aboutsummaryrefslogblamecommitdiffstats
path: root/sound/usb/usbaudio.c
blob: 2ead878bcb8f4793113db63a685caa026955b2eb (plain) (tree)
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852










































                                                                             
                            



                         
                          

































                                                                                              
                                 
















                                                                
                         
                                                               


























                                                                                     
                                                                              


                                                       





















                                                                                                          
                                                                           










                                                                                         
                                                                                    


                                                            
                                                                                                    






                                                                                               

                                                                                   




                                                                                              
                                                                               



























                                                                                
                                                                 







                                                                         
                                                                 




                                                              
                                                               




                                                              
                                                               
















                                                               
 
                                                                         




                                          














                                                                  
 
                                                                         





                                          




























                                                                    



                                                                         



                                                                  
         
                                           
                                              


























                                                                                                               
                               


















                                                                                                       



                                                                    









                                                                                      
         

                                                            













                                                                 

                                                           
                                                                         

                                          












                                                                   

                                                           
                                                                         

                                          












                                                               
                       

                            


                                                                   



                                                                               
                 














                                                                  
                       

                            


                                                                         




                                                                               







                                     



                                                                             







                                                           
                               












                                                                         

                                                                      








                                                                



                                                                    
                                                                   







                                                                       



                                                                      

                                                                       


                                                                          
                                      
                         
                 



                                                                               
         








                                                                           
                


                                                                     
         


                                                         

                                                    





                                                                         




                                       
                  




                                                          


                 









                                                                        














































































                                                                                        



































                                                                               





















                                                                               
                                          
                                                          
                                    








                                                                                   
                                                  
                                                                  
                                            





































































                                                                                                             
                                                                  


















                                                                         
                                                 










                                                                                







                                                                       































                                                                                            



                                                                     


                                     
















                                                                        


                                                       










                                                                                    
                                                                            






                                                            


                                                           
                                            






                                                                            
         
                        





                                                      



                                                           
                                          
 
                          
                                    


                                                                        
                              
                                  
 
                                                
                          



                                                                    
                                                                       
                                   
                                                

                                                                     





                                                                       


                                                   

















                                                                
                                                                          

















                                                             
                                       
                                                      

                                                                  
                                                               






                                                                               
                                              
                                                                                
                                                           





                                                                               



                                                                              



                                                             

                                                              

                                                   
                                                                        
                                                                      
                                                           
                                                      

                                                                         
                                                      
                                                                   




                                                                                            



                                        














































































































































































                                                                                                                        





                                                                          




































                                                                                                                   



                                                                                   
                                                                        
                                               




                                                                                  






































                                                                                            

                                                                           






















































                                                                                                                                
                                                      





















                                                                                 
                             











                                            




                                                              
                                            
                                   
                                           





                                           




                                                              
                                            
                                   
                                           




































































































































































































































































































































































































                                                                                                        
                                                 










                                              
                                                 





































































































































































                                                                                             
                                                                              

                                                                          

                                                                     












































                                                                                                   


                                                                               







                                                             












































                                                                                 





















































































                                                                                        
                                                                              
 


                                                                              
                                 


                                                                 












                                           
                                                                                   











                                                                                                 
                                                                          



                                                                                                       
                                                                                







                                                               
                                                           




                                                                                              
                                                           








                                                                                                       

                                                                               




                                              
                                                           














                                                                               
                                                                                 















                                                                   
                                                                                  




                                                                            
                                                                                 













































                                                                                          
                                                                              










                                                                           
                                                                              






                                                                       
                                                                                       

                          
                                                          




                                      
                                                                               













                                                                                                             
                                                                                 







                                                                                                         
                                                                                      

 
                                                                            






                                                                         
                                                                  

                                
                                                                   


                                                                                        
                                                                                 





                              
                                                          


                                                                 

                                                     
                                                  

                                                        
                                  


























































































                                                                                                                                
                                                                                     


                                                                             



                                                     

                                                                     



                                                                           


                                                                          

                                                                                    



                                                                                



                                                                            




                                                                
                              


                                                
                                                                            
























                                                                                                                     
                                                             









































































































































































                                                                                                                                                

                                                                      




































                                                                      
                                                           



















































                                                                             


                                                                  











































































                                                                                          






                                                                     
































                                                                                          

                                                               










                                                                                


                 












                                                                       





















                                                                                   




















                                                                                              

                                                          



























































                                                                                         
                                                  







                                    

                                                                      

                                         
                                          








                                                                               
                                                                           










                                                                                       

                                                              





























                                                                                           
























                                                                                                
               


                                                       

                                                            





                                                                  
                                           



                                                             




                                                             




























                                                                                                                                    

                                                                             


                                                                                     
                                                                         






























































                                                                               
                                                     


                                                    
                                                  
                 



                                                     

                                             
                                    












































                                                                        
/*
 *   (Tentative) USB Audio Driver for ALSA
 *
 *   Main and PCM part
 *
 *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
 *
 *   Many codes borrowed from audio.c by
 *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
 *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *
 *  NOTES:
 *
 *   - async unlink should be used for avoiding the sleep inside lock.
 *     2.4.22 usb-uhci seems buggy for async unlinking and results in
 *     oops.  in such a cse, pass async_unlink=0 option.
 *   - 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 <sound/driver.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.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"


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 int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;	/* Enable this card */
static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 }; /* Vendor ID for this card */
static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 }; /* Product ID for this card */
static int nrpacks = 4;		/* max. number of packets per urb */
static int async_unlink = 1;

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(nrpacks, int, 0644);
MODULE_PARM_DESC(nrpacks, "Max. number of packets per URB.");
module_param(async_unlink, bool, 0444);
MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");


/*
 * debug the h/w constraints
 */
/* #define HW_CONST_DEBUG */


/*
 *
 */

#define MAX_PACKS	10
#define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
#define MAX_URBS	8
#define SYNC_URBS	4	/* always four urbs for sync */
#define MIN_PACKS_URB	1	/* minimum 1 packet per urb */

typedef struct snd_usb_substream snd_usb_substream_t;
typedef struct snd_usb_stream snd_usb_stream_t;
typedef struct snd_urb_ctx snd_urb_ctx_t;

struct audioformat {
	struct list_head list;
	snd_pcm_format_t format;	/* format type */
	unsigned int channels;		/* # channels */
	unsigned int fmt_type;		/* USB audio format type (1-3) */
	unsigned int frame_size;	/* samples per frame for non-audio */
	int iface;			/* interface number */
	unsigned char altsetting;	/* corresponding alternate setting */
	unsigned char altset_idx;	/* array index of altenate setting */
	unsigned char attributes;	/* corresponding attributes of cs endpoint */
	unsigned char endpoint;		/* endpoint */
	unsigned char ep_attr;		/* endpoint attributes */
	unsigned int maxpacksize;	/* max. packet size */
	unsigned int rates;		/* rate bitmasks */
	unsigned int rate_min, rate_max;	/* min/max rates */
	unsigned int nr_rates;		/* number of rate table entries */
	unsigned int *rate_table;	/* rate table */
};

struct snd_urb_ctx {
	struct urb *urb;
	unsigned int buffer_size;	/* size of data buffer, if data URB */
	snd_usb_substream_t *subs;
	int index;	/* index for urb array */
	int packets;	/* number of packets per urb */
};

struct snd_urb_ops {
	int (*prepare)(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *u);
	int (*retire)(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *u);
	int (*prepare_sync)(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *u);
	int (*retire_sync)(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime, struct urb *u);
};

struct snd_usb_substream {
	snd_usb_stream_t *stream;
	struct usb_device *dev;
	snd_pcm_substream_t *pcm_substream;
	int direction;	/* playback or capture */
	int interface;	/* current interface */
	int endpoint;	/* assigned endpoint */
	struct audioformat *cur_audiofmt;	/* current audioformat pointer (for hw_params callback) */
	unsigned int cur_rate;		/* current rate (for hw_params callback) */
	unsigned int period_bytes;	/* current period bytes (for hw_params callback) */
	unsigned int format;     /* USB data format */
	unsigned int datapipe;   /* the data i/o pipe */
	unsigned int syncpipe;   /* 1 - async out or adaptive in */
	unsigned int datainterval;	/* log_2 of data packet interval */
	unsigned int syncinterval;  /* P for adaptive mode, 0 otherwise */
	unsigned int freqn;      /* nominal sampling rate in fs/fps in Q16.16 format */
	unsigned int freqm;      /* momentary sampling rate in fs/fps in Q16.16 format */
	unsigned int freqmax;    /* maximum sampling rate, used for buffer management */
	unsigned int phase;      /* phase accumulator */
	unsigned int maxpacksize;	/* max packet size in bytes */
	unsigned int maxframesize;	/* max packet size in frames */
	unsigned int curpacksize;	/* current packet size in bytes (for capture) */
	unsigned int curframesize;	/* current packet size in frames (for capture) */
	unsigned int fill_max: 1;	/* fill max packet size always */
	unsigned int fmt_type;		/* USB audio format type (1-3) */
	unsigned int packs_per_ms;	/* packets per millisecond (for playback) */

	unsigned int running: 1;	/* running status */

	unsigned int hwptr_done;			/* processed frame position in the buffer */
	unsigned int transfer_done;		/* processed frames since last period update */
	unsigned long active_mask;	/* bitmask of active urbs */
	unsigned long unlink_mask;	/* bitmask of unlinked urbs */

	unsigned int nurbs;			/* # urbs */
	snd_urb_ctx_t dataurb[MAX_URBS];	/* data urb table */
	snd_urb_ctx_t syncurb[SYNC_URBS];	/* sync urb table */
	char *syncbuf;				/* sync buffer for all sync URBs */
	dma_addr_t sync_dma;			/* DMA address of syncbuf */

	u64 formats;			/* format bitmasks (all or'ed) */
	unsigned int num_formats;		/* number of supported audio formats (list) */
	struct list_head fmt_list;	/* format list */
	spinlock_t lock;
	struct tasklet_struct start_period_elapsed;	/* for start trigger */

	struct snd_urb_ops ops;		/* callbacks (must be filled at init) */
};


struct snd_usb_stream {
	snd_usb_audio_t *chip;
	snd_pcm_t *pcm;
	int pcm_index;
	unsigned int fmt_type;		/* USB audio format type (1-3) */
	snd_usb_substream_t substream[2];
	struct list_head list;
};


/*
 * we keep the snd_usb_audio_t instances by ourselves for merging
 * the all interfaces on the same card as one sound device.
 */

static DECLARE_MUTEX(register_mutex);
static snd_usb_audio_t *usb_chip[SNDRV_CARDS];


/*
 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 * this will overflow at approx 524 kHz
 */
static inline unsigned get_usb_full_speed_rate(unsigned int rate)
{
	return ((rate << 13) + 62) / 125;
}

/*
 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 * this will overflow at approx 4 MHz
 */
static inline unsigned get_usb_high_speed_rate(unsigned int rate)
{
	return ((rate << 10) + 62) / 125;
}

/* convert our full speed USB rate into sampling rate in Hz */
static inline unsigned get_full_speed_hz(unsigned int usb_rate)
{
	return (usb_rate * 125 + (1 << 12)) >> 13;
}

/* convert our high speed USB rate into sampling rate in Hz */
static inline unsigned get_high_speed_hz(unsigned int usb_rate)
{
	return (usb_rate * 125 + (1 << 9)) >> 10;
}


/*
 * prepare urb for full speed capture sync pipe
 *
 * fill the length and offset of each urb descriptor.
 * the fixed 10.14 frequency is passed through the pipe.
 */
static int prepare_capture_sync_urb(snd_usb_substream_t *subs,
				    snd_pcm_runtime_t *runtime,
				    struct urb *urb)
{
	unsigned char *cp = urb->transfer_buffer;
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 3;
	urb->iso_frame_desc[0].offset = 0;
	cp[0] = subs->freqn >> 2;
	cp[1] = subs->freqn >> 10;
	cp[2] = subs->freqn >> 18;
	return 0;
}

/*
 * prepare urb for high speed capture sync pipe
 *
 * fill the length and offset of each urb descriptor.
 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
 */
static int prepare_capture_sync_urb_hs(snd_usb_substream_t *subs,
				       snd_pcm_runtime_t *runtime,
				       struct urb *urb)
{
	unsigned char *cp = urb->transfer_buffer;
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 4;
	urb->iso_frame_desc[0].offset = 0;
	cp[0] = subs->freqn;
	cp[1] = subs->freqn >> 8;
	cp[2] = subs->freqn >> 16;
	cp[3] = subs->freqn >> 24;
	return 0;
}

/*
 * process after capture sync complete
 * - nothing to do
 */
static int retire_capture_sync_urb(snd_usb_substream_t *subs,
				   snd_pcm_runtime_t *runtime,
				   struct urb *urb)
{
	return 0;
}

