1 // SPDX-License-Identifier: GPL-2.0-or-later
6 #include <linux/init.h>
7 #include <linux/ratelimit.h>
9 #include <linux/usb/audio.h>
10 #include <linux/slab.h>
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 #include <sound/pcm_params.h>
30 /* interface refcounting */
31 struct snd_usb_iface_ref {
35 struct list_head list;
39 * snd_usb_endpoint is a model that abstracts everything related to an
40 * USB endpoint and its streaming.
42 * There are functions to activate and deactivate the streaming URBs and
43 * optional callbacks to let the pcm logic handle the actual content of the
44 * packets for playback and record. Thus, the bus streaming and the audio
45 * handlers are fully decoupled.
47 * There are two different types of endpoints in audio applications.
49 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
50 * inbound and outbound traffic.
52 * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
53 * expect the payload to carry Q10.14 / Q16.16 formatted sync information
56 * Each endpoint has to be configured prior to being used by calling
57 * snd_usb_endpoint_set_params().
59 * The model incorporates a reference counting, so that multiple users
60 * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
61 * only the first user will effectively start the URBs, and only the last
62 * one to stop it will tear the URBs down again.
66 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
67 * this will overflow at approx 524 kHz
69 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
71 return ((rate << 13) + 62) / 125;
75 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
76 * this will overflow at approx 4 MHz
78 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
80 return ((rate << 10) + 62) / 125;
86 static void release_urb_ctx(struct snd_urb_ctx *u)
88 if (u->urb && u->buffer_size)
89 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
90 u->urb->transfer_buffer,
91 u->urb->transfer_dma);
97 static const char *usb_error_string(int err)
103 return "endpoint not enabled";
105 return "endpoint stalled";
107 return "not enough bandwidth";
109 return "device disabled";
111 return "device suspended";
116 return "internal error";
118 return "unknown error";
122 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
124 return atomic_read(&ep->state) == EP_STATE_RUNNING;
127 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
129 return atomic_cmpxchg(&ep->state, old, new) == old;
133 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
135 * @ep: The snd_usb_endpoint
137 * Determine whether an endpoint is driven by an implicit feedback
138 * data endpoint source.
140 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
142 return ep->implicit_fb_sync && usb_pipeout(ep->pipe);
146 * Return the number of samples to be sent in the next packet
147 * for streaming based on information derived from sync endpoints
149 * This won't be used for implicit feedback which takes the packet size
150 * returned from the sync source
152 static int slave_next_packet_size(struct snd_usb_endpoint *ep,
160 return ep->maxframesize;
162 spin_lock_irqsave(&ep->lock, flags);
163 phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
164 ret = min(phase >> 16, ep->maxframesize);
165 if (avail && ret >= avail)
169 spin_unlock_irqrestore(&ep->lock, flags);
175 * Return the number of samples to be sent in the next packet
176 * for adaptive and synchronous endpoints
178 static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
180 unsigned int sample_accum;
184 return ep->maxframesize;
186 sample_accum = ep->sample_accum + ep->sample_rem;
187 if (sample_accum >= ep->pps) {
188 sample_accum -= ep->pps;
189 ret = ep->packsize[1];
191 ret = ep->packsize[0];
193 if (avail && ret >= avail)
196 ep->sample_accum = sample_accum;
202 * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
205 * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
206 * Exception: @avail = 0 for skipping the check.
208 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
209 struct snd_urb_ctx *ctx, int idx,
214 packet = ctx->packet_size[idx];
216 if (avail && packet >= avail)
222 return slave_next_packet_size(ep, avail);
224 return next_packet_size(ep, avail);
227 static void call_retire_callback(struct snd_usb_endpoint *ep,
230 struct snd_usb_substream *data_subs;
232 data_subs = READ_ONCE(ep->data_subs);
233 if (data_subs && ep->retire_data_urb)
234 ep->retire_data_urb(data_subs, urb);
237 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
238 struct snd_urb_ctx *urb_ctx)
240 call_retire_callback(ep, urb_ctx->urb);
243 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
244 struct snd_usb_endpoint *sender,
245 const struct urb *urb);
247 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
248 struct snd_urb_ctx *urb_ctx)
250 struct urb *urb = urb_ctx->urb;
251 struct snd_usb_endpoint *sync_sink;
253 if (unlikely(ep->skip_packets > 0)) {
258 sync_sink = READ_ONCE(ep->sync_sink);
260 snd_usb_handle_sync_urb(sync_sink, ep, urb);
262 call_retire_callback(ep, urb);
265 static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
267 return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
270 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
271 struct snd_urb_ctx *ctx)
273 struct urb *urb = ctx->urb;
274 unsigned int offs = 0;
275 unsigned int extra = 0;
276 __le32 packet_length;
279 /* For tx_length_quirk, put packet length at start of packet */
280 if (has_tx_length_quirk(ep->chip))
281 extra = sizeof(packet_length);
283 for (i = 0; i < ctx->packets; ++i) {
288 counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
289 length = counts * ep->stride; /* number of silent bytes */
290 offset = offs * ep->stride + extra * i;
291 urb->iso_frame_desc[i].offset = offset;
292 urb->iso_frame_desc[i].length = length + extra;
294 packet_length = cpu_to_le32(length);
295 memcpy(urb->transfer_buffer + offset,
296 &packet_length, sizeof(packet_length));
298 memset(urb->transfer_buffer + offset + extra,
299 ep->silence_value, length);
303 urb->number_of_packets = ctx->packets;
304 urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
309 * Prepare a PLAYBACK urb for submission to the bus.
