Initial import

1 files changed, 771 insertions, 0 deletions

diff --git a/sound/usb/card.c b/sound/usb/card.c
new file mode 100644
index 000000000..1fab97788
--- /dev/null
+++ b/sound/usb/card.c
@@ -0,0 +1,771 @@
+/*
+ *   (Tentative) USB Audio Driver for ALSA
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
+ *
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ *
+ *  NOTES:
+ *
+ *   - the linked URBs would be preferred but not used so far because of
+ *     the instability of unlinking.
+ *   - type II is not supported properly.  there is no device which supports
+ *     this type *correctly*.  SB extigy looks as if it supports, but it's
+ *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
+ */
+
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/usb.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/module.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "midi.h"
+#include "mixer.h"
+#include "proc.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "helper.h"
+#include "debug.h"
+#include "pcm.h"
+#include "format.h"
+#include "power.h"
+#include "stream.h"
+
+MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
+MODULE_DESCRIPTION("USB Audio");
+MODULE_LICENSE("GPL");
+MODULE_SUPPORTED_DEVICE("{{Generic,USB Audio}}");
+
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
+/* Vendor/product IDs for this card */
+static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
+static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
+static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
+static bool ignore_ctl_error;
+static bool autoclock = true;
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
+module_param_array(vid, int, NULL, 0444);
+MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
+module_param_array(pid, int, NULL, 0444);
+MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
+module_param_array(device_setup, int, NULL, 0444);
+MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
+module_param(ignore_ctl_error, bool, 0444);
+MODULE_PARM_DESC(ignore_ctl_error,
+		 "Ignore errors from USB controller for mixer interfaces.");
+module_param(autoclock, bool, 0444);
+MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
+
+/*
+ * we keep the snd_usb_audio_t instances by ourselves for merging
+ * the all interfaces on the same card as one sound device.
+ */
+
+static DEFINE_MUTEX(register_mutex);
+static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
+static struct usb_driver usb_audio_driver;
+
+/*
+ * disconnect streams
+ * called from usb_audio_disconnect()
+ */
+static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
+{
+	int idx;
+	struct snd_usb_substream *subs;
+
+	for (idx = 0; idx < 2; idx++) {
+		subs = &as->substream[idx];
+		if (!subs->num_formats)
+			continue;
+		subs->interface = -1;
+		subs->data_endpoint = NULL;
+		subs->sync_endpoint = NULL;
+	}
+}
+
+static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
+
+	if (!iface) {
+		dev_err(&dev->dev, "%u:%d : does not exist\n",
+			ctrlif, interface);
+		return -EINVAL;
+	}
+
+	alts = &iface->altsetting[0];
+	altsd = get_iface_desc(alts);
+
+	/*
+	 * Android with both accessory and audio interfaces enabled gets the
+	 * interface numbers wrong.
+	 */
+	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
+	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
+	    interface == 0 &&
+	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
+	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
+		interface = 2;
+		iface = usb_ifnum_to_if(dev, interface);
+		if (!iface)
+			return -EINVAL;
+		alts = &iface->altsetting[0];
+		altsd = get_iface_desc(alts);
+	}
+
+	if (usb_interface_claimed(iface)) {
+		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
+			ctrlif, interface);
+		return -EINVAL;
+	}
+
+	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