/*
 * prepare urb for capture data pipe
 *
 * fill the offset and length of each descriptor.
 *
 * we use a temporary buffer to write the captured data.
 * since the length of written data is determined by host, we cannot
 * write onto the pcm buffer directly...  the data is thus copied
 * later at complete callback to the global buffer.
 */
static int prepare_capture_urb(snd_usb_substream_t *subs,
			       snd_pcm_runtime_t *runtime,
			       struct urb *urb)
{
	int i, offs;
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;

	offs = 0;
	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	for (i = 0; i < ctx->packets; i++) {
		urb->iso_frame_desc[i].offset = offs;
		urb->iso_frame_desc[i].length = subs->curpacksize;
		offs += subs->curpacksize;
	}
	urb->transfer_buffer_length = offs;
	urb->number_of_packets = ctx->packets;
#if 0 // for check
	if (! urb->bandwidth) {
		int bustime;
		bustime = usb_check_bandwidth(urb->dev, urb);
		if (bustime < 0)
			return bustime;
		printk("urb %d: bandwidth = %d (packets = %d)\n", ctx->index, bustime, urb->number_of_packets);
		usb_claim_bandwidth(urb->dev, urb, bustime, 1);
	}
#endif // for check
	return 0;
}

/*
 * process after capture complete
 *
 * copy the data from each desctiptor to the pcm buffer, and
 * update the current position.
 */
static int retire_capture_urb(snd_usb_substream_t *subs,
			      snd_pcm_runtime_t *runtime,
			      struct urb *urb)
{
	unsigned long flags;
	unsigned char *cp;
	int i;
	unsigned int stride, len, oldptr;
	int period_elapsed = 0;

	stride = runtime->frame_bits >> 3;

	for (i = 0; i < urb->number_of_packets; i++) {
		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
		if (urb->iso_frame_desc[i].status) {
			snd_printd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
			// continue;
		}
		len = urb->iso_frame_desc[i].actual_length / stride;
		if (! len)
			continue;
		/* update the current pointer */
		spin_lock_irqsave(&subs->lock, flags);
		oldptr = subs->hwptr_done;
		subs->hwptr_done += len;
		if (subs->hwptr_done >= runtime->buffer_size)
			subs->hwptr_done -= runtime->buffer_size;
		subs->transfer_done += len;
		if (subs->transfer_done >= runtime->period_size) {
			subs->transfer_done -= runtime->period_size;
			period_elapsed = 1;
		}
		spin_unlock_irqrestore(&subs->lock, flags);
		/* copy a data chunk */
		if (oldptr + len > runtime->buffer_size) {
			unsigned int cnt = runtime->buffer_size - oldptr;
			unsigned int blen = cnt * stride;
			memcpy(runtime->dma_area + oldptr * stride, cp, blen);
			memcpy(runtime->dma_area, cp + blen, len * stride - blen);
		} else {
			memcpy(runtime->dma_area + oldptr * stride, cp, len * stride);
		}
	}
	if (period_elapsed)
		snd_pcm_period_elapsed(subs->pcm_substream);
	return 0;
}


/*
 * prepare urb for full speed playback sync pipe
 *
 * set up the offset and length to receive the current frequency.
 */

static int prepare_playback_sync_urb(snd_usb_substream_t *subs,
				     snd_pcm_runtime_t *runtime,
				     struct urb *urb)
{
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 3;
	urb->iso_frame_desc[0].offset = 0;
	return 0;
}

/*
 * prepare urb for high speed playback sync pipe
 *
 * set up the offset and length to receive the current frequency.
 */

static int prepare_playback_sync_urb_hs(snd_usb_substream_t *subs,
					snd_pcm_runtime_t *runtime,
					struct urb *urb)
{
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 4;
	urb->iso_frame_desc[0].offset = 0;
	return 0;
}

/*
 * process after full speed playback sync complete
 *
 * retrieve the current 10.14 frequency from pipe, and set it.
 * the value is referred in prepare_playback_urb().
 */
static int retire_playback_sync_urb(snd_usb_substream_t *subs,
				    snd_pcm_runtime_t *runtime,
				    struct urb *urb)
{
	unsigned int f;
	unsigned long flags;

	if (urb->iso_frame_desc[0].status == 0 &&
	    urb->iso_frame_desc[0].actual_length == 3) {
		f = combine_triple((u8*)urb->transfer_buffer) << 2;
		if (f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax) {
			spin_lock_irqsave(&subs->lock, flags);
			subs->freqm = f;
			spin_unlock_irqrestore(&subs->lock, flags);
		}
	}

	return 0;
}

/*
 * process after high speed playback sync complete
 *
 * retrieve the current 12.13 frequency from pipe, and set it.
 * the value is referred in prepare_playback_urb().
 */
static int retire_playback_sync_urb_hs(snd_usb_substream_t *subs,
				       snd_pcm_runtime_t *runtime,
				       struct urb *urb)
{
	unsigned int f;
	unsigned long flags;

	if (urb->iso_frame_desc[0].status == 0 &&
	    urb->iso_frame_desc[0].actual_length == 4) {
		f = combine_quad((u8*)urb->transfer_buffer) & 0x0fffffff;
		if (f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax) {
			spin_lock_irqsave(&subs->lock, flags);
			subs->freqm = f;
			spin_unlock_irqrestore(&subs->lock, flags);
		}
	}

	return 0;
}

/*
 * prepare urb for playback data pipe
 *
 * Since a URB can handle only a single linear buffer, we must use double
 * buffering when the data to be transferred overflows the buffer boundary.
 * To avoid inconsistencies when updating hwptr_done, we use double buffering
 * for all URBs.
 */
static int prepare_playback_urb(snd_usb_substream_t *subs,
				snd_pcm_runtime_t *runtime,
				struct urb *urb)
{
	int i, stride, offs;
	unsigned int counts;
	unsigned long flags;
	int period_elapsed = 0;
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;

	stride = runtime->frame_bits >> 3;

	offs = 0;
	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->number_of_packets = 0;
	spin_lock_irqsave(&subs->lock, flags);
	for (i = 0; i < ctx->packets; i++) {
		/* calculate the size of a packet */
		if (subs->fill_max)
			counts = subs->maxframesize; /* fixed */
		else {
			subs->phase = (subs->phase & 0xffff)
				+ (subs->freqm << subs->datainterval);
			counts = subs->phase >> 16;
			if (counts > subs->maxframesize)
				counts = subs->maxframesize;
		}
		/* set up descriptor */
		urb->iso_frame_desc[i].offset = offs * stride;
		urb->iso_frame_desc[i].length = counts * stride;
		offs += counts;
		urb->number_of_packets++;
		subs->transfer_done += counts;
		if (subs->transfer_done >= runtime->period_size) {
			subs->transfer_done -= runtime->period_size;
			period_elapsed = 1;
			if (subs->fmt_type == USB_FORMAT_TYPE_II) {
				if (subs->transfer_done > 0) {
					/* FIXME: fill-max mode is not
					 * supported yet */
					offs -= subs->transfer_done;
					counts -= subs->transfer_done;
					urb->iso_frame_desc[i].length =
						counts * stride;
					subs->transfer_done = 0;
				}
				i++;
				if (i < ctx->packets) {
					/* add a transfer delimiter */
					urb->iso_frame_desc[i].offset =
						offs * stride;
					urb->iso_frame_desc[i].length = 0;
					urb->number_of_packets++;
				}
				break;
			}
 		}
		/* finish at the frame boundary at/after the period boundary */
		if (period_elapsed &&
		    (i & (subs->packs_per_ms - 1)) == subs->packs_per_ms - 1)
			break;
	}
	if (subs->hwptr_done + offs > runtime->buffer_size) {
		/* err, the transferred area goes over buffer boundary. */
		unsigned int len = runtime->buffer_size - subs->hwptr_done;
		memcpy(urb->transfer_buffer,
		       runtime->dma_area + subs->hwptr_done * stride,
		       len * stride);
		memcpy(urb->transfer_buffer + len * stride,
		       runtime->dma_area,
		       (offs - len) * stride);
	} else {
		memcpy(urb->transfer_buffer,
		       runtime->dma_area + subs->hwptr_done * stride,
		       offs * stride);
	}
	subs->hwptr_done += offs;
	if (subs->hwptr_done >= runtime->buffer_size)
		subs->hwptr_done -= runtime->buffer_size;
	spin_unlock_irqrestore(&subs->lock, flags);
	urb->transfer_buffer_length = offs * stride;
	if (period_elapsed) {
		if (likely(subs->running))
			snd_pcm_period_elapsed(subs->pcm_substream);
		else
			tasklet_hi_schedule(&subs->start_period_elapsed);
	}
	return 0;
}

/*
 * process after playback data complete
 * - nothing to do
 */
static int retire_playback_urb(snd_usb_substream_t *subs,
			       snd_pcm_runtime_t *runtime,
			       struct urb *urb)
{
	return 0;
}

/*
 * Delay the snd_pcm_period_elapsed() call until after the start trigger
 * callback so that we're not longer in the substream's lock.
 */
static void start_period_elapsed(unsigned long data)
{
	snd_usb_substream_t *subs = (snd_usb_substream_t *)data;
	snd_pcm_period_elapsed(subs->pcm_substream);
}


/*
 */
static struct snd_urb_ops audio_urb_ops[2] = {
	{
		.prepare =	prepare_playback_urb,
		.retire =	retire_playback_urb,
		.prepare_sync =	prepare_playback_sync_urb,
		.retire_sync =	retire_playback_sync_urb,
	},
	{
		.prepare =	prepare_capture_urb,
		.retire =	retire_capture_urb,
		.prepare_sync =	prepare_capture_sync_urb,
		.retire_sync =	retire_capture_sync_urb,
	},
};

static struct snd_urb_ops audio_urb_ops_high_speed[2] = {
	{
		.prepare =	prepare_playback_urb,
		.retire =	retire_playback_urb,
		.prepare_sync =	prepare_playback_sync_urb_hs,
		.retire_sync =	retire_playback_sync_urb_hs,
	},
	{
		.prepare =	prepare_capture_urb,
		.retire =	retire_capture_urb,
		.prepare_sync =	prepare_capture_sync_urb_hs,
		.retire_sync =	retire_capture_sync_urb,
	},
};

/*
 * complete callback from data urb
 */
static void snd_complete_urb(struct urb *urb, struct pt_regs *regs)
{
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
	snd_usb_substream_t *subs = ctx->subs;
	snd_pcm_substream_t *substream = ctx->subs->pcm_substream;
	int err = 0;

	if ((subs->running && subs->ops.retire(subs, substream->runtime, urb)) ||
	    ! subs->running || /* can be stopped during retire callback */
	    (err = subs->ops.prepare(subs, substream->runtime, urb)) < 0 ||
	    (err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
		clear_bit(ctx->index, &subs->active_mask);
		if (err < 0) {
			snd_printd(KERN_ERR "cannot submit urb (err = %d)\n", err);
			snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
		}
	}
}


/*
 * complete callback from sync urb
 */
static void snd_complete_sync_urb(struct urb *urb, struct pt_regs *regs)
{
	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
	snd_usb_substream_t *subs = ctx->subs;
	snd_pcm_substream_t *substream = ctx->subs->pcm_substream;
	int err = 0;

	if ((subs->running && subs->ops.retire_sync(subs, substream->runtime, urb)) ||
	    ! subs->running || /* can be stopped during retire callback */
	    (err = subs->ops.prepare_sync(subs, substream->runtime, urb)) < 0 ||
	    (err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
		clear_bit(ctx->index + 16, &subs->active_mask);
		if (err < 0) {
			snd_printd(KERN_ERR "cannot submit sync urb (err = %d)\n", err);
			snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
		}
	}
}


/* get the physical page pointer at the given offset */
static struct page *snd_pcm_get_vmalloc_page(snd_pcm_substream_t *subs,
					     unsigned long offset)
{
	void *pageptr = subs->runtime->dma_area + offset;
	return vmalloc_to_page(pageptr);
}

/* allocate virtual buffer; may be called more than once */
static int snd_pcm_alloc_vmalloc_buffer(snd_pcm_substream_t *subs, size_t size)
{
	snd_pcm_runtime_t *runtime = subs->runtime;
	if (runtime->dma_area) {
		if (runtime->dma_bytes >= size)
			return 0; /* already large enough */
		vfree_nocheck(runtime->dma_area);
	}
	runtime->dma_area = vmalloc_nocheck(size);
	if (! runtime->dma_area)
		return -ENOMEM;
	runtime->dma_bytes = size;
	return 0;
}

/* free virtual buffer; may be called more than once */
static int snd_pcm_free_vmalloc_buffer(snd_pcm_substream_t *subs)
{
	snd_pcm_runtime_t *runtime = subs->runtime;
	if (runtime->dma_area) {
		vfree_nocheck(runtime->dma_area);
		runtime->dma_area = NULL;
	}
	return 0;
}


/*
 * unlink active urbs.
 */
static int deactivate_urbs(snd_usb_substream_t *subs, int force, int can_sleep)
{
	unsigned int i;
	int async;

	subs->running = 0;

	if (!force && subs->stream->chip->shutdown) /* to be sure... */
		return -EBADFD;

	async = !can_sleep && async_unlink;

	if (! async && in_interrupt())
		return 0;

	for (i = 0; i < subs->nurbs; i++) {
		if (test_bit(i, &subs->active_mask)) {
			if (! test_and_set_bit(i, &subs->unlink_mask)) {
				struct urb *u = subs->dataurb[i].urb;
				if (async)
					usb_unlink_urb(u);
				else
					usb_kill_urb(u);
			}
		}
	}
	if (subs->syncpipe) {
		for (i = 0; i < SYNC_URBS; i++) {
			if (test_bit(i+16, &subs->active_mask)) {
 				if (! test_and_set_bit(i+16, &subs->unlink_mask)) {
					struct urb *u = subs->syncurb[i].urb;
					if (async)
						usb_unlink_urb(u);
					else
						usb_kill_urb(u);
				}
			}
		}
	}
	return 0;
}