311 static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
312 struct snd_urb_ctx *ctx,
315 struct urb *urb = ctx->urb;
316 unsigned char *cp = urb->transfer_buffer;
317 struct snd_usb_substream *data_subs;
319 urb->dev = ep->chip->dev; /* we need to set this at each time */
322 case SND_USB_ENDPOINT_TYPE_DATA:
323 data_subs = READ_ONCE(ep->data_subs);
324 if (data_subs && ep->prepare_data_urb)
325 return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
326 /* no data provider, so send silence */
327 prepare_silent_urb(ep, ctx);
330 case SND_USB_ENDPOINT_TYPE_SYNC:
331 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
333 * fill the length and offset of each urb descriptor.
334 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
336 urb->iso_frame_desc[0].length = 4;
337 urb->iso_frame_desc[0].offset = 0;
339 cp[1] = ep->freqn >> 8;
340 cp[2] = ep->freqn >> 16;
341 cp[3] = ep->freqn >> 24;
344 * fill the length and offset of each urb descriptor.
345 * the fixed 10.14 frequency is passed through the pipe.
347 urb->iso_frame_desc[0].length = 3;
348 urb->iso_frame_desc[0].offset = 0;
349 cp[0] = ep->freqn >> 2;
350 cp[1] = ep->freqn >> 10;
351 cp[2] = ep->freqn >> 18;
360 * Prepare a CAPTURE or SYNC urb for submission to the bus.
362 static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
363 struct snd_urb_ctx *urb_ctx)
366 struct urb *urb = urb_ctx->urb;
368 urb->dev = ep->chip->dev; /* we need to set this at each time */
371 case SND_USB_ENDPOINT_TYPE_DATA:
373 for (i = 0; i < urb_ctx->packets; i++) {
374 urb->iso_frame_desc[i].offset = offs;
375 urb->iso_frame_desc[i].length = ep->curpacksize;
376 offs += ep->curpacksize;
379 urb->transfer_buffer_length = offs;
380 urb->number_of_packets = urb_ctx->packets;
383 case SND_USB_ENDPOINT_TYPE_SYNC:
384 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
385 urb->iso_frame_desc[0].offset = 0;
391 /* notify an error as XRUN to the assigned PCM data substream */
392 static void notify_xrun(struct snd_usb_endpoint *ep)
394 struct snd_usb_substream *data_subs;
396 data_subs = READ_ONCE(ep->data_subs);
397 if (data_subs && data_subs->pcm_substream)
398 snd_pcm_stop_xrun(data_subs->pcm_substream);
401 static struct snd_usb_packet_info *
402 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
404 struct snd_usb_packet_info *p;
406 p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
407 ARRAY_SIZE(ep->next_packet);
408 ep->next_packet_queued++;
412 static struct snd_usb_packet_info *
413 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
415 struct snd_usb_packet_info *p;
417 p = ep->next_packet + ep->next_packet_head;
418 ep->next_packet_head++;
419 ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
420 ep->next_packet_queued--;
424 static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
425 struct snd_urb_ctx *ctx)
429 spin_lock_irqsave(&ep->lock, flags);
430 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
431 spin_unlock_irqrestore(&ep->lock, flags);
435 * Send output urbs that have been prepared previously. URBs are dequeued
436 * from ep->ready_playback_urbs and in case there aren't any available
437 * or there are no packets that have been prepared, this function does
440 * The reason why the functionality of sending and preparing URBs is separated
441 * is that host controllers don't guarantee the order in which they return
442 * inbound and outbound packets to their submitters.
444 * This function is used both for implicit feedback endpoints and in low-
445 * latency playback mode.