+	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
+	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
+		int err = snd_usbmidi_create(chip->card, iface,
+					     &chip->midi_list, NULL);
+		if (err < 0) {
+			dev_err(&dev->dev,
+				"%u:%d: cannot create sequencer device\n",
+				ctrlif, interface);
+			return -EINVAL;
+		}
+		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
+
+		return 0;
+	}
+
+	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
+	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
+	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
+		dev_dbg(&dev->dev,
+			"%u:%d: skipping non-supported interface %d\n",
+			ctrlif, interface, altsd->bInterfaceClass);
+		/* skip non-supported classes */
+		return -EINVAL;
+	}
+
+	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
+		dev_err(&dev->dev, "low speed audio streaming not supported\n");
+		return -EINVAL;
+	}
+
+	if (! snd_usb_parse_audio_interface(chip, interface)) {
+		usb_set_interface(dev, interface, 0); /* reset the current interface */
+		usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * parse audio control descriptor and create pcm/midi streams
+ */
+static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *host_iface;
+	struct usb_interface_descriptor *altsd;
+	void *control_header;
+	int i, protocol;
+
+	/* find audiocontrol interface */
+	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
+	control_header = snd_usb_find_csint_desc(host_iface->extra,
+						 host_iface->extralen,
+						 NULL, UAC_HEADER);
+	altsd = get_iface_desc(host_iface);
+	protocol = altsd->bInterfaceProtocol;
+
+	if (!control_header) {
+		dev_err(&dev->dev, "cannot find UAC_HEADER\n");
+		return -EINVAL;
+	}
+
+	switch (protocol) {
+	default:
+		dev_warn(&dev->dev,
+			 "unknown interface protocol %#02x, assuming v1\n",
+			 protocol);
+		/* fall through */
+
+	case UAC_VERSION_1: {
+		struct uac1_ac_header_descriptor *h1 = control_header;
+
+		if (!h1->bInCollection) {
+			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
+			return -EINVAL;
+		}
+
+		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
+			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
+			return -EINVAL;
+		}
+
+		for (i = 0; i < h1->bInCollection; i++)
+			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
+
+		break;
+	}
+
+	case UAC_VERSION_2: {
+		struct usb_interface_assoc_descriptor *assoc =
+			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
+
+		if (!assoc) {
+			/*
+			 * Firmware writers cannot count to three.  So to find
+			 * the IAD on the NuForce UDH-100, also check the next
+			 * interface.
+			 */
+			struct usb_interface *iface =
+				usb_ifnum_to_if(dev, ctrlif + 1);
+			if (iface &&
+			    iface->intf_assoc &&
+			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
+			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
+				assoc = iface->intf_assoc;
+		}
+
+		if (!assoc) {
+			dev_err(&dev->dev, "Audio class v2 interfaces need an interface association\n");
+			return -EINVAL;
+		}
+
+		for (i = 0; i < assoc->bInterfaceCount; i++) {
+			int intf = assoc->bFirstInterface + i;
+
+			if (intf != ctrlif)
+				snd_usb_create_stream(chip, ctrlif, intf);
+		}
+
+		break;
+	}
+	}
+
+	return 0;
+}
+
+/*
+ * free the chip instance
+ *
+ * here we have to do not much, since pcm and controls are already freed
+ *
+ */
+
+static int snd_usb_audio_free(struct snd_usb_audio *chip)
+{
+	struct snd_usb_endpoint *ep, *n;
+
+	list_for_each_entry_safe(ep, n, &chip->ep_list, list)
+		snd_usb_endpoint_free(ep);
+
+	mutex_destroy(&chip->mutex);
+	kfree(chip);
+	return 0;
+}
+
+static int snd_usb_audio_dev_free(struct snd_device *device)
+{
+	struct snd_usb_audio *chip = device->device_data;
+	return snd_usb_audio_free(chip);
+}
+
+/*
+ * create a chip instance and set its names.