/*
 * set up and start data/sync urbs
 */
static int start_urbs(snd_usb_substream_t *subs, snd_pcm_runtime_t *runtime)
{
	unsigned int i;
	int err;

	if (subs->stream->chip->shutdown)
		return -EBADFD;

	for (i = 0; i < subs->nurbs; i++) {
		snd_assert(subs->dataurb[i].urb, return -EINVAL);
		if (subs->ops.prepare(subs, runtime, subs->dataurb[i].urb) < 0) {
			snd_printk(KERN_ERR "cannot prepare datapipe for urb %d\n", i);
			goto __error;
		}
	}
	if (subs->syncpipe) {
		for (i = 0; i < SYNC_URBS; i++) {
			snd_assert(subs->syncurb[i].urb, return -EINVAL);
			if (subs->ops.prepare_sync(subs, runtime, subs->syncurb[i].urb) < 0) {
				snd_printk(KERN_ERR "cannot prepare syncpipe for urb %d\n", i);
				goto __error;
			}
		}
	}

	subs->active_mask = 0;
	subs->unlink_mask = 0;
	subs->running = 1;
	for (i = 0; i < subs->nurbs; i++) {
		if ((err = usb_submit_urb(subs->dataurb[i].urb, GFP_ATOMIC)) < 0) {
			snd_printk(KERN_ERR "cannot submit datapipe for urb %d, err = %d\n", i, err);
			goto __error;
		}
		set_bit(i, &subs->active_mask);
	}
	if (subs->syncpipe) {
		for (i = 0; i < SYNC_URBS; i++) {
			if ((err = usb_submit_urb(subs->syncurb[i].urb, GFP_ATOMIC)) < 0) {
				snd_printk(KERN_ERR "cannot submit syncpipe for urb %d, err = %d\n", i, err);
				goto __error;
			}
			set_bit(i + 16, &subs->active_mask);
		}
	}
	return 0;

 __error:
	// snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN);
	deactivate_urbs(subs, 0, 0);
	return -EPIPE;
}


/*
 *  wait until all urbs are processed.
 */
static int wait_clear_urbs(snd_usb_substream_t *subs)
{
	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
	unsigned int i;
	int alive;

	do {
		alive = 0;
		for (i = 0; i < subs->nurbs; i++) {
			if (test_bit(i, &subs->active_mask))
				alive++;
		}
		if (subs->syncpipe) {
			for (i = 0; i < SYNC_URBS; i++) {
				if (test_bit(i + 16, &subs->active_mask))
					alive++;
			}
		}
		if (! alive)
			break;
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(1);
	} while (time_before(jiffies, end_time));
	if (alive)
		snd_printk(KERN_ERR "timeout: still %d active urbs..\n", alive);
	return 0;
}


/*
 * return the current pcm pointer.  just return the hwptr_done value.
 */
static snd_pcm_uframes_t snd_usb_pcm_pointer(snd_pcm_substream_t *substream)
{
	snd_usb_substream_t *subs;
	snd_pcm_uframes_t hwptr_done;
	
	subs = (snd_usb_substream_t *)substream->runtime->private_data;
	spin_lock(&subs->lock);
	hwptr_done = subs->hwptr_done;
	spin_unlock(&subs->lock);
	return hwptr_done;
}


/*
 * start/stop substream
 */
static int snd_usb_pcm_trigger(snd_pcm_substream_t *substream, int cmd)
{
	snd_usb_substream_t *subs = (snd_usb_substream_t *)substream->runtime->private_data;
	int err;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		err = start_urbs(subs, substream->runtime);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
		err = deactivate_urbs(subs, 0, 0);
		break;
	default:
		err = -EINVAL;
		break;
	}
	return err < 0 ? err : 0;
}


/*
 * release a urb data
 */
static void release_urb_ctx(snd_urb_ctx_t *u)
{
	if (u->urb) {
		if (u->buffer_size)
			usb_buffer_free(u->subs->dev, u->buffer_size,
					u->urb->transfer_buffer,
					u->urb->transfer_dma);
		usb_free_urb(u->urb);
		u->urb = NULL;
	}
}

/*
 * release a substream
 */
static void release_substream_urbs(snd_usb_substream_t *subs, int force)
{
	int i;

	/* stop urbs (to be sure) */
	deactivate_urbs(subs, force, 1);
	wait_clear_urbs(subs);

	for (i = 0; i < MAX_URBS; i++)
		release_urb_ctx(&subs->dataurb[i]);
	for (i = 0; i < SYNC_URBS; i++)
		release_urb_ctx(&subs->syncurb[i]);
	usb_buffer_free(subs->dev, SYNC_URBS * 4,
			subs->syncbuf, subs->sync_dma);
	subs->syncbuf = NULL;
	subs->nurbs = 0;
}

/*
 * initialize a substream for plaback/capture
 */
static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_bytes,
			       unsigned int rate, unsigned int frame_bits)
{
	unsigned int maxsize, n, i;
	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
	unsigned int npacks[MAX_URBS], urb_packs, total_packs, packs_per_ms;

	/* calculate the frequency in 16.16 format */
	if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
		subs->freqn = get_usb_full_speed_rate(rate);
	else
		subs->freqn = get_usb_high_speed_rate(rate);
	subs->freqm = subs->freqn;
	/* calculate max. frequency */
	if (subs->maxpacksize) {
		/* whatever fits into a max. size packet */
		maxsize = subs->maxpacksize;
		subs->freqmax = (maxsize / (frame_bits >> 3))
				<< (16 - subs->datainterval);
	} else {
		/* no max. packet size: just take 25% higher than nominal */
		subs->freqmax = subs->freqn + (subs->freqn >> 2);
		maxsize = ((subs->freqmax + 0xffff) * (frame_bits >> 3))
				>> (16 - subs->datainterval);
	}
	subs->phase = 0;

	if (subs->fill_max)
		subs->curpacksize = subs->maxpacksize;
	else
		subs->curpacksize = maxsize;

	if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH)
		packs_per_ms = 8 >> subs->datainterval;
	else
		packs_per_ms = 1;
	subs->packs_per_ms = packs_per_ms;

	if (is_playback) {
		urb_packs = nrpacks;
		urb_packs = max(urb_packs, (unsigned int)MIN_PACKS_URB);
		urb_packs = min(urb_packs, (unsigned int)MAX_PACKS);
	} else
		urb_packs = 1;
	urb_packs *= packs_per_ms;

	/* decide how many packets to be used */
	if (is_playback) {
		unsigned int minsize;
		/* determine how small a packet can be */
		minsize = (subs->freqn >> (16 - subs->datainterval))
			  * (frame_bits >> 3);
		/* with sync from device, assume it can be 12% lower */
		if (subs->syncpipe)
			minsize -= minsize >> 3;
		minsize = max(minsize, 1u);
		total_packs = (period_bytes + minsize - 1) / minsize;
		/* round up to multiple of packs_per_ms */
		total_packs = (total_packs + packs_per_ms - 1)
				& ~(packs_per_ms - 1);
		/* we need at least two URBs for queueing */
		if (total_packs < 2 * MIN_PACKS_URB * packs_per_ms)
			total_packs = 2 * MIN_PACKS_URB * packs_per_ms;
	} else {
		total_packs = MAX_URBS * urb_packs;
	}
	subs->nurbs = (total_packs + urb_packs - 1) / urb_packs;
	if (subs->nurbs > MAX_URBS) {
		/* too much... */
		subs->nurbs = MAX_URBS;
		total_packs = MAX_URBS * urb_packs;
	}
	n = total_packs;
	for (i = 0; i < subs->nurbs; i++) {
		npacks[i] = n > urb_packs ? urb_packs : n;
		n -= urb_packs;
	}
	if (subs->nurbs <= 1) {
		/* too little - we need at least two packets
		 * to ensure contiguous playback/capture
		 */
		subs->nurbs = 2;
		npacks[0] = (total_packs + 1) / 2;
		npacks[1] = total_packs - npacks[0];
	} else if (npacks[subs->nurbs-1] < MIN_PACKS_URB * packs_per_ms) {
		/* the last packet is too small.. */
		if (subs->nurbs > 2) {
			/* merge to the first one */
			npacks[0] += npacks[subs->nurbs - 1];
			subs->nurbs--;
		} else {
			/* divide to two */
			subs->nurbs = 2;
			npacks[0] = (total_packs + 1) / 2;
			npacks[1] = total_packs - npacks[0];
		}
	}

	/* allocate and initialize data urbs */
	for (i = 0; i < subs->nurbs; i++) {
		snd_urb_ctx_t *u = &subs->dataurb[i];
		u->index = i;
		u->subs = subs;
		u->packets = npacks[i];
		u->buffer_size = maxsize * u->packets;
		if (subs->fmt_type == USB_FORMAT_TYPE_II)
			u->packets++; /* for transfer delimiter */
		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
		if (! u->urb)
			goto out_of_memory;
		u->urb->transfer_buffer =
			usb_buffer_alloc(subs->dev, u->buffer_size, GFP_KERNEL,
					 &u->urb->transfer_dma);
		if (! u->urb->transfer_buffer)
			goto out_of_memory;
		u->urb->pipe = subs->datapipe;
		u->urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
		u->urb->interval = 1 << subs->datainterval;
		u->urb->context = u;
		u->urb->complete = snd_usb_complete_callback(snd_complete_urb);
	}

	if (subs->syncpipe) {
		/* allocate and initialize sync urbs */
		subs->syncbuf = usb_buffer_alloc(subs->dev, SYNC_URBS * 4,
						 GFP_KERNEL, &subs->sync_dma);
		if (! subs->syncbuf)
			goto out_of_memory;
		for (i = 0; i < SYNC_URBS; i++) {
			snd_urb_ctx_t *u = &subs->syncurb[i];
			u->index = i;
			u->subs = subs;
			u->packets = 1;
			u->urb = usb_alloc_urb(1, GFP_KERNEL);
			if (! u->urb)
				goto out_of_memory;
			u->urb->transfer_buffer = subs->syncbuf + i * 4;
			u->urb->transfer_dma = subs->sync_dma + i * 4;
			u->urb->transfer_buffer_length = 4;
			u->urb->pipe = subs->syncpipe;
			u->urb->transfer_flags = URB_ISO_ASAP |
						 URB_NO_TRANSFER_DMA_MAP;
			u->urb->number_of_packets = 1;
			u->urb->interval = 1 << subs->syncinterval;
			u->urb->context = u;
			u->urb->complete = snd_usb_complete_callback(snd_complete_sync_urb);
		}
	}
	return 0;

out_of_memory:
	release_substream_urbs(subs, 0);
	return -ENOMEM;
}


/*
 * find a matching audio format
 */
static struct audioformat *find_format(snd_usb_substream_t *subs, unsigned int format,
				       unsigned int rate, unsigned int channels)
{
	struct list_head *p;
	struct audioformat *found = NULL;
	int cur_attr = 0, attr;

	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (fp->format != format || fp->channels != channels)
			continue;
		if (rate < fp->rate_min || rate > fp->rate_max)
			continue;
		if (! (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
			unsigned int i;
			for (i = 0; i < fp->nr_rates; i++)
				if (fp->rate_table[i] == rate)
					break;
			if (i >= fp->nr_rates)
				continue;
		}
		attr = fp->ep_attr & EP_ATTR_MASK;
		if (! found) {
			found = fp;
			cur_attr = attr;
			continue;
		}
		/* avoid async out and adaptive in if the other method
		 * supports the same format.
		 * this is a workaround for the case like
		 * M-audio audiophile USB.
		 */
		if (attr != cur_attr) {
			if ((attr == EP_ATTR_ASYNC &&
			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
			    (attr == EP_ATTR_ADAPTIVE &&
			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
				continue;
			if ((cur_attr == EP_ATTR_ASYNC &&
			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
			    (cur_attr == EP_ATTR_ADAPTIVE &&
			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
				found = fp;
				cur_attr = attr;
				continue;
			}
		}
		/* find the format with the largest max. packet size */
		if (fp->maxpacksize > found->maxpacksize) {
			found = fp;
			cur_attr = attr;
		}
	}
	return found;
}