447 void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
450 bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
452 while (ep_state_running(ep)) {
455 struct snd_usb_packet_info *packet;
456 struct snd_urb_ctx *ctx = NULL;
459 spin_lock_irqsave(&ep->lock, flags);
460 if ((!implicit_fb || ep->next_packet_queued > 0) &&
461 !list_empty(&ep->ready_playback_urbs)) {
462 /* take URB out of FIFO */
463 ctx = list_first_entry(&ep->ready_playback_urbs,
464 struct snd_urb_ctx, ready_list);
465 list_del_init(&ctx->ready_list);
467 packet = next_packet_fifo_dequeue(ep);
469 spin_unlock_irqrestore(&ep->lock, flags);
474 /* copy over the length information */
476 for (i = 0; i < packet->packets; i++)
477 ctx->packet_size[i] = packet->packet_size[i];
480 /* call the data handler to fill in playback data */
481 err = prepare_outbound_urb(ep, ctx, in_stream_lock);
482 /* can be stopped during prepare callback */
483 if (unlikely(!ep_state_running(ep)))
486 /* push back to ready list again for -EAGAIN */
488 push_back_to_ready_list(ep, ctx);
494 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
496 usb_audio_err(ep->chip,
497 "Unable to submit urb #%d: %d at %s\n",
498 ctx->index, err, __func__);
503 set_bit(ctx->index, &ep->active_mask);
504 atomic_inc(&ep->submitted_urbs);
509 * complete callback for urbs
511 static void snd_complete_urb(struct urb *urb)
513 struct snd_urb_ctx *ctx = urb->context;
514 struct snd_usb_endpoint *ep = ctx->ep;
517 if (unlikely(urb->status == -ENOENT || /* unlinked */
518 urb->status == -ENODEV || /* device removed */
519 urb->status == -ECONNRESET || /* unlinked */
520 urb->status == -ESHUTDOWN)) /* device disabled */
522 /* device disconnected */
523 if (unlikely(atomic_read(&ep->chip->shutdown)))
526 if (unlikely(!ep_state_running(ep)))
529 if (usb_pipeout(ep->pipe)) {
530 retire_outbound_urb(ep, ctx);
531 /* can be stopped during retire callback */
532 if (unlikely(!ep_state_running(ep)))
535 /* in low-latency and implicit-feedback modes, push back the
536 * URB to ready list at first, then process as much as possible
538 if (ep->lowlatency_playback ||
539 snd_usb_endpoint_implicit_feedback_sink(ep)) {
540 push_back_to_ready_list(ep, ctx);
541 clear_bit(ctx->index, &ep->active_mask);
542 snd_usb_queue_pending_output_urbs(ep, false);
543 atomic_dec(&ep->submitted_urbs); /* decrement at last */
547 /* in non-lowlatency mode, no error handling for prepare */
548 prepare_outbound_urb(ep, ctx, false);
549 /* can be stopped during prepare callback */
550 if (unlikely(!ep_state_running(ep)))
553 retire_inbound_urb(ep, ctx);
554 /* can be stopped during retire callback */
555 if (unlikely(!ep_state_running(ep)))
558 prepare_inbound_urb(ep, ctx);
561 err = usb_submit_urb(urb, GFP_ATOMIC);
565 usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
569 clear_bit(ctx->index, &ep->active_mask);
570 atomic_dec(&ep->submitted_urbs);
574 * Find or create a refcount object for the given interface
576 * The objects are released altogether in snd_usb_endpoint_free_all()
578 static struct snd_usb_iface_ref *
579 iface_ref_find(struct snd_usb_audio *chip, int iface)
581 struct snd_usb_iface_ref *ip;
583 list_for_each_entry(ip, &chip->iface_ref_list, list)
584 if (ip->iface == iface)
587 ip = kzalloc(sizeof(*ip), GFP_KERNEL);
591 list_add_tail(&ip->list, &chip->iface_ref_list);
596 * Get the existing endpoint object corresponding EP
597 * Returns NULL if not present.
599 struct snd_usb_endpoint *
600 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
602 struct snd_usb_endpoint *ep;
604 list_for_each_entry(ep, &chip->ep_list, list) {
605 if (ep->ep_num == ep_num)
612 #define ep_type_name(type) \
613 (type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
616 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
619 * @ep_num: The number of the endpoint to use
620 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
622 * If the requested endpoint has not been added to the given chip before,
623 * a new instance is created.
625 * Returns zero on success or a negative error code.
627 * New endpoints will be added to chip->ep_list and freed by
628 * calling snd_usb_endpoint_free_all().
630 * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
631 * bNumEndpoints > 1 beforehand.
633 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
635 struct snd_usb_endpoint *ep;
638 ep = snd_usb_get_endpoint(chip, ep_num);
642 usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
645 ep = kzalloc(sizeof(*ep), GFP_KERNEL);
650 spin_lock_init(&ep->lock);
653 INIT_LIST_HEAD(&ep->ready_playback_urbs);
654 atomic_set(&ep->submitted_urbs, 0);
656 is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
657 ep_num &= USB_ENDPOINT_NUMBER_MASK;
659 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
661 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
663 list_add_tail(&ep->list, &chip->ep_list);
667 /* Set up syncinterval and maxsyncsize for a sync EP */
668 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
669 struct snd_usb_endpoint *ep)
671 struct usb_host_interface *alts;
672 struct usb_endpoint_descriptor *desc;
674 alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
678 desc = get_endpoint(alts, ep->ep_idx);
679 if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
680 desc->bRefresh >= 1 && desc->bRefresh <= 9)
681 ep->syncinterval = desc->bRefresh;
682 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
683 ep->syncinterval = 1;
684 else if (desc->bInterval >= 1 && desc->bInterval <= 16)
685 ep->syncinterval = desc->bInterval - 1;
687 ep->syncinterval = 3;
689 ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
692 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
693 const struct audioformat *fp,
694 const struct snd_pcm_hw_params *params)
698 if (ep->cur_audiofmt != fp)
700 if (ep->cur_rate != params_rate(params) ||
701 ep->cur_format != params_format(params) ||
702 ep->cur_period_frames != params_period_size(params) ||
703 ep->cur_buffer_periods != params_periods(params))
709 * Check whether the given fp and hw params are compatible with the current
710 * setup of the target EP for implicit feedback sync
712 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
713 struct snd_usb_endpoint *ep,
714 const struct audioformat *fp,
715 const struct snd_pcm_hw_params *params)
719 mutex_lock(&chip->mutex);
720 ret = endpoint_compatible(ep, fp, params);
721 mutex_unlock(&chip->mutex);
726 * snd_usb_endpoint_open: Open the endpoint
728 * Called from hw_params to assign the endpoint to the substream.