+ */
+static int snd_usb_audio_create(struct usb_interface *intf,
+				struct usb_device *dev, int idx,
+				const struct snd_usb_audio_quirk *quirk,
+				struct snd_usb_audio **rchip)
+{
+	struct snd_card *card;
+	struct snd_usb_audio *chip;
+	int err, len;
+	char component[14];
+	static struct snd_device_ops ops = {
+		.dev_free =	snd_usb_audio_dev_free,
+	};
+
+	*rchip = NULL;
+
+	switch (snd_usb_get_speed(dev)) {
+	case USB_SPEED_LOW:
+	case USB_SPEED_FULL:
+	case USB_SPEED_HIGH:
+	case USB_SPEED_WIRELESS:
+	case USB_SPEED_SUPER:
+		break;
+	default:
+		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
+		return -ENXIO;
+	}
+
+	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
+			   0, &card);
+	if (err < 0) {
+		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
+		return err;
+	}
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	if (! chip) {
+		snd_card_free(card);
+		return -ENOMEM;
+	}
+
+	mutex_init(&chip->mutex);
+	init_rwsem(&chip->shutdown_rwsem);
+	chip->index = idx;
+	chip->dev = dev;
+	chip->card = card;
+	chip->setup = device_setup[idx];
+	chip->autoclock = autoclock;
+	chip->probing = 1;
+
+	chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
+			      le16_to_cpu(dev->descriptor.idProduct));
+	INIT_LIST_HEAD(&chip->pcm_list);
+	INIT_LIST_HEAD(&chip->ep_list);
+	INIT_LIST_HEAD(&chip->midi_list);
+	INIT_LIST_HEAD(&chip->mixer_list);
+
+	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops)) < 0) {
+		snd_usb_audio_free(chip);
+		snd_card_free(card);
+		return err;
+	}
+
+	strcpy(card->driver, "USB-Audio");
+	sprintf(component, "USB%04x:%04x",
+		USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
+	snd_component_add(card, component);
+
+	/* retrieve the device string as shortname */
+	if (quirk && quirk->product_name && *quirk->product_name) {
+		strlcpy(card->shortname, quirk->product_name, sizeof(card->shortname));
+	} else {
+		if (!dev->descriptor.iProduct ||
+		    usb_string(dev, dev->descriptor.iProduct,
+		    card->shortname, sizeof(card->shortname)) <= 0) {
+			/* no name available from anywhere, so use ID */
+			sprintf(card->shortname, "USB Device %#04x:%#04x",
+				USB_ID_VENDOR(chip->usb_id),
+				USB_ID_PRODUCT(chip->usb_id));
+		}
+	}
+	strim(card->shortname);
+
+	/* retrieve the vendor and device strings as longname */
+	if (quirk && quirk->vendor_name && *quirk->vendor_name) {
+		len = strlcpy(card->longname, quirk->vendor_name, sizeof(card->longname));
+	} else {
+		if (dev->descriptor.iManufacturer)
+			len = usb_string(dev, dev->descriptor.iManufacturer,
+					 card->longname, sizeof(card->longname));
+		else
+			len = 0;
+		/* we don't really care if there isn't any vendor string */
+	}
+	if (len > 0) {
+		strim(card->longname);
+		if (*card->longname)
+			strlcat(card->longname, " ", sizeof(card->longname));
+	}
+
+	strlcat(card->longname, card->shortname, sizeof(card->longname));
+
+	len = strlcat(card->longname, " at ", sizeof(card->longname));
+
+	if (len < sizeof(card->longname))
+		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
+
+	switch (snd_usb_get_speed(dev)) {
+	case USB_SPEED_LOW:
+		strlcat(card->longname, ", low speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_FULL:
+		strlcat(card->longname, ", full speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_HIGH:
+		strlcat(card->longname, ", high speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_SUPER:
+		strlcat(card->longname, ", super speed", sizeof(card->longname));
+		break;
+	default:
+		break;
+	}
+
+	snd_usb_audio_create_proc(chip);
+
+	*rchip = chip;
+	return 0;
+}
+
+/*
+ * probe the active usb device
+ *
+ * note that this can be called multiple times per a device, when it
+ * includes multiple audio control interfaces.
+ *
+ * thus we check the usb device pointer and creates the card instance
+ * only at the first time.  the successive calls of this function will
+ * append the pcm interface to the corresponding card.
+ */
+static int usb_audio_probe(struct usb_interface *intf,
+			   const struct usb_device_id *usb_id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	const struct snd_usb_audio_quirk *quirk =
+		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
+	struct snd_usb_audio *chip;
+	int i, err;
+	struct usb_host_interface *alts;
+	int ifnum;
+	u32 id;
+
+	alts = &intf->altsetting[0];
+	ifnum = get_iface_desc(alts)->bInterfaceNumber;
+	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
+		    le16_to_cpu(dev->descriptor.idProduct));
+	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
+		return -ENXIO;
+
+	err = snd_usb_apply_boot_quirk(dev, intf, quirk);
+	if (err < 0)
+		return err;
+
+	/*
+	 * found a config.  now register to ALSA
+	 */
+
+	/* check whether it's already registered */
+	chip = NULL;
+	mutex_lock(&register_mutex);
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (usb_chip[i] && usb_chip[i]->dev == dev) {
+			if (usb_chip[i]->shutdown) {
+				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
+				err = -EIO;
+				goto __error;
+			}
+			chip = usb_chip[i];
+			chip->probing = 1;
+			break;
+		}
+	}
+	if (! chip) {
+		/* it's a fresh one.