/*
 * initialize the picth control and sample rate
 */
static int init_usb_pitch(struct usb_device *dev, int iface,
			  struct usb_host_interface *alts,
			  struct audioformat *fmt)
{
	unsigned int ep;
	unsigned char data[1];
	int err;

	ep = get_endpoint(alts, 0)->bEndpointAddress;
	/* if endpoint has pitch control, enable it */
	if (fmt->attributes & EP_CS_ATTR_PITCH_CONTROL) {
		data[0] = 1;
		if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), SET_CUR,
					   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
					   PITCH_CONTROL << 8, ep, data, 1, 1000)) < 0) {
			snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH\n",
				   dev->devnum, iface, ep);
			return err;
		}
	}
	return 0;
}

static int init_usb_sample_rate(struct usb_device *dev, int iface,
				struct usb_host_interface *alts,
				struct audioformat *fmt, int rate)
{
	unsigned int ep;
	unsigned char data[3];
	int err;

	ep = get_endpoint(alts, 0)->bEndpointAddress;
	/* if endpoint has sampling rate control, set it */
	if (fmt->attributes & EP_CS_ATTR_SAMPLE_RATE) {
		int crate;
		data[0] = rate;
		data[1] = rate >> 8;
		data[2] = rate >> 16;
		if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), SET_CUR,
					   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
					   SAMPLING_FREQ_CONTROL << 8, ep, data, 3, 1000)) < 0) {
			snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d to ep 0x%x\n",
				   dev->devnum, iface, fmt->altsetting, rate, ep);
			return err;
		}
		if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), GET_CUR,
					   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_IN,
					   SAMPLING_FREQ_CONTROL << 8, ep, data, 3, 1000)) < 0) {
			snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq at ep 0x%x\n",
				   dev->devnum, iface, fmt->altsetting, ep);
			return 0; /* some devices don't support reading */
		}
		crate = data[0] | (data[1] << 8) | (data[2] << 16);
		if (crate != rate) {
			snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
			// runtime->rate = crate;
		}
	}
	return 0;
}

/*
 * find a matching format and set up the interface
 */
static int set_format(snd_usb_substream_t *subs, struct audioformat *fmt)
{
	struct usb_device *dev = subs->dev;
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	struct usb_interface *iface;
	unsigned int ep, attr;
	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
	int err;

	iface = usb_ifnum_to_if(dev, fmt->iface);
	snd_assert(iface, return -EINVAL);
	alts = &iface->altsetting[fmt->altset_idx];
	altsd = get_iface_desc(alts);
	snd_assert(altsd->bAlternateSetting == fmt->altsetting, return -EINVAL);

	if (fmt == subs->cur_audiofmt)
		return 0;

	/* close the old interface */
	if (subs->interface >= 0 && subs->interface != fmt->iface) {
		usb_set_interface(subs->dev, subs->interface, 0);
		subs->interface = -1;
		subs->format = 0;
	}

	/* set interface */
	if (subs->interface != fmt->iface || subs->format != fmt->altset_idx) {
		if (usb_set_interface(dev, fmt->iface, fmt->altsetting) < 0) {
			snd_printk(KERN_ERR "%d:%d:%d: usb_set_interface failed\n",
				   dev->devnum, fmt->iface, fmt->altsetting);
			return -EIO;
		}
		snd_printdd(KERN_INFO "setting usb interface %d:%d\n", fmt->iface, fmt->altsetting);
		subs->interface = fmt->iface;
		subs->format = fmt->altset_idx;
	}

	/* create a data pipe */
	ep = fmt->endpoint & USB_ENDPOINT_NUMBER_MASK;
	if (is_playback)
		subs->datapipe = usb_sndisocpipe(dev, ep);
	else
		subs->datapipe = usb_rcvisocpipe(dev, ep);
	if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH &&
	    get_endpoint(alts, 0)->bInterval >= 1 &&
	    get_endpoint(alts, 0)->bInterval <= 4)
		subs->datainterval = get_endpoint(alts, 0)->bInterval - 1;
	else
		subs->datainterval = 0;
	subs->syncpipe = subs->syncinterval = 0;
	subs->maxpacksize = fmt->maxpacksize;
	subs->fill_max = 0;

	/* we need a sync pipe in async OUT or adaptive IN mode */
	/* check the number of EP, since some devices have broken
	 * descriptors which fool us.  if it has only one EP,
	 * assume it as adaptive-out or sync-in.
	 */
	attr = fmt->ep_attr & EP_ATTR_MASK;
	if (((is_playback && attr == EP_ATTR_ASYNC) ||
	     (! is_playback && attr == EP_ATTR_ADAPTIVE)) &&
	    altsd->bNumEndpoints >= 2) {
		/* check sync-pipe endpoint */
		/* ... and check descriptor size before accessing bSynchAddress
		   because there is a version of the SB Audigy 2 NX firmware lacking
		   the audio fields in the endpoint descriptors */
		if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 ||
		    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
		     get_endpoint(alts, 1)->bSynchAddress != 0)) {
			snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
				   dev->devnum, fmt->iface, fmt->altsetting);
			return -EINVAL;
		}
		ep = get_endpoint(alts, 1)->bEndpointAddress;
		if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
		    (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
		     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
			snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
				   dev->devnum, fmt->iface, fmt->altsetting);
			return -EINVAL;
		}
		ep &= USB_ENDPOINT_NUMBER_MASK;
		if (is_playback)
			subs->syncpipe = usb_rcvisocpipe(dev, ep);
		else
			subs->syncpipe = usb_sndisocpipe(dev, ep);
		if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
		    get_endpoint(alts, 1)->bRefresh >= 1 &&
		    get_endpoint(alts, 1)->bRefresh <= 9)
			subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
		else if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
			subs->syncinterval = 1;
		else if (get_endpoint(alts, 1)->bInterval >= 1 &&
			 get_endpoint(alts, 1)->bInterval <= 16)
			subs->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
		else
			subs->syncinterval = 3;
	}

	/* always fill max packet size */
	if (fmt->attributes & EP_CS_ATTR_FILL_MAX)
		subs->fill_max = 1;

	if ((err = init_usb_pitch(dev, subs->interface, alts, fmt)) < 0)
		return err;

	subs->cur_audiofmt = fmt;

#if 0
	printk("setting done: format = %d, rate = %d, channels = %d\n",
	       fmt->format, fmt->rate, fmt->channels);
	printk("  datapipe = 0x%0x, syncpipe = 0x%0x\n",
	       subs->datapipe, subs->syncpipe);
#endif

	return 0;
}

/*
 * hw_params callback
 *
 * allocate a buffer and set the given audio format.
 *
 * so far we use a physically linear buffer although packetize transfer
 * doesn't need a continuous area.
 * if sg buffer is supported on the later version of alsa, we'll follow
 * that.
 */
static int snd_usb_hw_params(snd_pcm_substream_t *substream,
			     snd_pcm_hw_params_t *hw_params)
{
	snd_usb_substream_t *subs = (snd_usb_substream_t *)substream->runtime->private_data;
	struct audioformat *fmt;
	unsigned int channels, rate, format;
	int ret, changed;

	ret = snd_pcm_alloc_vmalloc_buffer(substream,
					   params_buffer_bytes(hw_params));
	if (ret < 0)
		return ret;

	format = params_format(hw_params);
	rate = params_rate(hw_params);
	channels = params_channels(hw_params);
	fmt = find_format(subs, format, rate, channels);
	if (! fmt) {
		snd_printd(KERN_DEBUG "cannot set format: format = %s, rate = %d, channels = %d\n",
			   snd_pcm_format_name(format), rate, channels);
		return -EINVAL;
	}

	changed = subs->cur_audiofmt != fmt ||
		subs->period_bytes != params_period_bytes(hw_params) ||
		subs->cur_rate != rate;
	if ((ret = set_format(subs, fmt)) < 0)
		return ret;

	if (subs->cur_rate != rate) {
		struct usb_host_interface *alts;
		struct usb_interface *iface;
		iface = usb_ifnum_to_if(subs->dev, fmt->iface);
		alts = &iface->altsetting[fmt->altset_idx];
		ret = init_usb_sample_rate(subs->dev, subs->interface, alts, fmt, rate);
		if (ret < 0)
			return ret;
		subs->cur_rate = rate;
	}

	if (changed) {
		/* format changed */
		release_substream_urbs(subs, 0);
		/* influenced: period_bytes, channels, rate, format, */
		ret = init_substream_urbs(subs, params_period_bytes(hw_params),
					  params_rate(hw_params),
					  snd_pcm_format_physical_width(params_format(hw_params)) * params_channels(hw_params));
	}

	return ret;
}

/*
 * hw_free callback
 *
 * reset the audio format and release the buffer
 */
static int snd_usb_hw_free(snd_pcm_substream_t *substream)
{
	snd_usb_substream_t *subs = (snd_usb_substream_t *)substream->runtime->private_data;

	subs->cur_audiofmt = NULL;
	subs->cur_rate = 0;
	subs->period_bytes = 0;
	release_substream_urbs(subs, 0);
	return snd_pcm_free_vmalloc_buffer(substream);
}

/*
 * prepare callback
 *
 * only a few subtle things...
 */
static int snd_usb_pcm_prepare(snd_pcm_substream_t *substream)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	snd_usb_substream_t *subs = (snd_usb_substream_t *)runtime->private_data;

	if (! subs->cur_audiofmt) {
		snd_printk(KERN_ERR "usbaudio: no format is specified!\n");
		return -ENXIO;
	}

	/* some unit conversions in runtime */
	subs->maxframesize = bytes_to_frames(runtime, subs->maxpacksize);
	subs->curframesize = bytes_to_frames(runtime, subs->curpacksize);

	/* reset the pointer */
	subs->hwptr_done = 0;
	subs->transfer_done = 0;
	subs->phase = 0;

	/* clear urbs (to be sure) */
	deactivate_urbs(subs, 0, 1);
	wait_clear_urbs(subs);

	return 0;
}

static snd_pcm_hardware_t snd_usb_playback =
{
	.info =			SNDRV_PCM_INFO_MMAP |
				SNDRV_PCM_INFO_MMAP_VALID |
				SNDRV_PCM_INFO_BATCH |
				SNDRV_PCM_INFO_INTERLEAVED |
				SNDRV_PCM_INFO_BLOCK_TRANSFER,
	.buffer_bytes_max =	1024 * 1024,
	.period_bytes_min =	64,
	.period_bytes_max =	512 * 1024,
	.periods_min =		2,
	.periods_max =		1024,
};

static snd_pcm_hardware_t snd_usb_capture =
{
	.info =			SNDRV_PCM_INFO_MMAP |
				SNDRV_PCM_INFO_MMAP_VALID |
				SNDRV_PCM_INFO_BATCH |
				SNDRV_PCM_INFO_INTERLEAVED |
				SNDRV_PCM_INFO_BLOCK_TRANSFER,
	.buffer_bytes_max =	1024 * 1024,
	.period_bytes_min =	64,
	.period_bytes_max =	512 * 1024,
	.periods_min =		2,
	.periods_max =		1024,
};

/*
 * h/w constraints
 */

#ifdef HW_CONST_DEBUG
#define hwc_debug(fmt, args...) printk(KERN_DEBUG fmt, ##args)
#else
#define hwc_debug(fmt, args...) /**/
#endif

static int hw_check_valid_format(snd_pcm_hw_params_t *params, struct audioformat *fp)
{
	snd_interval_t *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
	snd_interval_t *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	snd_mask_t *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);

	/* check the format */
	if (! snd_mask_test(fmts, fp->format)) {
		hwc_debug("   > check: no supported format %d\n", fp->format);
		return 0;
	}
	/* check the channels */
	if (fp->channels < ct->min || fp->channels > ct->max) {
		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
		return 0;
	}
	/* check the rate is within the range */
	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
		return 0;
	}
	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
		return 0;
	}
	return 1;
}

static int hw_rule_rate(snd_pcm_hw_params_t *params,
			snd_pcm_hw_rule_t *rule)
{
	snd_usb_substream_t *subs = rule->private;
	struct list_head *p;
	snd_interval_t *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
	unsigned int rmin, rmax;
	int changed;

	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
	changed = 0;
	rmin = rmax = 0;
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (! hw_check_valid_format(params, fp))
			continue;
		if (changed++) {
			if (rmin > fp->rate_min)
				rmin = fp->rate_min;
			if (rmax < fp->rate_max)
				rmax = fp->rate_max;
		} else {
			rmin = fp->rate_min;
			rmax = fp->rate_max;
		}
	}

	if (! changed) {
		hwc_debug("  --> get empty\n");
		it->empty = 1;
		return -EINVAL;
	}

	changed = 0;
	if (it->min < rmin) {
		it->min = rmin;
		it->openmin = 0;
		changed = 1;
	}
	if (it->max > rmax) {
		it->max = rmax;
		it->openmax = 0;
		changed = 1;
	}
	if (snd_interval_checkempty(it)) {
		it->empty = 1;
		return -EINVAL;
	}
	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
	return changed;
}


static int hw_rule_channels(snd_pcm_hw_params_t *params,
			    snd_pcm_hw_rule_t *rule)
{
	snd_usb_substream_t *subs = rule->private;
	struct list_head *p;
	snd_interval_t *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	unsigned int rmin, rmax;
	int changed;