729 * It's reference-counted, and only the first opener is allowed to set up
730 * arbitrary parameters. The later opener must be compatible with the
731 * former opened parameters.
732 * The endpoint needs to be closed via snd_usb_endpoint_close() later.
734 * Note that this function doesn't configure the endpoint. The substream
735 * needs to set it up later via snd_usb_endpoint_configure().
737 struct snd_usb_endpoint *
738 snd_usb_endpoint_open(struct snd_usb_audio *chip,
739 const struct audioformat *fp,
740 const struct snd_pcm_hw_params *params,
743 struct snd_usb_endpoint *ep;
744 int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
746 mutex_lock(&chip->mutex);
747 ep = snd_usb_get_endpoint(chip, ep_num);
749 usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
755 ep->iface = fp->sync_iface;
756 ep->altsetting = fp->sync_altsetting;
757 ep->ep_idx = fp->sync_ep_idx;
759 ep->iface = fp->iface;
760 ep->altsetting = fp->altsetting;
761 ep->ep_idx = fp->ep_idx;
763 usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
764 ep_num, ep->iface, ep->altsetting, ep->ep_idx);
766 ep->iface_ref = iface_ref_find(chip, ep->iface);
767 if (!ep->iface_ref) {
772 ep->cur_audiofmt = fp;
773 ep->cur_channels = fp->channels;
774 ep->cur_rate = params_rate(params);
775 ep->cur_format = params_format(params);
776 ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
777 ep->cur_channels / 8;
778 ep->cur_period_frames = params_period_size(params);
779 ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
780 ep->cur_buffer_periods = params_periods(params);
781 ep->cur_clock = fp->clock;
783 if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
784 endpoint_set_syncinterval(chip, ep);
786 ep->implicit_fb_sync = fp->implicit_fb;
787 ep->need_setup = true;
789 usb_audio_dbg(chip, " channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
790 ep->cur_channels, ep->cur_rate,
791 snd_pcm_format_name(ep->cur_format),
792 ep->cur_period_bytes, ep->cur_buffer_periods,
793 ep->implicit_fb_sync);
796 if (WARN_ON(!ep->iface_ref)) {
801 if (!endpoint_compatible(ep, fp, params)) {
802 usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
808 usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
812 if (!ep->iface_ref->opened++)
813 ep->iface_ref->need_setup = true;
818 mutex_unlock(&chip->mutex);
823 * snd_usb_endpoint_set_sync: Link data and sync endpoints
825 * Pass NULL to sync_ep to unlink again
827 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
828 struct snd_usb_endpoint *data_ep,
829 struct snd_usb_endpoint *sync_ep)
831 data_ep->sync_source = sync_ep;
835 * Set data endpoint callbacks and the assigned data stream
837 * Called at PCM trigger and cleanups.
838 * Pass NULL to deactivate each callback.
840 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
841 int (*prepare)(struct snd_usb_substream *subs,
843 bool in_stream_lock),
844 void (*retire)(struct snd_usb_substream *subs,
846 struct snd_usb_substream *data_subs)
848 ep->prepare_data_urb = prepare;
849 ep->retire_data_urb = retire;
851 ep->lowlatency_playback = data_subs->lowlatency_playback;
853 ep->lowlatency_playback = false;
854 WRITE_ONCE(ep->data_subs, data_subs);
857 static int endpoint_set_interface(struct snd_usb_audio *chip,
858 struct snd_usb_endpoint *ep,
861 int altset = set ? ep->altsetting : 0;
864 usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
865 ep->iface, altset, ep->ep_num);
866 err = usb_set_interface(chip->dev, ep->iface, altset);
868 usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
869 ep->iface, altset, err);
873 if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
879 * snd_usb_endpoint_close: Close the endpoint
881 * Unreference the already opened endpoint via snd_usb_endpoint_open().
883 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
884 struct snd_usb_endpoint *ep)
886 mutex_lock(&chip->mutex);
887 usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
888 ep->ep_num, ep->opened);
890 if (!--ep->iface_ref->opened &&
891 !(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
892 endpoint_set_interface(chip, ep, false);
897 ep->cur_audiofmt = NULL;
900 ep->iface_ref = NULL;
901 usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
903 mutex_unlock(&chip->mutex);
906 /* Prepare for suspening EP, called from the main suspend handler */
907 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
909 ep->need_setup = true;
911 ep->iface_ref->need_setup = true;
915 * wait until all urbs are processed.
