root/sound/usb/clock.c

DEFINITIONS

1. find_uac_clock_desc
2. validate_clock_source_v2
3. validate_clock_source_v3
4. validate_clock_selector_v2
5. validate_clock_selector_v3
6. validate_clock_multiplier_v2
7. validate_clock_multiplier_v3
8. uac_clock_selector_get_val
9. uac_clock_selector_set_val
10. uac_clock_source_is_valid_quirk
11. uac_clock_source_is_valid
12. __uac_clock_find_source
13. __uac3_clock_find_source
14. snd_usb_clock_find_source
15. set_sample_rate_v1
16. get_sample_rate_v2v3
17. set_sample_rate_v2v3
18. snd_usb_init_sample_rate

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   Clock domain and sample rate management functions
   4  */
   5 
   6 #include <linux/bitops.h>
   7 #include <linux/init.h>
   8 #include <linux/string.h>
   9 #include <linux/usb.h>
  10 #include <linux/usb/audio.h>
  11 #include <linux/usb/audio-v2.h>
  12 #include <linux/usb/audio-v3.h>
  13 
  14 #include <sound/core.h>
  15 #include <sound/info.h>
  16 #include <sound/pcm.h>
  17 
  18 #include "usbaudio.h"
  19 #include "card.h"
  20 #include "helper.h"
  21 #include "clock.h"
  22 #include "quirks.h"
  23 
  24 static void *find_uac_clock_desc(struct usb_host_interface *iface, int id,
  25                                  bool (*validator)(void *, int), u8 type)
  26 {
  27         void *cs = NULL;
  28 
  29         while ((cs = snd_usb_find_csint_desc(iface->extra, iface->extralen,
  30                                              cs, type))) {
  31                 if (validator(cs, id))
  32                         return cs;
  33         }
  34 
  35         return NULL;
  36 }
  37 
  38 static bool validate_clock_source_v2(void *p, int id)
  39 {
  40         struct uac_clock_source_descriptor *cs = p;
  41         return cs->bClockID == id;
  42 }
  43 
  44 static bool validate_clock_source_v3(void *p, int id)
  45 {
  46         struct uac3_clock_source_descriptor *cs = p;
  47         return cs->bClockID == id;
  48 }
  49 
  50 static bool validate_clock_selector_v2(void *p, int id)
  51 {
  52         struct uac_clock_selector_descriptor *cs = p;
  53         return cs->bClockID == id;
  54 }
  55 
  56 static bool validate_clock_selector_v3(void *p, int id)
  57 {
  58         struct uac3_clock_selector_descriptor *cs = p;
  59         return cs->bClockID == id;
  60 }
  61 
  62 static bool validate_clock_multiplier_v2(void *p, int id)
  63 {
  64         struct uac_clock_multiplier_descriptor *cs = p;
  65         return cs->bClockID == id;
  66 }
  67 
  68 static bool validate_clock_multiplier_v3(void *p, int id)
  69 {
  70         struct uac3_clock_multiplier_descriptor *cs = p;
  71         return cs->bClockID == id;
  72 }
  73 
  74 #define DEFINE_FIND_HELPER(name, obj, validator, type)          \
  75 static obj *name(struct usb_host_interface *iface, int id)      \
  76 {                                                               \
  77         return find_uac_clock_desc(iface, id, validator, type); \
  78 }
  79 
  80 DEFINE_FIND_HELPER(snd_usb_find_clock_source,
  81                    struct uac_clock_source_descriptor,
  82                    validate_clock_source_v2, UAC2_CLOCK_SOURCE);
  83 DEFINE_FIND_HELPER(snd_usb_find_clock_source_v3,
  84                    struct uac3_clock_source_descriptor,
  85                    validate_clock_source_v3, UAC3_CLOCK_SOURCE);
  86 
  87 DEFINE_FIND_HELPER(snd_usb_find_clock_selector,
  88                    struct uac_clock_selector_descriptor,
  89                    validate_clock_selector_v2, UAC2_CLOCK_SELECTOR);
  90 DEFINE_FIND_HELPER(snd_usb_find_clock_selector_v3,
  91                    struct uac3_clock_selector_descriptor,
  92                    validate_clock_selector_v3, UAC3_CLOCK_SELECTOR);
  93 
  94 DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier,
  95                    struct uac_clock_multiplier_descriptor,
  96                    validate_clock_multiplier_v2, UAC2_CLOCK_MULTIPLIER);
  97 DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier_v3,
  98                    struct uac3_clock_multiplier_descriptor,
  99                    validate_clock_multiplier_v3, UAC3_CLOCK_MULTIPLIER);
 100 
 101 static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
 102 {
 103         unsigned char buf;
 104         int ret;
 105 
 106         ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
 107                               UAC2_CS_CUR,
 108                               USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 109                               UAC2_CX_CLOCK_SELECTOR << 8,