+		 * now look for an empty slot and create a new card instance
+		 */
+		for (i = 0; i < SNDRV_CARDS; i++)
+			if (enable[i] && ! usb_chip[i] &&
+			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
+			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
+				err = snd_usb_audio_create(intf, dev, i, quirk,
+							   &chip);
+				if (err < 0)
+					goto __error;
+				chip->pm_intf = intf;
+				break;
+			}
+		if (!chip) {
+			dev_err(&dev->dev, "no available usb audio device\n");
+			err = -ENODEV;
+			goto __error;
+		}
+	}
+
+	/*
+	 * For devices with more than one control interface, we assume the
+	 * first contains the audio controls. We might need a more specific
+	 * check here in the future.
+	 */
+	if (!chip->ctrl_intf)
+		chip->ctrl_intf = alts;
+
+	chip->txfr_quirk = 0;
+	err = 1; /* continue */
+	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
+		/* need some special handlings */
+		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
+		if (err < 0)
+			goto __error;
+	}
+
+	if (err > 0) {
+		/* create normal USB audio interfaces */
+		err = snd_usb_create_streams(chip, ifnum);
+		if (err < 0)
+			goto __error;
+		err = snd_usb_create_mixer(chip, ifnum, ignore_ctl_error);
+		if (err < 0)
+			goto __error;
+	}
+
+	/* we are allowed to call snd_card_register() many times */
+	err = snd_card_register(chip->card);
+	if (err < 0)
+		goto __error;
+
+	usb_chip[chip->index] = chip;
+	chip->num_interfaces++;
+	chip->probing = 0;
+	usb_set_intfdata(intf, chip);
+	mutex_unlock(&register_mutex);
+	return 0;
+
+ __error:
+	if (chip) {
+		if (!chip->num_interfaces)
+			snd_card_free(chip->card);
+		chip->probing = 0;
+	}
+	mutex_unlock(&register_mutex);
+	return err;
+}
+
+/*
+ * we need to take care of counter, since disconnection can be called also
+ * many times as well as usb_audio_probe().
+ */
+static void usb_audio_disconnect(struct usb_interface *intf)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct snd_card *card;
+	struct list_head *p;
+	bool was_shutdown;
+
+	if (chip == (void *)-1L)
+		return;
+
+	card = chip->card;
+	down_write(&chip->shutdown_rwsem);
+	was_shutdown = chip->shutdown;
+	chip->shutdown = 1;
+	up_write(&chip->shutdown_rwsem);
+
+	mutex_lock(&register_mutex);
+	if (!was_shutdown) {
+		struct snd_usb_stream *as;
+		struct snd_usb_endpoint *ep;
+		struct usb_mixer_interface *mixer;
+
+		snd_card_disconnect(card);
+		/* release the pcm resources */
+		list_for_each_entry(as, &chip->pcm_list, list) {
+			snd_usb_stream_disconnect(as);
+		}
+		/* release the endpoint resources */
+		list_for_each_entry(ep, &chip->ep_list, list) {
+			snd_usb_endpoint_release(ep);
+		}
+		/* release the midi resources */
+		list_for_each(p, &chip->midi_list) {
+			snd_usbmidi_disconnect(p);
+		}
+		/* release mixer resources */
+		list_for_each_entry(mixer, &chip->mixer_list, list) {
+			snd_usb_mixer_disconnect(mixer);
+		}
+	}
+
+	chip->num_interfaces--;
+	if (chip->num_interfaces <= 0) {
+		usb_chip[chip->index] = NULL;
+		mutex_unlock(&register_mutex);
+		snd_card_free_when_closed(card);
+	} else {
+		mutex_unlock(&register_mutex);
+	}
+}
+
+#ifdef CONFIG_PM
+
+int snd_usb_autoresume(struct snd_usb_audio *chip)
+{
+	int err = -ENODEV;