917 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
919 unsigned long end_time = jiffies + msecs_to_jiffies(1000);
922 if (atomic_read(&ep->state) != EP_STATE_STOPPING)
926 alive = atomic_read(&ep->submitted_urbs);
930 schedule_timeout_uninterruptible(1);
931 } while (time_before(jiffies, end_time));
934 usb_audio_err(ep->chip,
935 "timeout: still %d active urbs on EP #%x\n",
938 if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
939 ep->sync_sink = NULL;
940 snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
946 /* sync the pending stop operation;
947 * this function itself doesn't trigger the stop operation
949 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
958 * This function moves the EP to STOPPING state if it's being RUNNING.
960 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
965 if (!force && atomic_read(&ep->running))
968 if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
971 spin_lock_irqsave(&ep->lock, flags);
972 INIT_LIST_HEAD(&ep->ready_playback_urbs);
973 ep->next_packet_head = 0;
974 ep->next_packet_queued = 0;
975 spin_unlock_irqrestore(&ep->lock, flags);
980 for (i = 0; i < ep->nurbs; i++) {
981 if (test_bit(i, &ep->active_mask)) {
982 if (!test_and_set_bit(i, &ep->unlink_mask)) {
983 struct urb *u = ep->urb[i].urb;
993 * release an endpoint's urbs
995 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
999 /* route incoming urbs to nirvana */
1000 snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1002 /* stop and unlink urbs */
1003 err = stop_urbs(ep, force, false);
1007 wait_clear_urbs(ep);
1009 for (i = 0; i < ep->nurbs; i++)
1010 release_urb_ctx(&ep->urb[i]);
1012 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1013 ep->syncbuf, ep->sync_dma);
1021 * configure a data endpoint
1023 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1025 struct snd_usb_audio *chip = ep->chip;
1026 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1027 unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1028 unsigned int max_urbs, i;
1029 const struct audioformat *fmt = ep->cur_audiofmt;
1030 int frame_bits = ep->cur_frame_bytes * 8;
1031 int tx_length_quirk = (has_tx_length_quirk(chip) &&
1032 usb_pipeout(ep->pipe));
1034 usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1035 ep->ep_num, ep->pipe);
1037 if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1039 * When operating in DSD DOP mode, the size of a sample frame
1040 * in hardware differs from the actual physical format width
1041 * because we need to make room for the DOP markers.
1043 frame_bits += ep->cur_channels << 3;
1046 ep->datainterval = fmt->datainterval;
1047 ep->stride = frame_bits >> 3;
1049 switch (ep->cur_format) {
1050 case SNDRV_PCM_FORMAT_U8:
1051 ep->silence_value = 0x80;
1053 case SNDRV_PCM_FORMAT_DSD_U8:
1054 case SNDRV_PCM_FORMAT_DSD_U16_LE:
1055 case SNDRV_PCM_FORMAT_DSD_U32_LE:
1056 case SNDRV_PCM_FORMAT_DSD_U16_BE:
1057 case SNDRV_PCM_FORMAT_DSD_U32_BE:
1058 ep->silence_value = 0x69;
1061 ep->silence_value = 0;
1064 /* assume max. frequency is 50% higher than nominal */
1065 ep->freqmax = ep->freqn + (ep->freqn >> 1);
1066 /* Round up freqmax to nearest integer in order to calculate maximum
1067 * packet size, which must represent a whole number of frames.
1068 * This is accomplished by adding 0x0.ffff before converting the
1069 * Q16.16 format into integer.
1070 * In order to accurately calculate the maximum packet size when
1071 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1072 * multiply by the data interval prior to rounding. For instance,
1073 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1074 * frames with a data interval of 1, but 11 (10.25) frames with a
1075 * data interval of 2.
1076 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1077 * maximum datainterval value of 3, at USB full speed, higher for
1078 * USB high speed, noting that ep->freqmax is in units of
1079 * frames per packet in Q16.16 format.)
1081 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1083 if (tx_length_quirk)
1084 maxsize += sizeof(__le32); /* Space for length descriptor */
1085 /* but wMaxPacketSize might reduce this */
1086 if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1087 /* whatever fits into a max. size packet */
1088 unsigned int data_maxsize = maxsize = ep->maxpacksize;
1090 if (tx_length_quirk)
1091 /* Need to remove the length descriptor to calc freq */
1092 data_maxsize -= sizeof(__le32);
1093 ep->freqmax = (data_maxsize / (frame_bits >> 3))
1094 << (16 - ep->datainterval);
1098 ep->curpacksize = ep->maxpacksize;
1100 ep->curpacksize = maxsize;
1102 if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1103 packs_per_ms = 8 >> ep->datainterval;
1104 max_packs_per_urb = MAX_PACKS_HS;
1107 max_packs_per_urb = MAX_PACKS;
1109 if (ep->sync_source && !ep->implicit_fb_sync)
1110 max_packs_per_urb = min(max_packs_per_urb,
1111 1U << ep->sync_source->syncinterval);
1112 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1115 * Capture endpoints need to use small URBs because there's no way
1116 * to tell in advance where the next period will end, and we don't
1117 * want the next URB to complete much after the period ends.
