 2.5V mic bias
  		 * enable all line out ports and enable SPDIF
  		 */
  		CM6206_REG3_FLYSPEED_DEFAULT |
  		CM6206_REG3_VRAP25EN |
  		CM6206_REG3_FOE |
  		CM6206_REG3_ROE |
  		CM6206_REG3_CBOE |
  		CM6206_REG3_LOSE |
  		CM6206_REG3_HPOE |
  		CM6206_REG3_SPDIFI_CANREC,
  		/* REG4 is just a bunch of GPIO lines */
  		0x0000,
  		/* REG5: de-assert AD/DA reset signals */
  		CM6206_REG5_DA_RSTN |
  		CM6206_REG5_AD_RSTN };
  
  	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;
  
  	if (snd_usb_pipe_sanity_check(dev, usb_sndintpipe(dev, 0x05)))
  		return -EINVAL;
  	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;
  
  	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
  		return -EINVAL;
  	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 */
  }
  
  static int snd_usb_axefx3_boot_quirk(struct usb_device *dev)
  {
  	int err;
  
  	dev_dbg(&dev->dev, "Waiting for Axe-Fx III to boot up...\n");
  
  	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
  		return -EINVAL;
  	/* If the Axe-Fx III has not fully booted, it will timeout when trying
  	 * to enable the audio streaming interface. A more generous timeout is
  	 * used here to detect when the Axe-Fx III has finished booting as the
  	 * set interface message will be acked once it has
  	 */
  	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
  				USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
  				1, 1, NULL, 0, 120000);
  	if (err < 0) {
  		dev_err(&dev->dev,
  			"failed waiting for Axe-Fx III to boot: %d\n", err);
  		return err;
  	}
  
  	dev_dbg(&dev->dev, "Axe-Fx III is now ready\n");
  
  	err = usb_set_interface(dev, 1, 0);
  	if (err < 0)
  		dev_dbg(&dev->dev,
  			"error stopping Axe-Fx III interface: %d\n", err);
  
  	return 0;
  }
  
  
  #define MICROBOOK_BUF_SIZE 128
  
  static int snd_usb_motu_microbookii_communicate(struct usb_device *dev, u8 *buf,
  						int buf_size, int *length)
  {
  	int err, actual_length;
  
  	if (snd_usb_pipe_sanity_check(dev, usb_sndintpipe(dev, 0x01)))
  		return -EINVAL;
  	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x01), buf, *length,
  				&actual_length, 1000);
  	if (err < 0)
  		return err;
  
  	print_hex_dump(KERN_DEBUG, "MicroBookII snd: ", DUMP_PREFIX_NONE, 16, 1,
  		       buf, actual_length, false);
  
  	memset(buf, 0, buf_size);
  
  	if (snd_usb_pipe_sanity_check(dev, usb_rcvintpipe(dev, 0x82)))
  		return -EINVAL;
  	err = usb_interrupt_msg(dev, usb_rcvintpipe(dev, 0x82), buf, buf_size,
  				&actual_length, 1000);
  	if (err < 0)
  		return err;
  
  	print_hex_dump(KERN_DEBUG, "MicroBookII rcv: ", DUMP_PREFIX_NONE, 16, 1,
  		       buf, actual_length, false);
  
  	*length = actual_length;
  	return 0;
  }
  
  static int snd_usb_motu_microbookii_boot_quirk(struct usb_device *dev)
  {
  	int err, actual_length, poll_attempts = 0;
  	static const u8 set_samplerate_seq[] = { 0x00, 0x00, 0x00, 0x00,
  						 0x00, 0x00, 0x0b, 0x14,
  						 0x00, 0x00, 0x00, 0x01 };
  	static const u8 poll_ready_seq[] = { 0x00, 0x04, 0x00, 0x00,
  					     0x00, 0x00, 0x0b, 0x18 };
  	u8 *buf = kzalloc(MICROBOOK_BUF_SIZE, GFP_KERNEL);
  
  	if (!buf)
  		return -ENOMEM;
  
  	dev_info(&dev->dev, "Waiting for MOTU Microbook II to boot up...\n");
  