 110                               snd_usb_ctrl_intf(chip) | (selector_id << 8),
 111                               &buf, sizeof(buf));
 112 
 113         if (ret < 0)
 114                 return ret;
 115 
 116         return buf;
 117 }
 118 
 119 static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
 120                                         unsigned char pin)
 121 {
 122         int ret;
 123 
 124         ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
 125                               UAC2_CS_CUR,
 126                               USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
 127                               UAC2_CX_CLOCK_SELECTOR << 8,
 128                               snd_usb_ctrl_intf(chip) | (selector_id << 8),
 129                               &pin, sizeof(pin));
 130         if (ret < 0)
 131                 return ret;
 132 
 133         if (ret != sizeof(pin)) {
 134                 usb_audio_err(chip,
 135                         "setting selector (id %d) unexpected length %d\n",
 136                         selector_id, ret);
 137                 return -EINVAL;
 138         }
 139 
 140         ret = uac_clock_selector_get_val(chip, selector_id);
 141         if (ret < 0)
 142                 return ret;
 143 
 144         if (ret != pin) {
 145                 usb_audio_err(chip,
 146                         "setting selector (id %d) to %x failed (current: %d)\n",
 147                         selector_id, pin, ret);
 148                 return -EINVAL;
 149         }
 150 
 151         return ret;
 152 }
 153 
 154 /*
 155  * Assume the clock is valid if clock source supports only one single sample
 156  * rate, the terminal is connected directly to it (there is no clock selector)
 157  * and clock type is internal. This is to deal with some Denon DJ controllers
 158  * that always reports that clock is invalid.
 159  */
 160 static bool uac_clock_source_is_valid_quirk(struct snd_usb_audio *chip,
 161                                             struct audioformat *fmt,
 162                                             int source_id)
 163 {
 164         if (fmt->protocol == UAC_VERSION_2) {
 165                 struct uac_clock_source_descriptor *cs_desc =
 166                         snd_usb_find_clock_source(chip->ctrl_intf, source_id);
 167 
 168                 if (!cs_desc)
 169                         return false;
 170 
 171                 return (fmt->nr_rates == 1 &&
 172                         (fmt->clock & 0xff) == cs_desc->bClockID &&
 173                         (cs_desc->bmAttributes & 0x3) !=
 174                                 UAC_CLOCK_SOURCE_TYPE_EXT);
 175         }
 176 
 177         return false;
 178 }
 179 
 180 static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
 181                                       struct audioformat *fmt,
 182                                       int source_id)
 183 {
 184         int err;
 185         unsigned char data;
 186         struct usb_device *dev = chip->dev;
 187         u32 bmControls;
 188 
 189         if (fmt->protocol == UAC_VERSION_3) {
 190                 struct uac3_clock_source_descriptor *cs_desc =
 191                         snd_usb_find_clock_source_v3(chip->ctrl_intf, source_id);
 192 
 193                 if (!cs_desc)
 194                         return false;
 195                 bmControls = le32_to_cpu(cs_desc->bmControls);
 196         } else { /* UAC_VERSION_1/2 */
 197                 struct uac_clock_source_descriptor *cs_desc =
 198                         snd_usb_find_clock_source(chip->ctrl_intf, source_id);
 199 
 200                 if (!cs_desc)
 201                         return false;
 202                 bmControls = cs_desc->bmControls;
 203         }
 204 
 205         /* If a clock source can't tell us whether it's valid, we assume it is */
 206         if (!uac_v2v3_control_is_readable(bmControls,
 207                                       UAC2_CS_CONTROL_CLOCK_VALID))
 208                 return true;
 209 
 210         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 211                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 212                               UAC2_CS_CONTROL_CLOCK_VALID << 8,
 213                               snd_usb_ctrl_intf(chip) | (source_id << 8),
 214                               &data, sizeof(data));
 215 
 216         if (err < 0) {
 217                 dev_warn(&dev->dev,
 218                          "%s(): cannot get clock validity for id %d\n",