1119 * Playback endpoints with implicit sync much use the same parameters
1120 * as their corresponding capture endpoint.
1122 if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1124 urb_packs = packs_per_ms;
1126 * Wireless devices can poll at a max rate of once per 4ms.
1127 * For dataintervals less than 5, increase the packet count to
1128 * allow the host controller to use bursting to fill in the
1131 if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1132 int interval = ep->datainterval;
1133 while (interval < 5) {
1138 /* make capture URBs <= 1 ms and smaller than a period */
1139 urb_packs = min(max_packs_per_urb, urb_packs);
1140 while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1142 ep->nurbs = MAX_URBS;
1145 * Playback endpoints without implicit sync are adjusted so that
1146 * a period fits as evenly as possible in the smallest number of
1147 * URBs. The total number of URBs is adjusted to the size of the
1148 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1151 /* determine how small a packet can be */
1152 minsize = (ep->freqn >> (16 - ep->datainterval)) *
1154 /* with sync from device, assume it can be 12% lower */
1155 if (ep->sync_source)
1156 minsize -= minsize >> 3;
1157 minsize = max(minsize, 1u);
1159 /* how many packets will contain an entire ALSA period? */
1160 max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1162 /* how many URBs will contain a period? */
1163 urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1165 /* how many packets are needed in each URB? */
1166 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1168 /* limit the number of frames in a single URB */
1169 ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1172 /* try to use enough URBs to contain an entire ALSA buffer */
1173 max_urbs = min((unsigned) MAX_URBS,
1174 MAX_QUEUE * packs_per_ms / urb_packs);
1175 ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1178 /* allocate and initialize data urbs */
1179 for (i = 0; i < ep->nurbs; i++) {
1180 struct snd_urb_ctx *u = &ep->urb[i];
1183 u->packets = urb_packs;
1184 u->buffer_size = maxsize * u->packets;
1186 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1187 u->packets++; /* for transfer delimiter */
1188 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1192 u->urb->transfer_buffer =
1193 usb_alloc_coherent(chip->dev, u->buffer_size,
1194 GFP_KERNEL, &u->urb->transfer_dma);
1195 if (!u->urb->transfer_buffer)
1197 u->urb->pipe = ep->pipe;
1198 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1199 u->urb->interval = 1 << ep->datainterval;
1200 u->urb->context = u;
1201 u->urb->complete = snd_complete_urb;
1202 INIT_LIST_HEAD(&u->ready_list);
1208 release_urbs(ep, false);
1213 * configure a sync endpoint
1215 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1217 struct snd_usb_audio *chip = ep->chip;
1220 usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1221 ep->ep_num, ep->pipe);
1223 ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1224 GFP_KERNEL, &ep->sync_dma);
1228 ep->nurbs = SYNC_URBS;
1229 for (i = 0; i < SYNC_URBS; i++) {
1230 struct snd_urb_ctx *u = &ep->urb[i];
1234 u->urb = usb_alloc_urb(1, GFP_KERNEL);
1237 u->urb->transfer_buffer = ep->syncbuf + i * 4;
1238 u->urb->transfer_dma = ep->sync_dma + i * 4;
1239 u->urb->transfer_buffer_length = 4;
1240 u->urb->pipe = ep->pipe;
1241 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1242 u->urb->number_of_packets = 1;
1243 u->urb->interval = 1 << ep->syncinterval;
1244 u->urb->context = u;
1245 u->urb->complete = snd_complete_urb;
1251 release_urbs(ep, false);
1256 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1258 * Determine the number of URBs to be used on this endpoint.
1259 * An endpoint must be configured before it can be started.
1260 * An endpoint that is already running can not be reconfigured.
1262 static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1263 struct snd_usb_endpoint *ep)
1265 const struct audioformat *fmt = ep->cur_audiofmt;
1268 /* release old buffers, if any */
1269 err = release_urbs(ep, false);
1273 ep->datainterval = fmt->datainterval;
1274 ep->maxpacksize = fmt->maxpacksize;
1275 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1277 if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1278 ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1279 ep->pps = 1000 >> ep->datainterval;
1281 ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1282 ep->pps = 8000 >> ep->datainterval;
1285 ep->sample_rem = ep->cur_rate % ep->pps;
1286 ep->packsize[0] = ep->cur_rate / ep->pps;
1287 ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1289 /* calculate the frequency in 16.16 format */
1290 ep->freqm = ep->freqn;
1291 ep->freqshift = INT_MIN;
1296 case SND_USB_ENDPOINT_TYPE_DATA:
1297 err = data_ep_set_params(ep);
1299 case SND_USB_ENDPOINT_TYPE_SYNC:
1300 err = sync_ep_set_params(ep);
1306 usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1311 /* some unit conversions in runtime */
1312 ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1313 ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1319 * snd_usb_endpoint_configure: Configure the endpoint
1321 * This function sets up the EP to be fully usable state.