+
+	down_read(&chip->shutdown_rwsem);
+	if (chip->probing && chip->in_pm)
+		err = 0;
+	else if (!chip->shutdown)
+		err = usb_autopm_get_interface(chip->pm_intf);
+	up_read(&chip->shutdown_rwsem);
+
+	return err;
+}
+
+void snd_usb_autosuspend(struct snd_usb_audio *chip)
+{
+	down_read(&chip->shutdown_rwsem);
+	if (!chip->shutdown && !chip->probing && !chip->in_pm)
+		usb_autopm_put_interface(chip->pm_intf);
+	up_read(&chip->shutdown_rwsem);
+}
+
+static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct snd_usb_stream *as;
+	struct usb_mixer_interface *mixer;
+	struct list_head *p;
+
+	if (chip == (void *)-1L)
+		return 0;
+
+	if (!PMSG_IS_AUTO(message)) {
+		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
+		if (!chip->num_suspended_intf++) {
+			list_for_each_entry(as, &chip->pcm_list, list) {
+				snd_pcm_suspend_all(as->pcm);
+				as->substream[0].need_setup_ep =
+					as->substream[1].need_setup_ep = true;
+			}
+			list_for_each(p, &chip->midi_list) {
+				snd_usbmidi_suspend(p);
+			}
+		}
+	} else {
+		/*
+		 * otherwise we keep the rest of the system in the dark
+		 * to keep this transparent
+		 */
+		if (!chip->num_suspended_intf++)
+			chip->autosuspended = 1;
+	}
+
+	if (chip->num_suspended_intf == 1)
+		list_for_each_entry(mixer, &chip->mixer_list, list)
+			snd_usb_mixer_suspend(mixer);
+
+	return 0;
+}
+
+static int __usb_audio_resume(struct usb_interface *intf, bool reset_resume)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct usb_mixer_interface *mixer;
+	struct list_head *p;
+	int err = 0;
+
+	if (chip == (void *)-1L)
+		return 0;
+	if (--chip->num_suspended_intf)
+		return 0;
+
+	chip->in_pm = 1;
+	/*
+	 * ALSA leaves material resumption to user space
+	 * we just notify and restart the mixers
+	 */
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		err = snd_usb_mixer_resume(mixer, reset_resume);
+		if (err < 0)
+			goto err_out;
+	}
+
+	list_for_each(p, &chip->midi_list) {
+		snd_usbmidi_resume(p);
+	}
+
+	if (!chip->autosuspended)
+		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
+	chip->autosuspended = 0;
+
+err_out:
+	chip->in_pm = 0;
+	return err;
+}
+
+static int usb_audio_resume(struct usb_interface *intf)
+{
+	return __usb_audio_resume(intf, false);
+}
+
+static int usb_audio_reset_resume(struct usb_interface *intf)
+{
+	return __usb_audio_resume(intf, true);
+}
+#else
+#define usb_audio_suspend	NULL
+#define usb_audio_resume	NULL
+#define usb_audio_reset_resume	NULL
+#endif		/* CONFIG_PM */
+
+static struct usb_device_id usb_audio_ids [] = {
+#include "quirks-table.h"
+    { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
+      .bInterfaceClass = USB_CLASS_AUDIO,
+      .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
+    { }						/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, usb_audio_ids);
+
+/*
+ * entry point for linux usb interface
+ */
+
+static struct usb_driver usb_audio_driver = {
+	.name =		"snd-usb-audio",
+	.probe =	usb_audio_probe,
+	.disconnect =	usb_audio_disconnect,
+	.suspend =	usb_audio_suspend,
+	.resume =	usb_audio_resume,
+	.reset_resume =	usb_audio_reset_resume,
+	.id_table =	usb_audio_ids,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(usb_audio_driver);