 219                            __func__, source_id);
 220                 return false;
 221         }
 222 
 223         if (data)
 224                 return true;
 225         else
 226                 return uac_clock_source_is_valid_quirk(chip, fmt, source_id);
 227 }
 228 
 229 static int __uac_clock_find_source(struct snd_usb_audio *chip,
 230                                    struct audioformat *fmt, int entity_id,
 231                                    unsigned long *visited, bool validate)
 232 {
 233         struct uac_clock_source_descriptor *source;
 234         struct uac_clock_selector_descriptor *selector;
 235         struct uac_clock_multiplier_descriptor *multiplier;
 236 
 237         entity_id &= 0xff;
 238 
 239         if (test_and_set_bit(entity_id, visited)) {
 240                 usb_audio_warn(chip,
 241                          "%s(): recursive clock topology detected, id %d.\n",
 242                          __func__, entity_id);
 243                 return -EINVAL;
 244         }
 245 
 246         /* first, see if the ID we're looking for is a clock source already */
 247         source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
 248         if (source) {
 249                 entity_id = source->bClockID;
 250                 if (validate && !uac_clock_source_is_valid(chip, fmt,
 251                                                                 entity_id)) {
 252                         usb_audio_err(chip,
 253                                 "clock source %d is not valid, cannot use\n",
 254                                 entity_id);
 255                         return -ENXIO;
 256                 }
 257                 return entity_id;
 258         }
 259 
 260         selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
 261         if (selector) {
 262                 int ret, i, cur;
 263 
 264                 /* the entity ID we are looking for is a selector.
 265                  * find out what it currently selects */
 266                 ret = uac_clock_selector_get_val(chip, selector->bClockID);
 267                 if (ret < 0)
 268                         return ret;
 269 
 270                 /* Selector values are one-based */
 271 
 272                 if (ret > selector->bNrInPins || ret < 1) {
 273                         usb_audio_err(chip,
 274                                 "%s(): selector reported illegal value, id %d, ret %d\n",
 275                                 __func__, selector->bClockID, ret);
 276 
 277                         return -EINVAL;
 278                 }
 279 
 280                 cur = ret;
 281                 ret = __uac_clock_find_source(chip, fmt,
 282                                               selector->baCSourceID[ret - 1],
 283                                               visited, validate);
 284                 if (!validate || ret > 0 || !chip->autoclock)
 285                         return ret;
 286 
 287                 /* The current clock source is invalid, try others. */
 288                 for (i = 1; i <= selector->bNrInPins; i++) {
 289                         int err;
 290 
 291                         if (i == cur)
 292                                 continue;
 293 
 294                         ret = __uac_clock_find_source(chip, fmt,
 295                                                       selector->baCSourceID[i - 1],
 296                                                       visited, true);
 297                         if (ret < 0)
 298                                 continue;
 299 
 300                         err = uac_clock_selector_set_val(chip, entity_id, i);
 301                         if (err < 0)
 302                                 continue;
 303 
 304                         usb_audio_info(chip,
 305                                  "found and selected valid clock source %d\n",
 306                                  ret);
 307                         return ret;
 308                 }
 309 
 310                 return -ENXIO;
 311         }
 312 
 313         /* FIXME: multipliers only act as pass-thru element for now */
 314         multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
 315         if (multiplier)
 316                 return __uac_clock_find_source(chip, fmt,
 317                                                multiplier->bCSourceID,
 318                                                visited, validate);
 319 
 320         return -EINVAL;
 321 }
 322 
 323 static int __uac3_clock_find_source(struct snd_usb_audio *chip,