1322 * It's called either from hw_params or prepare callback.
1323 * The function checks need_setup flag, and performs nothing unless needed,
1324 * so it's safe to call this multiple times.
1326 * This returns zero if unchanged, 1 if the configuration has changed,
1327 * or a negative error code.
1329 int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
1330 struct snd_usb_endpoint *ep)
1335 mutex_lock(&chip->mutex);
1336 if (WARN_ON(!ep->iface_ref))
1338 if (!ep->need_setup)
1341 /* If the interface has been already set up, just set EP parameters */
1342 if (!ep->iface_ref->need_setup) {
1343 /* sample rate setup of UAC1 is per endpoint, and we need
1344 * to update at each EP configuration
1346 if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1347 err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt,
1352 err = snd_usb_endpoint_set_params(chip, ep);
1358 /* Need to deselect altsetting at first */
1359 endpoint_set_interface(chip, ep, false);
1361 /* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1362 * to be set up before parameter setups
1364 iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1365 /* Workaround for devices that require the interface setup at first like UAC1 */
1366 if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1369 err = endpoint_set_interface(chip, ep, true);
1374 err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1378 err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, ep->cur_rate);
1382 err = snd_usb_endpoint_set_params(chip, ep);
1386 err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1390 /* for UAC2/3, enable the interface altset here at last */
1392 err = endpoint_set_interface(chip, ep, true);
1397 ep->iface_ref->need_setup = false;
1400 ep->need_setup = false;
1404 mutex_unlock(&chip->mutex);
1408 /* get the current rate set to the given clock by any endpoint */
1409 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1411 struct snd_usb_endpoint *ep;
1416 mutex_lock(&chip->mutex);
1417 list_for_each_entry(ep, &chip->ep_list, list) {
1418 if (ep->cur_clock == clock && ep->cur_rate) {
1419 rate = ep->cur_rate;
1423 mutex_unlock(&chip->mutex);
1428 * snd_usb_endpoint_start: start an snd_usb_endpoint
1430 * @ep: the endpoint to start
1432 * A call to this function will increment the running count of the endpoint.
1433 * In case it is not already running, the URBs for this endpoint will be
1434 * submitted. Otherwise, this function does nothing.
1436 * Must be balanced to calls of snd_usb_endpoint_stop().
1438 * Returns an error if the URB submission failed, 0 in all other cases.
1440 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1442 bool is_playback = usb_pipeout(ep->pipe);
1446 if (atomic_read(&ep->chip->shutdown))
1449 if (ep->sync_source)
1450 WRITE_ONCE(ep->sync_source->sync_sink, ep);
1452 usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1453 ep_type_name(ep->type), ep->ep_num,
1454 atomic_read(&ep->running));
1456 /* already running? */
1457 if (atomic_inc_return(&ep->running) != 1)
1460 ep->active_mask = 0;
1461 ep->unlink_mask = 0;
1463 ep->sample_accum = 0;
1465 snd_usb_endpoint_start_quirk(ep);
1468 * If this endpoint has a data endpoint as implicit feedback source,
1469 * don't start the urbs here. Instead, mark them all as available,
1470 * wait for the record urbs to return and queue the playback urbs
1471 * from that context.
1474 if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1477 if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1478 !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1479 usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1484 for (i = 0; i < ep->nurbs; i++) {
1485 struct urb *urb = ep->urb[i].urb;
1487 if (snd_BUG_ON(!urb))
1491 err = prepare_outbound_urb(ep, urb->context, true);
1493 err = prepare_inbound_urb(ep, urb->context);
1495 /* stop filling at applptr */
1498 usb_audio_dbg(ep->chip,
1499 "EP 0x%x: failed to prepare urb: %d\n",
1504 err = usb_submit_urb(urb, GFP_ATOMIC);
1506 usb_audio_err(ep->chip,
1507 "cannot submit urb %d, error %d: %s\n",
1508 i, err, usb_error_string(err));
1511 set_bit(i, &ep->active_mask);
1512 atomic_inc(&ep->submitted_urbs);
1516 usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1521 usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1525 /* put the remaining URBs to ready list */
1527 for (; i < ep->nurbs; i++)
1528 push_back_to_ready_list(ep, ep->urb + i);
1534 snd_usb_endpoint_stop(ep, false);
1539 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1541 * @ep: the endpoint to stop (may be NULL)
1542 * @keep_pending: keep in-flight URBs
1544 * A call to this function will decrement the running count of the endpoint.
1545 * In case the last user has requested the endpoint stop, the URBs will
1546 * actually be deactivated.
1548 * Must be balanced to calls of snd_usb_endpoint_start().
1550 * The caller needs to synchronize the pending stop operation via
1551 * snd_usb_endpoint_sync_pending_stop().