	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
	changed = 0;
	rmin = rmax = 0;
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (! hw_check_valid_format(params, fp))
			continue;
		if (changed++) {
			if (rmin > fp->channels)
				rmin = fp->channels;
			if (rmax < fp->channels)
				rmax = fp->channels;
		} else {
			rmin = fp->channels;
			rmax = fp->channels;
		}
	}

	if (! changed) {
		hwc_debug("  --> get empty\n");
		it->empty = 1;
		return -EINVAL;
	}

	changed = 0;
	if (it->min < rmin) {
		it->min = rmin;
		it->openmin = 0;
		changed = 1;
	}
	if (it->max > rmax) {
		it->max = rmax;
		it->openmax = 0;
		changed = 1;
	}
	if (snd_interval_checkempty(it)) {
		it->empty = 1;
		return -EINVAL;
	}
	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
	return changed;
}

static int hw_rule_format(snd_pcm_hw_params_t *params,
			  snd_pcm_hw_rule_t *rule)
{
	snd_usb_substream_t *subs = rule->private;
	struct list_head *p;
	snd_mask_t *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
	u64 fbits;
	u32 oldbits[2];
	int changed;

	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
	fbits = 0;
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (! hw_check_valid_format(params, fp))
			continue;
		fbits |= (1ULL << fp->format);
	}

	oldbits[0] = fmt->bits[0];
	oldbits[1] = fmt->bits[1];
	fmt->bits[0] &= (u32)fbits;
	fmt->bits[1] &= (u32)(fbits >> 32);
	if (! fmt->bits[0] && ! fmt->bits[1]) {
		hwc_debug("  --> get empty\n");
		return -EINVAL;
	}
	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
	return changed;
}

#define MAX_MASK	64

/*
 * check whether the registered audio formats need special hw-constraints
 */
static int check_hw_params_convention(snd_usb_substream_t *subs)
{
	int i;
	u32 *channels;
	u32 *rates;
	u32 cmaster, rmaster;
	u32 rate_min = 0, rate_max = 0;
	struct list_head *p;
	int err = 1;

	channels = kcalloc(MAX_MASK, sizeof(u32), GFP_KERNEL);
	rates = kcalloc(MAX_MASK, sizeof(u32), GFP_KERNEL);

	list_for_each(p, &subs->fmt_list) {
		struct audioformat *f;
		f = list_entry(p, struct audioformat, list);
		/* unconventional channels? */
		if (f->channels > 32)
			goto __out;
		/* continuous rate min/max matches? */
		if (f->rates & SNDRV_PCM_RATE_CONTINUOUS) {
			if (rate_min && f->rate_min != rate_min)
				goto __out;
			if (rate_max && f->rate_max != rate_max)
				goto __out;
			rate_min = f->rate_min;
			rate_max = f->rate_max;
		}
		/* combination of continuous rates and fixed rates? */
		if (rates[f->format] & SNDRV_PCM_RATE_CONTINUOUS) {
			if (f->rates != rates[f->format])
				goto __out;
		}
		if (f->rates & SNDRV_PCM_RATE_CONTINUOUS) {
			if (rates[f->format] && rates[f->format] != f->rates)
				goto __out;
		}
		channels[f->format] |= (1 << f->channels);
		rates[f->format] |= f->rates;
	}
	/* check whether channels and rates match for all formats */
	cmaster = rmaster = 0;
	for (i = 0; i < MAX_MASK; i++) {
		if (cmaster != channels[i] && cmaster && channels[i])
			goto __out;
		if (rmaster != rates[i] && rmaster && rates[i])
			goto __out;
		if (channels[i])
			cmaster = channels[i];
		if (rates[i])
			rmaster = rates[i];
	}
	/* check whether channels match for all distinct rates */
	memset(channels, 0, MAX_MASK * sizeof(u32));
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *f;
		f = list_entry(p, struct audioformat, list);
		if (f->rates & SNDRV_PCM_RATE_CONTINUOUS)
			continue;
		for (i = 0; i < 32; i++) {
			if (f->rates & (1 << i))
				channels[i] |= (1 << f->channels);
		}
	}
	cmaster = 0;
	for (i = 0; i < 32; i++) {
		if (cmaster != channels[i] && cmaster && channels[i])
			goto __out;
		if (channels[i])
			cmaster = channels[i];
	}
	err = 0;

 __out:
	kfree(channels);
	kfree(rates);
	return err;
}


/*
 * set up the runtime hardware information.
 */

static int setup_hw_info(snd_pcm_runtime_t *runtime, snd_usb_substream_t *subs)
{
	struct list_head *p;
	int err;

	runtime->hw.formats = subs->formats;

	runtime->hw.rate_min = 0x7fffffff;
	runtime->hw.rate_max = 0;
	runtime->hw.channels_min = 256;
	runtime->hw.channels_max = 0;
	runtime->hw.rates = 0;
	/* check min/max rates and channels */
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		runtime->hw.rates |= fp->rates;
		if (runtime->hw.rate_min > fp->rate_min)
			runtime->hw.rate_min = fp->rate_min;
		if (runtime->hw.rate_max < fp->rate_max)
			runtime->hw.rate_max = fp->rate_max;
		if (runtime->hw.channels_min > fp->channels)
			runtime->hw.channels_min = fp->channels;
		if (runtime->hw.channels_max < fp->channels)
			runtime->hw.channels_max = fp->channels;
		if (fp->fmt_type == USB_FORMAT_TYPE_II && fp->frame_size > 0) {
			/* FIXME: there might be more than one audio formats... */
			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
				fp->frame_size;
		}
	}

	/* set the period time minimum 1ms */
	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
				     1000 * MIN_PACKS_URB,
				     /*(nrpacks * MAX_URBS) * 1000*/ UINT_MAX);

	if (check_hw_params_convention(subs)) {
		hwc_debug("setting extra hw constraints...\n");
		if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
					       hw_rule_rate, subs,
					       SNDRV_PCM_HW_PARAM_FORMAT,
					       SNDRV_PCM_HW_PARAM_CHANNELS,
					       -1)) < 0)
			return err;
		if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
					       hw_rule_channels, subs,
					       SNDRV_PCM_HW_PARAM_FORMAT,
					       SNDRV_PCM_HW_PARAM_RATE,
					       -1)) < 0)
			return err;
		if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
					       hw_rule_format, subs,
					       SNDRV_PCM_HW_PARAM_RATE,
					       SNDRV_PCM_HW_PARAM_CHANNELS,
					       -1)) < 0)
			return err;
	}
	return 0;
}

static int snd_usb_pcm_open(snd_pcm_substream_t *substream, int direction,
			    snd_pcm_hardware_t *hw)
{
	snd_usb_stream_t *as = snd_pcm_substream_chip(substream);
	snd_pcm_runtime_t *runtime = substream->runtime;
	snd_usb_substream_t *subs = &as->substream[direction];

	subs->interface = -1;
	subs->format = 0;
	runtime->hw = *hw;
	runtime->private_data = subs;
	subs->pcm_substream = substream;
	return setup_hw_info(runtime, subs);
}

static int snd_usb_pcm_close(snd_pcm_substream_t *substream, int direction)
{
	snd_usb_stream_t *as = snd_pcm_substream_chip(substream);
	snd_usb_substream_t *subs = &as->substream[direction];

	if (subs->interface >= 0) {
		usb_set_interface(subs->dev, subs->interface, 0);
		subs->interface = -1;
	}
	subs->pcm_substream = NULL;
	return 0;
}

static int snd_usb_playback_open(snd_pcm_substream_t *substream)
{
	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_PLAYBACK, &snd_usb_playback);
}

static int snd_usb_playback_close(snd_pcm_substream_t *substream)
{
	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_PLAYBACK);
}

static int snd_usb_capture_open(snd_pcm_substream_t *substream)
{
	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_CAPTURE, &snd_usb_capture);
}

static int snd_usb_capture_close(snd_pcm_substream_t *substream)
{
	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_CAPTURE);
}

static snd_pcm_ops_t snd_usb_playback_ops = {
	.open =		snd_usb_playback_open,
	.close =	snd_usb_playback_close,
	.ioctl =	snd_pcm_lib_ioctl,
	.hw_params =	snd_usb_hw_params,
	.hw_free =	snd_usb_hw_free,
	.prepare =	snd_usb_pcm_prepare,
	.trigger =	snd_usb_pcm_trigger,
	.pointer =	snd_usb_pcm_pointer,
	.page =		snd_pcm_get_vmalloc_page,
};

static snd_pcm_ops_t snd_usb_capture_ops = {
	.open =		snd_usb_capture_open,
	.close =	snd_usb_capture_close,
	.ioctl =	snd_pcm_lib_ioctl,
	.hw_params =	snd_usb_hw_params,
	.hw_free =	snd_usb_hw_free,
	.prepare =	snd_usb_pcm_prepare,
	.trigger =	snd_usb_pcm_trigger,
	.pointer =	snd_usb_pcm_pointer,
	.page =		snd_pcm_get_vmalloc_page,
};



/*
 * helper functions
 */

/*
 * combine bytes and get an integer value
 */
unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
{
	switch (size) {
	case 1:  return *bytes;
	case 2:  return combine_word(bytes);
	case 3:  return combine_triple(bytes);
	case 4:  return combine_quad(bytes);
	default: return 0;
	}
}

/*
 * parse descriptor buffer and return the pointer starting the given
 * descriptor type.
 */
void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
{
	u8 *p, *end, *next;

	p = descstart;
	end = p + desclen;
	for (; p < end;) {
		if (p[0] < 2)
			return NULL;
		next = p + p[0];
		if (next > end)
			return NULL;
		if (p[1] == dtype && (!after || (void *)p > after)) {
			return p;
		}
		p = next;
	}
	return NULL;
}

/*
 * find a class-specified interface descriptor with the given subtype.
 */
void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
{
	unsigned char *p = after;

	while ((p = snd_usb_find_desc(buffer, buflen, p,
				      USB_DT_CS_INTERFACE)) != NULL) {
		if (p[0] >= 3 && p[2] == dsubtype)
			return p;
	}
	return NULL;
}

/*
 * Wrapper for usb_control_msg().
 * Allocates a temp buffer to prevent dmaing from/to the stack.
 */
int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
		    __u8 requesttype, __u16 value, __u16 index, void *data,
		    __u16 size, int timeout)
{
	int err;
	void *buf = NULL;

	if (size > 0) {
		buf = kmalloc(size, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;
		memcpy(buf, data, size);
	}
	err = usb_control_msg(dev, pipe, request, requesttype,
			      value, index, buf, size, timeout);
	if (size > 0) {
		memcpy(data, buf, size);
		kfree(buf);
	}
	return err;
}


/*
 * entry point for linux usb interface
 */

static int usb_audio_probe(struct usb_interface *intf,
			   const struct usb_device_id *id);
static void usb_audio_disconnect(struct usb_interface *intf);

static struct usb_device_id usb_audio_ids [] = {
#include "usbquirks.h"
    { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
      .bInterfaceClass = USB_CLASS_AUDIO,
      .bInterfaceSubClass = USB_SUBCLASS_AUDIO_CONTROL },
    { }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, usb_audio_ids);

static struct usb_driver usb_audio_driver = {
	.owner =	THIS_MODULE,
	.name =		"snd-usb-audio",
	.probe =	usb_audio_probe,
	.disconnect =	usb_audio_disconnect,
	.id_table =	usb_audio_ids,
};


/*
 * proc interface for list the supported pcm formats
 */
static void proc_dump_substream_formats(snd_usb_substream_t *subs, snd_info_buffer_t *buffer)
{
	struct list_head *p;
	static char *sync_types[4] = {
		"NONE", "ASYNC", "ADAPTIVE", "SYNC"
	};

	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		snd_iprintf(buffer, "  Interface %d\n", fp->iface);
		snd_iprintf(buffer, "    Altset %d\n", fp->altsetting);
		snd_iprintf(buffer, "    Format: %s\n", snd_pcm_format_name(fp->format));
		snd_iprintf(buffer, "    Channels: %d\n", fp->channels);
		snd_iprintf(buffer, "    Endpoint: %d %s (%s)\n",
			    fp->endpoint & USB_ENDPOINT_NUMBER_MASK,
			    fp->endpoint & USB_DIR_IN ? "IN" : "OUT",
			    sync_types[(fp->ep_attr & EP_ATTR_MASK) >> 2]);
		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS) {
			snd_iprintf(buffer, "    Rates: %d - %d (continuous)\n",
				    fp->rate_min, fp->rate_max);
		} else {
			unsigned int i;
			snd_iprintf(buffer, "    Rates: ");
			for (i = 0; i < fp->nr_rates; i++) {
				if (i > 0)
					snd_iprintf(buffer, ", ");
				snd_iprintf(buffer, "%d", fp->rate_table[i]);
			}
			snd_iprintf(buffer, "\n");
		}
		// snd_iprintf(buffer, "    Max Packet Size = %d\n", fp->maxpacksize);
		// snd_iprintf(buffer, "    EP Attribute = 0x%x\n", fp->attributes);
	}
}

static void proc_dump_substream_status(snd_usb_substream_t *subs, snd_info_buffer_t *buffer)
{
	if (subs->running) {
		unsigned int i;
		snd_iprintf(buffer, "  Status: Running\n");
		snd_iprintf(buffer, "    Interface = %d\n", subs->interface);
		snd_iprintf(buffer, "    Altset = %d\n", subs->format);
		snd_iprintf(buffer, "    URBs = %d [ ", subs->nurbs);
		for (i = 0; i < subs->nurbs; i++)
			snd_iprintf(buffer, "%d ", subs->dataurb[i].packets);
		snd_iprintf(buffer, "]\n");
		snd_iprintf(buffer, "    Packet Size = %d\n", subs->curpacksize);
		snd_iprintf(buffer, "    Momentary freq = %u Hz (%#x.%04x)\n",
			    snd_usb_get_speed(subs->dev) == USB_SPEED_FULL
			    ? get_full_speed_hz(subs->freqm)
			    : get_high_speed_hz(subs->freqm),
			    subs->freqm >> 16, subs->freqm & 0xffff);
	} else {
		snd_iprintf(buffer, "  Status: Stop\n");
	}
}

static void proc_pcm_format_read(snd_info_entry_t *entry, snd_info_buffer_t *buffer)
{
	snd_usb_stream_t *stream = entry->private_data;

	snd_iprintf(buffer, "%s : %s\n", stream->chip->card->longname, stream->pcm->name);

	if (stream->substream[SNDRV_PCM_STREAM_PLAYBACK].num_formats) {
		snd_iprintf(buffer, "\nPlayback:\n");
		proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
	}
	if (stream->substream[SNDRV_PCM_STREAM_CAPTURE].num_formats) {
		snd_iprintf(buffer, "\nCapture:\n");
		proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
	}
}

static void proc_pcm_format_add(snd_usb_stream_t *stream)
{
	snd_info_entry_t *entry;
	char name[32];
	snd_card_t *card = stream->chip->card;

	sprintf(name, "stream%d", stream->pcm_index);
	if (! snd_card_proc_new(card, name, &entry))
		snd_info_set_text_ops(entry, stream, 1024, proc_pcm_format_read);
}