 324                                     struct audioformat *fmt, int entity_id,
 325                                     unsigned long *visited, bool validate)
 326 {
 327         struct uac3_clock_source_descriptor *source;
 328         struct uac3_clock_selector_descriptor *selector;
 329         struct uac3_clock_multiplier_descriptor *multiplier;
 330 
 331         entity_id &= 0xff;
 332 
 333         if (test_and_set_bit(entity_id, visited)) {
 334                 usb_audio_warn(chip,
 335                          "%s(): recursive clock topology detected, id %d.\n",
 336                          __func__, entity_id);
 337                 return -EINVAL;
 338         }
 339 
 340         /* first, see if the ID we're looking for is a clock source already */
 341         source = snd_usb_find_clock_source_v3(chip->ctrl_intf, entity_id);
 342         if (source) {
 343                 entity_id = source->bClockID;
 344                 if (validate && !uac_clock_source_is_valid(chip, fmt,
 345                                                                 entity_id)) {
 346                         usb_audio_err(chip,
 347                                 "clock source %d is not valid, cannot use\n",
 348                                 entity_id);
 349                         return -ENXIO;
 350                 }
 351                 return entity_id;
 352         }
 353 
 354         selector = snd_usb_find_clock_selector_v3(chip->ctrl_intf, entity_id);
 355         if (selector) {
 356                 int ret, i, cur;
 357 
 358                 /* the entity ID we are looking for is a selector.
 359                  * find out what it currently selects */
 360                 ret = uac_clock_selector_get_val(chip, selector->bClockID);
 361                 if (ret < 0)
 362                         return ret;
 363 
 364                 /* Selector values are one-based */
 365 
 366                 if (ret > selector->bNrInPins || ret < 1) {
 367                         usb_audio_err(chip,
 368                                 "%s(): selector reported illegal value, id %d, ret %d\n",
 369                                 __func__, selector->bClockID, ret);
 370 
 371                         return -EINVAL;
 372                 }
 373 
 374                 cur = ret;
 375                 ret = __uac3_clock_find_source(chip, fmt,
 376                                                selector->baCSourceID[ret - 1],
 377                                                visited, validate);
 378                 if (!validate || ret > 0 || !chip->autoclock)
 379                         return ret;
 380 
 381                 /* The current clock source is invalid, try others. */
 382                 for (i = 1; i <= selector->bNrInPins; i++) {
 383                         int err;
 384 
 385                         if (i == cur)
 386                                 continue;
 387 
 388                         ret = __uac3_clock_find_source(chip, fmt,
 389                                                        selector->baCSourceID[i - 1],
 390                                                        visited, true);
 391                         if (ret < 0)
 392                                 continue;
 393 
 394                         err = uac_clock_selector_set_val(chip, entity_id, i);
 395                         if (err < 0)
 396                                 continue;
 397 
 398                         usb_audio_info(chip,
 399                                  "found and selected valid clock source %d\n",
 400                                  ret);
 401                         return ret;
 402                 }
 403 
 404                 return -ENXIO;
 405         }
 406 
 407         /* FIXME: multipliers only act as pass-thru element for now */
 408         multiplier = snd_usb_find_clock_multiplier_v3(chip->ctrl_intf,
 409                                                       entity_id);
 410         if (multiplier)
 411                 return __uac3_clock_find_source(chip, fmt,
 412                                                 multiplier->bCSourceID,
 413                                                 visited, validate);
 414 
 415         return -EINVAL;
 416 }
 417 
 418 /*
 419  * For all kinds of sample rate settings and other device queries,
 420  * the clock source (end-leaf) must be used. However, clock selectors,
 421  * clock multipliers and sample rate converters may be specified as
 422  * clock source input to terminal. This functions walks the clock path
 423  * to its end and tries to find the source.