  	/* First we tell the device which sample rate to use. */
  	memcpy(buf, set_samplerate_seq, sizeof(set_samplerate_seq));
  	actual_length = sizeof(set_samplerate_seq);
  	err = snd_usb_motu_microbookii_communicate(dev, buf, MICROBOOK_BUF_SIZE,
  						   &actual_length);
  
  	if (err < 0) {
  		dev_err(&dev->dev,
  			"failed setting the sample rate for Motu MicroBook II: %d\n",
  			err);
  		goto free_buf;
  	}
  
  	/* Then we poll every 100 ms until the device informs of its readiness. */
  	while (true) {
  		if (++poll_attempts > 100) {
  			dev_err(&dev->dev,
  				"failed booting Motu MicroBook II: timeout\n");
  			err = -ENODEV;
  			goto free_buf;
  		}
  
  		memset(buf, 0, MICROBOOK_BUF_SIZE);
  		memcpy(buf, poll_ready_seq, sizeof(poll_ready_seq));
  
  		actual_length = sizeof(poll_ready_seq);
  		err = snd_usb_motu_microbookii_communicate(
  			dev, buf, MICROBOOK_BUF_SIZE, &actual_length);
  		if (err < 0) {
  			dev_err(&dev->dev,
  				"failed booting Motu MicroBook II: communication error %d\n",
  				err);
  			goto free_buf;
  		}
  
  		/* the device signals its readiness through a message of the
  		 * form
  		 *           XX 06 00 00 00 00 0b 18  00 00 00 01
  		 * If the device is not yet ready to accept audio data, the
  		 * last byte of that sequence is 00.
  		 */
  		if (actual_length == 12 && buf[actual_length - 1] == 1)
  			break;
  
  		msleep(100);
  	}
  
  	dev_info(&dev->dev, "MOTU MicroBook II ready\n");
  
  free_buf:
  	kfree(buf);
  	return err;
  }
  
  /*
   * 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,
  			     unsigned int id)
  {
  	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);
  	case USB_ID(0x2466, 0x8010): /* Fractal Audio Axe-Fx 3 */
  		return snd_usb_axefx3_boot_quirk(dev);
  	case USB_ID(0x07fd, 0x0004): /* MOTU MicroBook II */
  		return snd_usb_motu_microbookii_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(0x041E, 0x4080): /* Creative Live Cam VF0610 */
  	case USB_ID(0x04D8, 0xFEEA): /* Benchmark DAC1 Pre */
  	case USB_ID(0x0556, 0x0014): /* Phoenix Audio TMX320VC */
  	case USB_ID(0x05A3, 0x9420): /* ELP HD USB Camera */
  	case USB_ID(0x074D, 0x3553): /* Outlaw RR2150 (Micronas UAC3553B) */
  	case USB_ID(0x1395, 0x740a): /* Sennheiser DECT */
  	case USB_ID(0x1901, 0x0191): /* GE B850V3 CP2114 audio interface */
  	case USB_ID(0x21B4, 0x0081): /* AudioQuest DragonFly */
  		return true;
  	}
  
  	/* devices of these vendors don't support reading rate, either */
  	switch (USB_ID_VENDOR(chip->usb_id)) {
  	case 0x045E: /* MS Lifecam */
  	case 0x047F: /* Plantronics */
  	case 0x1de7: /* Phoenix Audio */
  		return true;
  	}
  
  	return false;
  }
  
  /* ITF-USB DSD based DACs need a vendor cmd to switch
   * between PCM and native DSD mode
   */
  static bool is_itf_usb_dsd_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 */
  	case USB_ID(0x1852, 0x5065): /* Luxman DA-06 */
  	case USB_ID(0x0644, 0x8043): /* TEAC UD-501/UD-501V2/UD-503/NT-503 */
  	case USB_ID(0x0644, 0x8044): /* Esoteric D-05X */
  	case USB_ID(0x0644, 0x804a): /* TEAC UD-301 */
  		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_itf_usb_dsd_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;
  