/*
 * initialize the substream instance.
 */

static void init_substream(snd_usb_stream_t *as, int stream, struct audioformat *fp)
{
	snd_usb_substream_t *subs = &as->substream[stream];

	INIT_LIST_HEAD(&subs->fmt_list);
	spin_lock_init(&subs->lock);
	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
		tasklet_init(&subs->start_period_elapsed, start_period_elapsed,
			     (unsigned long)subs);

	subs->stream = as;
	subs->direction = stream;
	subs->dev = as->chip->dev;
	if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
		subs->ops = audio_urb_ops[stream];
	else
		subs->ops = audio_urb_ops_high_speed[stream];
	snd_pcm_set_ops(as->pcm, stream,
			stream == SNDRV_PCM_STREAM_PLAYBACK ?
			&snd_usb_playback_ops : &snd_usb_capture_ops);

	list_add_tail(&fp->list, &subs->fmt_list);
	subs->formats |= 1ULL << fp->format;
	subs->endpoint = fp->endpoint;
	subs->num_formats++;
	subs->fmt_type = fp->fmt_type;
}


/*
 * free a substream
 */
static void free_substream(snd_usb_substream_t *subs)
{
	struct list_head *p, *n;

	if (! subs->num_formats)
		return; /* not initialized */
	list_for_each_safe(p, n, &subs->fmt_list) {
		struct audioformat *fp = list_entry(p, struct audioformat, list);
		kfree(fp->rate_table);
		kfree(fp);
	}
}


/*
 * free a usb stream instance
 */
static void snd_usb_audio_stream_free(snd_usb_stream_t *stream)
{
	free_substream(&stream->substream[0]);
	free_substream(&stream->substream[1]);
	list_del(&stream->list);
	kfree(stream);
}

static void snd_usb_audio_pcm_free(snd_pcm_t *pcm)
{
	snd_usb_stream_t *stream = pcm->private_data;
	if (stream) {
		stream->pcm = NULL;
		snd_usb_audio_stream_free(stream);
	}
}


/*
 * add this endpoint to the chip instance.
 * if a stream with the same endpoint already exists, append to it.
 * if not, create a new pcm stream.
 */
static int add_audio_endpoint(snd_usb_audio_t *chip, int stream, struct audioformat *fp)
{
	struct list_head *p;
	snd_usb_stream_t *as;
	snd_usb_substream_t *subs;
	snd_pcm_t *pcm;
	int err;

	list_for_each(p, &chip->pcm_list) {
		as = list_entry(p, snd_usb_stream_t, list);
		if (as->fmt_type != fp->fmt_type)
			continue;
		subs = &as->substream[stream];
		if (! subs->endpoint)
			continue;
		if (subs->endpoint == fp->endpoint) {
			list_add_tail(&fp->list, &subs->fmt_list);
			subs->num_formats++;
			subs->formats |= 1ULL << fp->format;
			return 0;
		}
	}
	/* look for an empty stream */
	list_for_each(p, &chip->pcm_list) {
		as = list_entry(p, snd_usb_stream_t, list);
		if (as->fmt_type != fp->fmt_type)
			continue;
		subs = &as->substream[stream];
		if (subs->endpoint)
			continue;
		err = snd_pcm_new_stream(as->pcm, stream, 1);
		if (err < 0)
			return err;
		init_substream(as, stream, fp);
		return 0;
	}

	/* create a new pcm */
	as = kmalloc(sizeof(*as), GFP_KERNEL);
	if (! as)
		return -ENOMEM;
	memset(as, 0, sizeof(*as));
	as->pcm_index = chip->pcm_devs;
	as->chip = chip;
	as->fmt_type = fp->fmt_type;
	err = snd_pcm_new(chip->card, "USB Audio", chip->pcm_devs,
			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 1 : 0,
			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1,
			  &pcm);
	if (err < 0) {
		kfree(as);
		return err;
	}
	as->pcm = pcm;
	pcm->private_data = as;
	pcm->private_free = snd_usb_audio_pcm_free;
	pcm->info_flags = 0;
	if (chip->pcm_devs > 0)
		sprintf(pcm->name, "USB Audio #%d", chip->pcm_devs);
	else
		strcpy(pcm->name, "USB Audio");

	init_substream(as, stream, fp);

	list_add(&as->list, &chip->pcm_list);
	chip->pcm_devs++;

	proc_pcm_format_add(as);

	return 0;
}


/*
 * check if the device uses big-endian samples
 */
static int is_big_endian_format(snd_usb_audio_t *chip, struct audioformat *fp)
{
	switch (chip->usb_id) {
	case USB_ID(0x0763, 0x2001): /* M-Audio Quattro: captured data only */
		if (fp->endpoint & USB_DIR_IN)
			return 1;
		break;
	case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
		return 1;
	}
	return 0;
}

/*
 * parse the audio format type I descriptor
 * and returns the corresponding pcm format
 *
 * @dev: usb device
 * @fp: audioformat record
 * @format: the format tag (wFormatTag)
 * @fmt: the format type descriptor
 */
static int parse_audio_format_i_type(snd_usb_audio_t *chip, struct audioformat *fp,
				     int format, unsigned char *fmt)
{
	int pcm_format;
	int sample_width, sample_bytes;

	/* FIXME: correct endianess and sign? */
	pcm_format = -1;
	sample_width = fmt[6];
	sample_bytes = fmt[5];
	switch (format) {
	case 0: /* some devices don't define this correctly... */
		snd_printdd(KERN_INFO "%d:%u:%d : format type 0 is detected, processed as PCM\n",
			    chip->dev->devnum, fp->iface, fp->altsetting);
		/* fall-through */
	case USB_AUDIO_FORMAT_PCM:
		if (sample_width > sample_bytes * 8) {
			snd_printk(KERN_INFO "%d:%u:%d : sample bitwidth %d in over sample bytes %d\n",
				   chip->dev->devnum, fp->iface, fp->altsetting,
				   sample_width, sample_bytes);
		}
		/* check the format byte size */
		switch (fmt[5]) {
		case 1:
			pcm_format = SNDRV_PCM_FORMAT_S8;
			break;
		case 2:
			if (is_big_endian_format(chip, fp))
				pcm_format = SNDRV_PCM_FORMAT_S16_BE; /* grrr, big endian!! */
			else
				pcm_format = SNDRV_PCM_FORMAT_S16_LE;
			break;
		case 3:
			if (is_big_endian_format(chip, fp))
				pcm_format = SNDRV_PCM_FORMAT_S24_3BE; /* grrr, big endian!! */
			else
				pcm_format = SNDRV_PCM_FORMAT_S24_3LE;
			break;
		case 4:
			pcm_format = SNDRV_PCM_FORMAT_S32_LE;
			break;
		default:
			snd_printk(KERN_INFO "%d:%u:%d : unsupported sample bitwidth %d in %d bytes\n",
				   chip->dev->devnum, fp->iface,
				   fp->altsetting, sample_width, sample_bytes);
			break;
		}
		break;
	case USB_AUDIO_FORMAT_PCM8:
		/* Dallas DS4201 workaround */
		if (chip->usb_id == USB_ID(0x04fa, 0x4201))
			pcm_format = SNDRV_PCM_FORMAT_S8;
		else
			pcm_format = SNDRV_PCM_FORMAT_U8;
		break;
	case USB_AUDIO_FORMAT_IEEE_FLOAT:
		pcm_format = SNDRV_PCM_FORMAT_FLOAT_LE;
		break;
	case USB_AUDIO_FORMAT_ALAW:
		pcm_format = SNDRV_PCM_FORMAT_A_LAW;
		break;
	case USB_AUDIO_FORMAT_MU_LAW:
		pcm_format = SNDRV_PCM_FORMAT_MU_LAW;
		break;
	default:
		snd_printk(KERN_INFO "%d:%u:%d : unsupported format type %d\n",
			   chip->dev->devnum, fp->iface, fp->altsetting, format);
		break;
	}
	return pcm_format;
}


/*
 * parse the format descriptor and stores the possible sample rates
 * on the audioformat table.
 *
 * @dev: usb device
 * @fp: audioformat record
 * @fmt: the format descriptor
 * @offset: the start offset of descriptor pointing the rate type
 *          (7 for type I and II, 8 for type II)
 */
static int parse_audio_format_rates(snd_usb_audio_t *chip, struct audioformat *fp,
				    unsigned char *fmt, int offset)
{
	int nr_rates = fmt[offset];
	if (fmt[0] < offset + 1 + 3 * (nr_rates ? nr_rates : 2)) {
		snd_printk(KERN_ERR "%d:%u:%d : invalid FORMAT_TYPE desc\n",
				   chip->dev->devnum, fp->iface, fp->altsetting);
		return -1;
	}

	if (nr_rates) {
		/*
		 * build the rate table and bitmap flags
		 */
		int r, idx, c;
		/* this table corresponds to the SNDRV_PCM_RATE_XXX bit */
		static unsigned int conv_rates[] = {
			5512, 8000, 11025, 16000, 22050, 32000, 44100, 48000,
			64000, 88200, 96000, 176400, 192000
		};
		fp->rate_table = kmalloc(sizeof(int) * nr_rates, GFP_KERNEL);
		if (fp->rate_table == NULL) {
			snd_printk(KERN_ERR "cannot malloc\n");
			return -1;
		}

		fp->nr_rates = nr_rates;
		fp->rate_min = fp->rate_max = combine_triple(&fmt[8]);
		for (r = 0, idx = offset + 1; r < nr_rates; r++, idx += 3) {
			unsigned int rate = fp->rate_table[r] = combine_triple(&fmt[idx]);
			if (rate < fp->rate_min)
				fp->rate_min = rate;
			else if (rate > fp->rate_max)
				fp->rate_max = rate;
			for (c = 0; c < (int)ARRAY_SIZE(conv_rates); c++) {
				if (rate == conv_rates[c]) {
					fp->rates |= (1 << c);
					break;
				}
			}
		}
	} else {
		/* continuous rates */
		fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
		fp->rate_min = combine_triple(&fmt[offset + 1]);
		fp->rate_max = combine_triple(&fmt[offset + 4]);
	}
	return 0;
}

/*
 * parse the format type I and III descriptors
 */
static int parse_audio_format_i(snd_usb_audio_t *chip, struct audioformat *fp,
				int format, unsigned char *fmt)
{
	int pcm_format;

	if (fmt[3] == USB_FORMAT_TYPE_III) {
		/* FIXME: the format type is really IECxxx
		 *        but we give normal PCM format to get the existing
		 *        apps working...
		 */
		pcm_format = SNDRV_PCM_FORMAT_S16_LE;
	} else {
		pcm_format = parse_audio_format_i_type(chip, fp, format, fmt);
		if (pcm_format < 0)
			return -1;
	}
	fp->format = pcm_format;
	fp->channels = fmt[4];
	if (fp->channels < 1) {
		snd_printk(KERN_ERR "%d:%u:%d : invalid channels %d\n",
			   chip->dev->devnum, fp->iface, fp->altsetting, fp->channels);
		return -1;
	}
	return parse_audio_format_rates(chip, fp, fmt, 7);
}