 424  *
 425  * The 'visited' bitfield is used internally to detect recursive loops.
 426  *
 427  * Returns the clock source UnitID (>=0) on success, or an error.
 428  */
 429 int snd_usb_clock_find_source(struct snd_usb_audio *chip,
 430                               struct audioformat *fmt, bool validate)
 431 {
 432         DECLARE_BITMAP(visited, 256);
 433         memset(visited, 0, sizeof(visited));
 434 
 435         switch (fmt->protocol) {
 436         case UAC_VERSION_2:
 437                 return __uac_clock_find_source(chip, fmt, fmt->clock, visited,
 438                                                validate);
 439         case UAC_VERSION_3:
 440                 return __uac3_clock_find_source(chip, fmt, fmt->clock, visited,
 441                                                validate);
 442         default:
 443                 return -EINVAL;
 444         }
 445 }
 446 
 447 static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
 448                               struct usb_host_interface *alts,
 449                               struct audioformat *fmt, int rate)
 450 {
 451         struct usb_device *dev = chip->dev;
 452         unsigned int ep;
 453         unsigned char data[3];
 454         int err, crate;
 455 
 456         if (get_iface_desc(alts)->bNumEndpoints < 1)
 457                 return -EINVAL;
 458         ep = get_endpoint(alts, 0)->bEndpointAddress;
 459 
 460         /* if endpoint doesn't have sampling rate control, bail out */
 461         if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
 462                 return 0;
 463 
 464         data[0] = rate;
 465         data[1] = rate >> 8;
 466         data[2] = rate >> 16;
 467         err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 468                               USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 469                               UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
 470                               data, sizeof(data));
 471         if (err < 0) {
 472                 dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
 473                         iface, fmt->altsetting, rate, ep);
 474                 return err;
 475         }
 476 
 477         /* Don't check the sample rate for devices which we know don't
 478          * support reading */
 479         if (snd_usb_get_sample_rate_quirk(chip))
 480                 return 0;
 481         /* the firmware is likely buggy, don't repeat to fail too many times */
 482         if (chip->sample_rate_read_error > 2)
 483                 return 0;
 484 
 485         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
 486                               USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
 487                               UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
 488                               data, sizeof(data));
 489         if (err < 0) {
 490                 dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
 491                         iface, fmt->altsetting, ep);
 492                 chip->sample_rate_read_error++;
 493                 return 0; /* some devices don't support reading */
 494         }
 495 
 496         crate = data[0] | (data[1] << 8) | (data[2] << 16);
 497         if (crate != rate) {
 498                 dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
 499                 // runtime->rate = crate;
 500         }
 501 
 502         return 0;
 503 }
 504 
 505 static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
 506                               int altsetting, int clock)
 507 {
 508         struct usb_device *dev = chip->dev;
 509         __le32 data;
 510         int err;
 511 
 512         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 513                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 514                               UAC2_CS_CONTROL_SAM_FREQ << 8,
 515                               snd_usb_ctrl_intf(chip) | (clock << 8),
 516                               &data, sizeof(data));
 517         if (err < 0) {
 518                 dev_warn(&dev->dev, "%d:%d: cannot get freq (v2/v3): err %d\n",
 519                          iface, altsetting, err);
 520                 return 0;
 521         }
 522 
 523         return le32_to_cpu(data);
 524 }
 525 
 526 static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
 527                               struct usb_host_interface *alts,
 528                               struct audioformat *fmt, int rate)
 529 {
 530         struct usb_device *dev = chip->dev;
 531         __le32 data;
 532         int err, cur_rate, prev_rate;
 533         int clock;
 534         bool writeable;
 535         u32 bmControls;
 536 
 537         /* First, try to find a valid clock. This may trigger
 538          * automatic clock selection if the current clock is not
 539          * valid.