  		msleep(20); /* Delay needed after setting the interface */
  
  		/* Vendor mode switch cmd is required. */
  		if (fmt->formats & SNDRV_PCM_FMTBIT_DSD_U32_BE) {
  			/* DSD mode (DSD_U32) requested */
  			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
  					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
  					      1, 1, NULL, 0);
  			if (err < 0)
  				return err;
  
  		} else {
  			/* PCM or DOP mode (S32) requested */
  			/* PCM mode (S16) requested */
  			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
  					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
  					      0, 1, NULL, 0);
  			if (err < 0)
  				return err;
  
  		}
  		msleep(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 (USB_ID_VENDOR(ep->chip->usb_id) == 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;
  
  	/* Work around devices that report unreasonable feedback data */
  	if ((ep->chip->usb_id == USB_ID(0x0644, 0x8038) ||  /* TEAC UD-H01 */
  	     ep->chip->usb_id == USB_ID(0x1852, 0x5034)) && /* T+A Dac8 */
  	    ep->syncmaxsize == 4)
  		ep->tenor_fb_quirk = 1;
  }
  
  void snd_usb_set_interface_quirk(struct usb_device *dev)
  {
  	struct snd_usb_audio *chip = dev_get_drvdata(&dev->dev);
  
  	if (!chip)
  		return;
  	/*
  	 * "Playback Design" products need a 50ms delay after setting the
  	 * USB interface.
  	 */
  	switch (USB_ID_VENDOR(chip->usb_id)) {
  	case 0x23ba: /* Playback Design */
  	case 0x0644: /* TEAC Corp. */
  		msleep(50);
  		break;
  	}
  }
  
  /* quirk applied after snd_usb_ctl_msg(); not applied during boot quirks */
  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)
  {
  	struct snd_usb_audio *chip = dev_get_drvdata(&dev->dev);
  
  	if (!chip)
  		return;
  	/*
  	 * "Playback Design" products need a 20ms delay after each
  	 * class compliant request
  	 */
  	if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
  	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
  		msleep(20);
  
  	/*
  	 * "TEAC Corp." products need a 20ms delay after each
  	 * class compliant request
  	 */
  	if (USB_ID_VENDOR(chip->usb_id) == 0x0644 &&
  	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
  		msleep(20);
  
  	/* ITF-USB DSD based DACs functionality need a delay
  	 * after each class compliant request
  	 */
  	if (is_itf_usb_dsd_dac(chip->usb_id)
  	    && (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
  		msleep(20);
  
  	/* Zoom R16/24, Logitech H650e, Jabra 550a needs a tiny delay here,
  	 * otherwise requests like get/set frequency return as failed despite
  	 * actually succeeding.
  	 */
  	if ((chip->usb_id == USB_ID(0x1686, 0x00dd) ||
  	     chip->usb_id == USB_ID(0x046d, 0x0a46) ||
  	     chip->usb_id == USB_ID(0x0b0e, 0x0349)) &&
  	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
  		usleep_range(1000, 2000);
  }
  
  /*
   * 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)
  {
  	struct usb_interface *iface;
  