/*
 * prase the format type II descriptor
 */
static int parse_audio_format_ii(snd_usb_audio_t *chip, struct audioformat *fp,
				 int format, unsigned char *fmt)
{
	int brate, framesize;
	switch (format) {
	case USB_AUDIO_FORMAT_AC3:
		/* FIXME: there is no AC3 format defined yet */
		// fp->format = SNDRV_PCM_FORMAT_AC3;
		fp->format = SNDRV_PCM_FORMAT_U8; /* temporarily hack to receive byte streams */
		break;
	case USB_AUDIO_FORMAT_MPEG:
		fp->format = SNDRV_PCM_FORMAT_MPEG;
		break;
	default:
		snd_printd(KERN_INFO "%d:%u:%d : unknown format tag 0x%x is detected.  processed as MPEG.\n",
			   chip->dev->devnum, fp->iface, fp->altsetting, format);
		fp->format = SNDRV_PCM_FORMAT_MPEG;
		break;
	}
	fp->channels = 1;
	brate = combine_word(&fmt[4]); 	/* fmt[4,5] : wMaxBitRate (in kbps) */
	framesize = combine_word(&fmt[6]); /* fmt[6,7]: wSamplesPerFrame */
	snd_printd(KERN_INFO "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
	fp->frame_size = framesize;
	return parse_audio_format_rates(chip, fp, fmt, 8); /* fmt[8..] sample rates */
}

static int parse_audio_format(snd_usb_audio_t *chip, struct audioformat *fp,
			      int format, unsigned char *fmt, int stream)
{
	int err;

	switch (fmt[3]) {
	case USB_FORMAT_TYPE_I:
	case USB_FORMAT_TYPE_III:
		err = parse_audio_format_i(chip, fp, format, fmt);
		break;
	case USB_FORMAT_TYPE_II:
		err = parse_audio_format_ii(chip, fp, format, fmt);
		break;
	default:
		snd_printd(KERN_INFO "%d:%u:%d : format type %d is not supported yet\n",
			   chip->dev->devnum, fp->iface, fp->altsetting, fmt[3]);
		return -1;
	}
	fp->fmt_type = fmt[3];
	if (err < 0)
		return err;
#if 1
	/* FIXME: temporary hack for extigy/audigy 2 nx */
	/* extigy apparently supports sample rates other than 48k
	 * but not in ordinary way.  so we enable only 48k atm.
	 */
	if (chip->usb_id == USB_ID(0x041e, 0x3000) ||
	    chip->usb_id == USB_ID(0x041e, 0x3020)) {
		if (fmt[3] == USB_FORMAT_TYPE_I &&
		    fp->rates != SNDRV_PCM_RATE_48000 &&
		    fp->rates != SNDRV_PCM_RATE_96000)
			return -1;
	}
#endif
	return 0;
}

static int parse_audio_endpoints(snd_usb_audio_t *chip, int iface_no)
{
	struct usb_device *dev;
	struct usb_interface *iface;
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	int i, altno, err, stream;
	int format;
	struct audioformat *fp;
	unsigned char *fmt, *csep;

	dev = chip->dev;

	/* parse the interface's altsettings */
	iface = usb_ifnum_to_if(dev, iface_no);
	for (i = 0; i < iface->num_altsetting; i++) {
		alts = &iface->altsetting[i];
		altsd = get_iface_desc(alts);
		/* skip invalid one */
		if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
		     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
		    (altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIO_STREAMING &&
		     altsd->bInterfaceSubClass != USB_SUBCLASS_VENDOR_SPEC) ||
		    altsd->bNumEndpoints < 1 ||
		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == 0)
			continue;
		/* must be isochronous */
		if ((get_endpoint(alts, 0)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
		    USB_ENDPOINT_XFER_ISOC)
			continue;
		/* check direction */
		stream = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN) ?
			SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
		altno = altsd->bAlternateSetting;

		/* get audio formats */
		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, AS_GENERAL);
		if (!fmt) {
			snd_printk(KERN_ERR "%d:%u:%d : AS_GENERAL descriptor not found\n",
				   dev->devnum, iface_no, altno);
			continue;
		}

		if (fmt[0] < 7) {
			snd_printk(KERN_ERR "%d:%u:%d : invalid AS_GENERAL desc\n",
				   dev->devnum, iface_no, altno);
			continue;
		}

		format = (fmt[6] << 8) | fmt[5]; /* remember the format value */

		/* get format type */
		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL, FORMAT_TYPE);
		if (!fmt) {
			snd_printk(KERN_ERR "%d:%u:%d : no FORMAT_TYPE desc\n",
				   dev->devnum, iface_no, altno);
			continue;
		}
		if (fmt[0] < 8) {
			snd_printk(KERN_ERR "%d:%u:%d : invalid FORMAT_TYPE desc\n",
				   dev->devnum, iface_no, altno);
			continue;
		}

		csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
		/* Creamware Noah has this descriptor after the 2nd endpoint */
		if (!csep && altsd->bNumEndpoints >= 2)
			csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
		if (!csep || csep[0] < 7 || csep[2] != EP_GENERAL) {
			snd_printk(KERN_ERR "%d:%u:%d : no or invalid class specific endpoint descriptor\n",
				   dev->devnum, iface_no, altno);
			continue;
		}

		fp = kmalloc(sizeof(*fp), GFP_KERNEL);
		if (! fp) {
			snd_printk(KERN_ERR "cannot malloc\n");
			return -ENOMEM;
		}

		memset(fp, 0, sizeof(*fp));
		fp->iface = iface_no;
		fp->altsetting = altno;
		fp->altset_idx = i;
		fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
		fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
		if (snd_usb_get_speed(dev) == USB_SPEED_HIGH)
			fp->maxpacksize = (((fp->maxpacksize >> 11) & 3) + 1)
					* (fp->maxpacksize & 0x7ff);
		fp->attributes = csep[3];

		/* some quirks for attributes here */

		switch (chip->usb_id) {
		case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
			/* Optoplay sets the sample rate attribute although
			 * it seems not supporting it in fact.
			 */
			fp->attributes &= ~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 |= EP_CS_ATTR_SAMPLE_RATE;
			break;
		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 &= ~EP_ATTR_MASK;
			if (stream == SNDRV_PCM_STREAM_PLAYBACK)
				fp->ep_attr |= EP_ATTR_ADAPTIVE;
			else
				fp->ep_attr |= EP_ATTR_SYNC;
			break;
		}

		/* ok, let's parse further... */
		if (parse_audio_format(chip, fp, format, fmt, stream) < 0) {
			kfree(fp->rate_table);
			kfree(fp);
			continue;
		}

		snd_printdd(KERN_INFO "%d:%u:%d: add audio endpoint 0x%x\n", dev->devnum, iface_no, i, fp->endpoint);
		err = add_audio_endpoint(chip, stream, fp);
		if (err < 0) {
			kfree(fp->rate_table);
			kfree(fp);
			return err;
		}
		/* try to set the interface... */
		usb_set_interface(chip->dev, iface_no, altno);
		init_usb_pitch(chip->dev, iface_no, alts, fp);
		init_usb_sample_rate(chip->dev, iface_no, alts, fp, fp->rate_max);
	}
	return 0;
}


/*
 * disconnect streams
 * called from snd_usb_audio_disconnect()
 */
static void snd_usb_stream_disconnect(struct list_head *head)
{
	int idx;
	snd_usb_stream_t *as;
	snd_usb_substream_t *subs;

	as = list_entry(head, snd_usb_stream_t, list);
	for (idx = 0; idx < 2; idx++) {
		subs = &as->substream[idx];
		if (!subs->num_formats)
			return;
		release_substream_urbs(subs, 1);
		subs->interface = -1;
	}
}

/*
 * parse audio control descriptor and create pcm/midi streams
 */
static int snd_usb_create_streams(snd_usb_audio_t *chip, int ctrlif)
{
	struct usb_device *dev = chip->dev;
	struct usb_host_interface *host_iface;
	struct usb_interface *iface;
	unsigned char *p1;
	int i, j;

	/* find audiocontrol interface */
	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
	if (!(p1 = snd_usb_find_csint_desc(host_iface->extra, host_iface->extralen, NULL, HEADER))) {
		snd_printk(KERN_ERR "cannot find HEADER\n");
		return -EINVAL;
	}
	if (! p1[7] || p1[0] < 8 + p1[7]) {
		snd_printk(KERN_ERR "invalid HEADER\n");
		return -EINVAL;
	}

	/*
	 * parse all USB audio streaming interfaces
	 */
	for (i = 0; i < p1[7]; i++) {
		struct usb_host_interface *alts;
		struct usb_interface_descriptor *altsd;
		j = p1[8 + i];
		iface = usb_ifnum_to_if(dev, j);
		if (!iface) {
			snd_printk(KERN_ERR "%d:%u:%d : does not exist\n",
				   dev->devnum, ctrlif, j);
			continue;
		}
		if (usb_interface_claimed(iface)) {
			snd_printdd(KERN_INFO "%d:%d:%d: skipping, already claimed\n", dev->devnum, ctrlif, j);
			continue;
		}
		alts = &iface->altsetting[0];
		altsd = get_iface_desc(alts);
		if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
		     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
		    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDI_STREAMING) {
			if (snd_usb_create_midi_interface(chip, iface, NULL) < 0) {
				snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n", dev->devnum, ctrlif, j);
				continue;
			}
			usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
			continue;
		}
		if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
		     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
		    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIO_STREAMING) {
			snd_printdd(KERN_ERR "%d:%u:%d: skipping non-supported interface %d\n", dev->devnum, ctrlif, j, altsd->bInterfaceClass);
			/* skip non-supported classes */
			continue;
		}
		if (! parse_audio_endpoints(chip, j)) {
			usb_set_interface(dev, j, 0); /* reset the current interface */
			usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
		}
	}

	return 0;
}

/*
 * create a stream for an endpoint/altsetting without proper descriptors
 */
static int create_fixed_stream_quirk(snd_usb_audio_t *chip,
				     struct usb_interface *iface,
				     const snd_usb_audio_quirk_t *quirk)
{
	struct audioformat *fp;
	struct usb_host_interface *alts;
	int stream, err;
	int *rate_table = NULL;

	fp = kmalloc(sizeof(*fp), GFP_KERNEL);
	if (! fp) {
		snd_printk(KERN_ERR "cannot malloc\n");
		return -ENOMEM;
	}
	memcpy(fp, quirk->data, sizeof(*fp));
	if (fp->nr_rates > 0) {
		rate_table = kmalloc(sizeof(int) * fp->nr_rates, GFP_KERNEL);
		if (!rate_table) {
			kfree(fp);
			return -ENOMEM;
		}
		memcpy(rate_table, fp->rate_table, sizeof(int) * fp->nr_rates);
		fp->rate_table = rate_table;
	}

	stream = (fp->endpoint & USB_DIR_IN)
		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
	err = add_audio_endpoint(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];
	usb_set_interface(chip->dev, fp->iface, 0);
	init_usb_pitch(chip->dev, fp->iface, alts, fp);
	init_usb_sample_rate(chip->dev, fp->iface, alts, fp, fp->rate_max);
	return 0;
}

/*
 * create a stream for an interface with proper descriptors
 */
static int create_standard_interface_quirk(snd_usb_audio_t *chip,
					   struct usb_interface *iface,
					   const snd_usb_audio_quirk_t *quirk)
{
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	int err;

	alts = &iface->altsetting[0];
	altsd = get_iface_desc(alts);
	switch (quirk->type) {
	case QUIRK_AUDIO_STANDARD_INTERFACE:
		err = parse_audio_endpoints(chip, altsd->bInterfaceNumber);
		if (!err)
			usb_set_interface(chip->dev, altsd->bInterfaceNumber, 0); /* reset the current interface */
		break;
	case QUIRK_MIDI_STANDARD_INTERFACE:
		err = snd_usb_create_midi_interface(chip, iface, NULL);
		break;
	default:
		snd_printd(KERN_ERR "invalid quirk type %d\n", quirk->type);
		return -ENXIO;
	}
	if (err < 0) {
		snd_printk(KERN_ERR "cannot setup if %d: error %d\n",
			   altsd->bInterfaceNumber, err);
		return err;
	}
	return 0;
}

/*
 * Create a stream for an Edirol UA-700/UA-25 interface.  The only way
 * to detect the sample rate is by looking at wMaxPacketSize.
 */
static int create_ua700_ua25_quirk(snd_usb_audio_t *chip,
				   struct usb_interface *iface,
				   const snd_usb_audio_quirk_t *quirk)
{
	static const struct audioformat ua_format = {
		.format = SNDRV_PCM_FORMAT_S24_3LE,
		.channels = 2,
		.fmt_type = USB_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 altsettings */
	if (iface->num_altsetting != 2)
		return -ENXIO;
	alts = &iface->altsetting[1];
	altsd = get_iface_desc(alts);

	if (altsd->bNumEndpoints == 2) {
		static const snd_usb_midi_endpoint_info_t ua700_ep = {
			.out_cables = 0x0003,
			.in_cables  = 0x0003
		};
		static const snd_usb_audio_quirk_t ua700_quirk = {
			.type = QUIRK_MIDI_FIXED_ENDPOINT,
			.data = &ua700_ep
		};
		static const snd_usb_midi_endpoint_info_t ua25_ep = {
			.out_cables = 0x0001,
			.in_cables  = 0x0001
		};
		static const snd_usb_audio_quirk_t ua25_quirk = {
			.type = QUIRK_MIDI_FIXED_ENDPOINT,
			.data = &ua25_ep
		};
		if (chip->usb_id == USB_ID(0x0582, 0x002b))
			return snd_usb_create_midi_interface(chip, iface,
							     &ua700_quirk);
		else
			return snd_usb_create_midi_interface(chip, iface,
							     &ua25_quirk);
	}

	if (altsd->bNumEndpoints != 1)
		return -ENXIO;

	fp = kmalloc(sizeof(*fp), GFP_KERNEL);
	if (!fp)
		return -ENOMEM;
	memcpy(fp, &ua_format, sizeof(*fp));

	fp->iface = altsd->bInterfaceNumber;
	fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
	fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
	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:
		snd_printk(KERN_ERR "unknown sample rate\n");
		kfree(fp);
		return -ENXIO;
	}

	stream = (fp->endpoint & USB_DIR_IN)
		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
	err = add_audio_endpoint(chip, stream, fp);
	if (err < 0) {
		kfree(fp);
		return err;
	}
	usb_set_interface(chip->dev, fp->iface, 0);
	return 0;
}