1553 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1558 usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1559 ep_type_name(ep->type), ep->ep_num,
1560 atomic_read(&ep->running));
1562 if (snd_BUG_ON(!atomic_read(&ep->running)))
1565 if (!atomic_dec_return(&ep->running)) {
1566 if (ep->sync_source)
1567 WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1568 stop_urbs(ep, false, keep_pending);
1573 * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1575 * @ep: the endpoint to release
1577 * This function does not care for the endpoint's running count but will tear
1578 * down all the streaming URBs immediately.
1580 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1582 release_urbs(ep, true);
1586 * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1589 * This free all endpoints and those resources
1591 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1593 struct snd_usb_endpoint *ep, *en;
1594 struct snd_usb_iface_ref *ip, *in;
1596 list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1599 list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1604 * snd_usb_handle_sync_urb: parse an USB sync packet
1606 * @ep: the endpoint to handle the packet
1607 * @sender: the sending endpoint
1608 * @urb: the received packet
1610 * This function is called from the context of an endpoint that received
1611 * the packet and is used to let another endpoint object handle the payload.
1613 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1614 struct snd_usb_endpoint *sender,
1615 const struct urb *urb)
1619 unsigned long flags;
1621 snd_BUG_ON(ep == sender);
1624 * In case the endpoint is operating in implicit feedback mode, prepare
1625 * a new outbound URB that has the same layout as the received packet
1626 * and add it to the list of pending urbs. queue_pending_output_urbs()
1627 * will take care of them later.
1629 if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1630 atomic_read(&ep->running)) {
1632 /* implicit feedback case */
1634 struct snd_urb_ctx *in_ctx;
1635 struct snd_usb_packet_info *out_packet;
1637 in_ctx = urb->context;
1639 /* Count overall packet size */
1640 for (i = 0; i < in_ctx->packets; i++)
1641 if (urb->iso_frame_desc[i].status == 0)
1642 bytes += urb->iso_frame_desc[i].actual_length;
1645 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1646 * streaming once it received a 0-byte OUT URB
1651 spin_lock_irqsave(&ep->lock, flags);
1652 if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1653 spin_unlock_irqrestore(&ep->lock, flags);
1654 usb_audio_err(ep->chip,
1655 "next package FIFO overflow EP 0x%x\n",
1661 out_packet = next_packet_fifo_enqueue(ep);
1664 * Iterate through the inbound packet and prepare the lengths
1665 * for the output packet. The OUT packet we are about to send
1666 * will have the same amount of payload bytes per stride as the
1667 * IN packet we just received. Since the actual size is scaled
1668 * by the stride, use the sender stride to calculate the length
1669 * in case the number of channels differ between the implicitly
1670 * fed-back endpoint and the synchronizing endpoint.
1673 out_packet->packets = in_ctx->packets;
1674 for (i = 0; i < in_ctx->packets; i++) {
1675 if (urb->iso_frame_desc[i].status == 0)
1676 out_packet->packet_size[i] =
1677 urb->iso_frame_desc[i].actual_length / sender->stride;
1679 out_packet->packet_size[i] = 0;
1682 spin_unlock_irqrestore(&ep->lock, flags);
1683 snd_usb_queue_pending_output_urbs(ep, false);
1689 * process after playback sync complete
1691 * Full speed devices report feedback values in 10.14 format as samples
1692 * per frame, high speed devices in 16.16 format as samples per
1695 * Because the Audio Class 1 spec was written before USB 2.0, many high
1696 * speed devices use a wrong interpretation, some others use an
1697 * entirely different format.
1699 * Therefore, we cannot predict what format any particular device uses
1700 * and must detect it automatically.
1703 if (urb->iso_frame_desc[0].status != 0 ||
1704 urb->iso_frame_desc[0].actual_length < 3)
1707 f = le32_to_cpup(urb->transfer_buffer);
1708 if (urb->iso_frame_desc[0].actual_length == 3)
1716 if (unlikely(sender->tenor_fb_quirk)) {
1718 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1719 * and others) sometimes change the feedback value
1722 if (f < ep->freqn - 0x8000)
1724 else if (f > ep->freqn + 0x8000)
1726 } else if (unlikely(ep->freqshift == INT_MIN)) {
1728 * The first time we see a feedback value, determine its format
1729 * by shifting it left or right until it matches the nominal
1730 * frequency value. This assumes that the feedback does not
1731 * differ from the nominal value more than +50% or -25%.
1734 while (f < ep->freqn - ep->freqn / 4) {
1738 while (f > ep->freqn + ep->freqn / 2) {
1742 ep->freqshift = shift;
1743 } else if (ep->freqshift >= 0)
1744 f <<= ep->freqshift;
1746 f >>= -ep->freqshift;
1748 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1750 * If the frequency looks valid, set it.
1751 * This value is referred to in prepare_playback_urb().
1753 spin_lock_irqsave(&ep->lock, flags);
1755 spin_unlock_irqrestore(&ep->lock, flags);
1758 * Out of range; maybe the shift value is wrong.
1759 * Reset it so that we autodetect again the next time.
1761 ep->freqshift = INT_MIN;