  	/* Playback Designs */
  	if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
  	    USB_ID_PRODUCT(chip->usb_id) < 0x0110) {
  		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(0x1511, 0x0037): /* AURALiC VEGA */
  	case USB_ID(0x2522, 0x0012): /* LH Labs VI DAC Infinity */
  	case USB_ID(0x2772, 0x0230): /* Pro-Ject Pre Box S2 Digital */
  		if (fp->altsetting == 2)
  			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
  		break;
  
  	case USB_ID(0x0d8c, 0x0316): /* Hegel HD12 DSD */
  	case USB_ID(0x10cb, 0x0103): /* The Bit Opus #3; with fp->dsd_raw */
  	case USB_ID(0x16b0, 0x06b2): /* NuPrime DAC-10 */
  	case USB_ID(0x16d0, 0x09dd): /* Encore mDSD */
  	case USB_ID(0x16d0, 0x0733): /* Furutech ADL Stratos */
  	case USB_ID(0x16d0, 0x09db): /* NuPrime Audio DAC-9 */
  	case USB_ID(0x1db5, 0x0003): /* Bryston BDA3 */
  	case USB_ID(0x22e1, 0xca01): /* HDTA Serenade DSD */
  	case USB_ID(0x249c, 0x9326): /* M2Tech Young MkIII */
  	case USB_ID(0x2616, 0x0106): /* PS Audio NuWave DAC */
  	case USB_ID(0x2622, 0x0041): /* Audiolab M-DAC+ */
  	case USB_ID(0x27f7, 0x3002): /* W4S DAC-2v2SE */
  	case USB_ID(0x29a2, 0x0086): /* Mutec MC3+ USB */
  	case USB_ID(0x6b42, 0x0042): /* MSB Technology */
  		if (fp->altsetting == 3)
  			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
  		break;
  
  	/* Amanero Combo384 USB based DACs with native DSD support */
  	case USB_ID(0x16d0, 0x071a):  /* Amanero - Combo384 */
  	case USB_ID(0x2ab6, 0x0004):  /* T+A DAC8DSD-V2.0, MP1000E-V2.0, MP2000R-V2.0, MP2500R-V2.0, MP3100HV-V2.0 */
  	case USB_ID(0x2ab6, 0x0005):  /* T+A USB HD Audio 1 */
  	case USB_ID(0x2ab6, 0x0006):  /* T+A USB HD Audio 2 */
  		if (fp->altsetting == 2) {
  			switch (le16_to_cpu(chip->dev->descriptor.bcdDevice)) {
  			case 0x199:
  				return SNDRV_PCM_FMTBIT_DSD_U32_LE;
  			case 0x19b:
  			case 0x203:
  				return SNDRV_PCM_FMTBIT_DSD_U32_BE;
  			default:
  				break;
  			}
  		}
  		break;
  	case USB_ID(0x16d0, 0x0a23):
  		if (fp->altsetting == 2)
  			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
  		break;
  
  	default:
  		break;
  	}
  
  	/* ITF-USB DSD based DACs */
  	if (is_itf_usb_dsd_dac(chip->usb_id)) {
  		iface = usb_ifnum_to_if(chip->dev, fp->iface);
  
  		/* Altsetting 2 support native DSD if the num of altsets is
  		 * three (0-2),
  		 * Altsetting 3 support native DSD if the num of altsets is
  		 * four (0-3).
  		 */
  		if (fp->altsetting == iface->num_altsetting - 1)
  			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
  	}
  
  	/* Mostly generic method to detect many DSD-capable implementations -
  	 * from XMOS/Thesycon
  	 */
  	switch (USB_ID_VENDOR(chip->usb_id)) {
  	case 0x152a:  /* Thesycon devices */
  	case 0x20b1:  /* XMOS based devices */
  	case 0x22d9:  /* Oppo */
  	case 0x23ba:  /* Playback Designs */
  	case 0x25ce:  /* Mytek devices */
  	case 0x278b:  /* Rotel? */
  	case 0x292b:  /* Gustard/Ess based devices */
  	case 0x2ab6:  /* T+A devices */
  	case 0x3842:  /* EVGA */
  	case 0xc502:  /* HiBy devices */
  		if (fp->dsd_raw)
  			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
  		break;
  	default:
  		break;
  
  	}
  
  	return 0;
  }
  
  void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
  					  struct audioformat *fp,
  					  int stream)
  {
  	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;
  	}
  }
  