/*
 * Create a stream for an Edirol UA-1000 interface.
 */
static int create_ua1000_quirk(snd_usb_audio_t *chip,
			       struct usb_interface *iface,
			       const snd_usb_audio_quirk_t *quirk)
{
	static const struct audioformat ua1000_format = {
		.format = SNDRV_PCM_FORMAT_S32_LE,
		.fmt_type = USB_FORMAT_TYPE_I,
		.altsetting = 1,
		.altset_idx = 1,
		.attributes = 0,
		.rates = SNDRV_PCM_RATE_CONTINUOUS,
	};
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	struct audioformat *fp;
	int stream, err;

	if (iface->num_altsetting != 2)
		return -ENXIO;
	alts = &iface->altsetting[1];
	altsd = get_iface_desc(alts);
	if (alts->extralen != 11 || alts->extra[1] != CS_AUDIO_INTERFACE ||
	    altsd->bNumEndpoints != 1)
		return -ENXIO;

	fp = kmalloc(sizeof(*fp), GFP_KERNEL);
	if (!fp)
		return -ENOMEM;
	memcpy(fp, &ua1000_format, sizeof(*fp));

	fp->channels = alts->extra[4];
	fp->iface = altsd->bInterfaceNumber;
	fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
	fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
	fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
	fp->rate_max = fp->rate_min = combine_triple(&alts->extra[8]);

	stream = (fp->endpoint & USB_DIR_IN)
		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
	err = add_audio_endpoint(chip, stream, fp);
	if (err < 0) {
		kfree(fp);
		return err;
	}
	/* FIXME: playback must be synchronized to capture */
	usb_set_interface(chip->dev, fp->iface, 0);
	return 0;
}

static int snd_usb_create_quirk(snd_usb_audio_t *chip,
				struct usb_interface *iface,
				const snd_usb_audio_quirk_t *quirk);

/*
 * handle the quirks for the contained interfaces
 */
static int create_composite_quirk(snd_usb_audio_t *chip,
				  struct usb_interface *iface,
				  const snd_usb_audio_quirk_t *quirk)
{
	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
	int err;

	for (quirk = quirk->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, quirk);
		if (err < 0)
			return err;
		if (quirk->ifnum != probed_ifnum)
			usb_driver_claim_interface(&usb_audio_driver, iface, (void *)-1L);
	}
	return 0;
}

static int ignore_interface_quirk(snd_usb_audio_t *chip,
				  struct usb_interface *iface,
				  const snd_usb_audio_quirk_t *quirk)
{
	return 0;
}


/*
 * 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) {
		snd_printdd("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, 1000);
		if (err < 0) snd_printdd("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) snd_printdd("error usb_get_descriptor: %d\n", err);
		err = usb_reset_configuration(dev);
		if (err < 0) snd_printdd("error usb_reset_configuration: %d\n", err);
		snd_printdd("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, 1000);
	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, 1000);
		return -ENODEV;
	}
	return 0;
}


/*
 * audio-interface quirks
 *
 * returns zero if no standard audio/MIDI parsing is needed.
 * returns a postive value if standard audio/midi interfaces are parsed
 * after this.
 * returns a negative value at error.
 */
static int snd_usb_create_quirk(snd_usb_audio_t *chip,
				struct usb_interface *iface,
				const snd_usb_audio_quirk_t *quirk)
{
	typedef int (*quirk_func_t)(snd_usb_audio_t *, struct usb_interface *,
				    const snd_usb_audio_quirk_t *);
	static const quirk_func_t quirk_funcs[] = {
		[QUIRK_IGNORE_INTERFACE] = ignore_interface_quirk,
		[QUIRK_COMPOSITE] = create_composite_quirk,
		[QUIRK_MIDI_STANDARD_INTERFACE] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_FIXED_ENDPOINT] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_YAMAHA] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_MIDIMAN] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_NOVATION] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_RAW] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_EMAGIC] = snd_usb_create_midi_interface,
		[QUIRK_MIDI_MIDITECH] = snd_usb_create_midi_interface,
		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_interface_quirk,
		[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
		[QUIRK_AUDIO_EDIROL_UA700_UA25] = create_ua700_ua25_quirk,
		[QUIRK_AUDIO_EDIROL_UA1000] = create_ua1000_quirk,
	};

	if (quirk->type < QUIRK_TYPE_COUNT) {
		return quirk_funcs[quirk->type](chip, iface, quirk);
	} else {
		snd_printd(KERN_ERR "invalid quirk type %d\n", quirk->type);
		return -ENXIO;
	}
}


/*
 * common proc files to show the usb device info
 */
static void proc_audio_usbbus_read(snd_info_entry_t *entry, snd_info_buffer_t *buffer)
{
	snd_usb_audio_t *chip = entry->private_data;
	if (! chip->shutdown)
		snd_iprintf(buffer, "%03d/%03d\n", chip->dev->bus->busnum, chip->dev->devnum);
}

static void proc_audio_usbid_read(snd_info_entry_t *entry, snd_info_buffer_t *buffer)
{
	snd_usb_audio_t *chip = entry->private_data;
	if (! chip->shutdown)
		snd_iprintf(buffer, "%04x:%04x\n", 
			    USB_ID_VENDOR(chip->usb_id),
			    USB_ID_PRODUCT(chip->usb_id));
}

static void snd_usb_audio_create_proc(snd_usb_audio_t *chip)
{
	snd_info_entry_t *entry;
	if (! snd_card_proc_new(chip->card, "usbbus", &entry))
		snd_info_set_text_ops(entry, chip, 1024, proc_audio_usbbus_read);
	if (! snd_card_proc_new(chip->card, "usbid", &entry))
		snd_info_set_text_ops(entry, chip, 1024, proc_audio_usbid_read);
}

/*
 * free the chip instance
 *
 * here we have to do not much, since pcm and controls are already freed
 *
 */

static int snd_usb_audio_free(snd_usb_audio_t *chip)
{
	kfree(chip);
	return 0;
}

static int snd_usb_audio_dev_free(snd_device_t *device)
{
	snd_usb_audio_t *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_device *dev, int idx,
				const snd_usb_audio_quirk_t *quirk,
				snd_usb_audio_t **rchip)
{
	snd_card_t *card;
	snd_usb_audio_t *chip;
	int err, len;
	char component[14];
	static snd_device_ops_t ops = {
		.dev_free =	snd_usb_audio_dev_free,
	};

	*rchip = NULL;

	if (snd_usb_get_speed(dev) != USB_SPEED_FULL &&
	    snd_usb_get_speed(dev) != USB_SPEED_HIGH) {
		snd_printk(KERN_ERR "unknown device speed %d\n", snd_usb_get_speed(dev));
		return -ENXIO;
	}

	card = snd_card_new(index[idx], id[idx], THIS_MODULE, 0);
	if (card == NULL) {
		snd_printk(KERN_ERR "cannot create card instance %d\n", idx);
		return -ENOMEM;
	}

	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
	if (! chip) {
		snd_card_free(card);
		return -ENOMEM;
	}

	chip->index = idx;
	chip->dev = dev;
	chip->card = card;
	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->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) {
		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));
		}
	}

	/* retrieve the vendor and device strings as longname */
	if (quirk && 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)
		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);

	strlcat(card->longname,
		snd_usb_get_speed(dev) == USB_SPEED_FULL ? ", full speed" : ", high speed",
		sizeof(card->longname));

	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 void *snd_usb_audio_probe(struct usb_device *dev,
				 struct usb_interface *intf,
				 const struct usb_device_id *usb_id)
{
	struct usb_host_config *config = dev->actconfig;
	const snd_usb_audio_quirk_t *quirk = (const snd_usb_audio_quirk_t *)usb_id->driver_info;
	int i, err;
	snd_usb_audio_t *chip;
	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)
		goto __err_val;

	/* SB Extigy needs special boot-up sequence */
	/* if more models come, this will go to the quirk list. */
	if (id == USB_ID(0x041e, 0x3000)) {
		if (snd_usb_extigy_boot_quirk(dev, intf) < 0)
			goto __err_val;
		config = dev->actconfig;
	}
	/* SB Audigy 2 NX needs its own boot-up magic, too */
	if (id == USB_ID(0x041e, 0x3020)) {
		if (snd_usb_audigy2nx_boot_quirk(dev) < 0)
			goto __err_val;
	}

	/*
	 * found a config.  now register to ALSA
	 */

	/* check whether it's already registered */
	chip = NULL;
	down(&register_mutex);
	for (i = 0; i < SNDRV_CARDS; i++) {
		if (usb_chip[i] && usb_chip[i]->dev == dev) {
			if (usb_chip[i]->shutdown) {
				snd_printk(KERN_ERR "USB device is in the shutdown state, cannot create a card instance\n");
				goto __error;
			}
			chip = usb_chip[i];
			break;
		}
	}
	if (! chip) {
		/* it's a fresh one.
		 * now look for an empty slot and create a new card instance
		 */
		/* first, set the current configuration for this device */
		if (usb_reset_configuration(dev) < 0) {
			snd_printk(KERN_ERR "cannot reset configuration (value 0x%x)\n", get_cfg_desc(config)->bConfigurationValue);
			goto __error;
		}
		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))) {
				if (snd_usb_audio_create(dev, i, quirk, &chip) < 0) {
					goto __error;
				}
				snd_card_set_dev(chip->card, &intf->dev);
				break;
			}
		if (! chip) {
			snd_printk(KERN_ERR "no available usb audio device\n");
			goto __error;
		}
	}

	err = 1; /* continue */
	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
		/* need some special handlings */
		if ((err = snd_usb_create_quirk(chip, intf, quirk)) < 0)
			goto __error;
	}

	if (err > 0) {
		/* create normal USB audio interfaces */
		if (snd_usb_create_streams(chip, ifnum) < 0 ||
		    snd_usb_create_mixer(chip, ifnum) < 0) {
			goto __error;
		}
	}

	/* we are allowed to call snd_card_register() many times */
	if (snd_card_register(chip->card) < 0) {
		goto __error;
	}

	usb_chip[chip->index] = chip;
	chip->num_interfaces++;
	up(&register_mutex);
	return chip;

 __error:
	if (chip && !chip->num_interfaces)
		snd_card_free(chip->card);
	up(&register_mutex);
 __err_val:
	return NULL;
}

/*
 * we need to take care of counter, since disconnection can be called also
 * many times as well as usb_audio_probe().
 */
static void snd_usb_audio_disconnect(struct usb_device *dev, void *ptr)
{
	snd_usb_audio_t *chip;
	snd_card_t *card;
	struct list_head *p;

	if (ptr == (void *)-1L)
		return;

	chip = ptr;
	card = chip->card;
	down(&register_mutex);
	chip->shutdown = 1;
	chip->num_interfaces--;
	if (chip->num_interfaces <= 0) {
		snd_card_disconnect(card);
		/* release the pcm resources */
		list_for_each(p, &chip->pcm_list) {
			snd_usb_stream_disconnect(p);
		}
		/* release the midi resources */
		list_for_each(p, &chip->midi_list) {
			snd_usbmidi_disconnect(p);
		}
		/* release mixer resources */
		list_for_each(p, &chip->mixer_list) {
			snd_usb_mixer_disconnect(p);
		}
		usb_chip[chip->index] = NULL;
		up(&register_mutex);
		snd_card_free(card);
	} else {
		up(&register_mutex);
	}
}

/*
 * new 2.5 USB kernel API
 */
static int usb_audio_probe(struct usb_interface *intf,
			   const struct usb_device_id *id)
{
	void *chip;
	chip = snd_usb_audio_probe(interface_to_usbdev(intf), intf, id);
	if (chip) {
		dev_set_drvdata(&intf->dev, chip);
		return 0;
	} else
		return -EIO;
}

static void usb_audio_disconnect(struct usb_interface *intf)
{
	snd_usb_audio_disconnect(interface_to_usbdev(intf),
				 dev_get_drvdata(&intf->dev));
}


static int __init snd_usb_audio_init(void)
{
	if (nrpacks < MIN_PACKS_URB || nrpacks > MAX_PACKS) {
		printk(KERN_WARNING "invalid nrpacks value.\n");
		return -EINVAL;
	}
	usb_register(&usb_audio_driver);
	return 0;
}


static void __exit snd_usb_audio_cleanup(void)
{
	usb_deregister(&usb_audio_driver);
}

module_init(snd_usb_audio_init);
module_exit(snd_usb_audio_cleanup);