 540          */
 541         clock = snd_usb_clock_find_source(chip, fmt, true);
 542         if (clock < 0) {
 543                 /* We did not find a valid clock, but that might be
 544                  * because the current sample rate does not match an
 545                  * external clock source. Try again without validation
 546                  * and we will do another validation after setting the
 547                  * rate.
 548                  */
 549                 clock = snd_usb_clock_find_source(chip, fmt, false);
 550                 if (clock < 0)
 551                         return clock;
 552         }
 553 
 554         prev_rate = get_sample_rate_v2v3(chip, iface, fmt->altsetting, clock);
 555         if (prev_rate == rate)
 556                 goto validation;
 557 
 558         if (fmt->protocol == UAC_VERSION_3) {
 559                 struct uac3_clock_source_descriptor *cs_desc;
 560 
 561                 cs_desc = snd_usb_find_clock_source_v3(chip->ctrl_intf, clock);
 562                 bmControls = le32_to_cpu(cs_desc->bmControls);
 563         } else {
 564                 struct uac_clock_source_descriptor *cs_desc;
 565 
 566                 cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
 567                 bmControls = cs_desc->bmControls;
 568         }
 569 
 570         writeable = uac_v2v3_control_is_writeable(bmControls,
 571                                                   UAC2_CS_CONTROL_SAM_FREQ);
 572         if (writeable) {
 573                 data = cpu_to_le32(rate);
 574                 err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
 575                                       USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 576                                       UAC2_CS_CONTROL_SAM_FREQ << 8,
 577                                       snd_usb_ctrl_intf(chip) | (clock << 8),
 578                                       &data, sizeof(data));
 579                 if (err < 0) {
 580                         usb_audio_err(chip,
 581                                 "%d:%d: cannot set freq %d (v2/v3): err %d\n",
 582                                 iface, fmt->altsetting, rate, err);
 583                         return err;
 584                 }
 585 
 586                 cur_rate = get_sample_rate_v2v3(chip, iface,
 587                                                 fmt->altsetting, clock);
 588         } else {
 589                 cur_rate = prev_rate;
 590         }
 591 
 592         if (cur_rate != rate) {
 593                 if (!writeable) {
 594                         usb_audio_warn(chip,
 595                                  "%d:%d: freq mismatch (RO clock): req %d, clock runs @%d\n",
 596                                  iface, fmt->altsetting, rate, cur_rate);
 597                         return -ENXIO;
 598                 }
 599                 usb_audio_dbg(chip,
 600                         "current rate %d is different from the runtime rate %d\n",
 601                         cur_rate, rate);
 602         }
 603 
 604         /* Some devices doesn't respond to sample rate changes while the
 605          * interface is active. */
 606         if (rate != prev_rate) {
 607                 usb_set_interface(dev, iface, 0);
 608                 snd_usb_set_interface_quirk(dev);
 609                 usb_set_interface(dev, iface, fmt->altsetting);
 610                 snd_usb_set_interface_quirk(dev);
 611         }
 612 
 613 validation:
 614         /* validate clock after rate change */
 615         if (!uac_clock_source_is_valid(chip, fmt, clock))
 616                 return -ENXIO;
 617         return 0;
 618 }
 619 
 620 int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
 621                              struct usb_host_interface *alts,
 622                              struct audioformat *fmt, int rate)
 623 {
 624         switch (fmt->protocol) {
 625         case UAC_VERSION_1:
 626         default:
 627                 return set_sample_rate_v1(chip, iface, alts, fmt, rate);
 628 
 629         case UAC_VERSION_3:
 630                 if (chip->badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
 631                         if (rate != UAC3_BADD_SAMPLING_RATE)
 632                                 return -ENXIO;
 633                         else
 634                                 return 0;
 635                 }
 636         /* fall through */
 637         case UAC_VERSION_2:
 638                 return set_sample_rate_v2v3(chip, iface, alts, fmt, rate);
 639         }
 640 }
 641