6 files changed, 385 insertions, 119 deletions

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 6bc88b7ce4f..d5b5c3388e2 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -131,8 +131,9 @@ static void snd_usb_stream_disconnect(struct list_head *head)
                 subs = &as->substream[idx];
                 if (!subs->num_formats)
                         continue;
-                snd_usb_release_substream_urbs(subs, 1);
                 subs->interface = -1;
+                subs->data_endpoint = NULL;
+                subs->sync_endpoint = NULL;
         }
 }
 
@@ -350,6 +351,7 @@ static int snd_usb_audio_create(struct usb_device *dev, int idx,
         chip->usb_id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
                               le16_to_cpu(dev->descriptor.idProduct));
         INIT_LIST_HEAD(&chip->pcm_list);
+        INIT_LIST_HEAD(&chip->ep_list);
         INIT_LIST_HEAD(&chip->midi_list);
         INIT_LIST_HEAD(&chip->mixer_list);
 
@@ -567,6 +569,10 @@ static void snd_usb_audio_disconnect(struct usb_device *dev,
                 list_for_each(p, &chip->pcm_list) {
                         snd_usb_stream_disconnect(p);
                 }
+                /* release the endpoint resources */
+                list_for_each(p, &chip->ep_list) {
+                        snd_usb_endpoint_free(p);
+                }
                 /* release the midi resources */
                 list_for_each(p, &chip->midi_list) {
                         snd_usbmidi_disconnect(p);
diff --git a/sound/usb/card.h b/sound/usb/card.h
index 9acbd4a1228..8a08687e5bc 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -145,6 +145,10 @@ struct snd_usb_substream {
         struct snd_urb_ctx syncurb[SYNC_URBS];  /* sync urb table */
         char *syncbuf;                          /* sync buffer for all sync URBs */
         dma_addr_t sync_dma;                    /* DMA address of syncbuf */
+        /* data and sync endpoints for this stream */
+        struct snd_usb_endpoint *data_endpoint;
+        struct snd_usb_endpoint *sync_endpoint;
+        unsigned long flags;
 
         u64 formats;                    /* format bitmasks (all or'ed) */
         unsigned int num_formats;               /* number of supported audio formats (list) */
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index ea25265427a..1b0ed22cff7 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -912,46 +912,6 @@ void snd_usb_init_substream(struct snd_usb_stream *as,
         subs->fmt_type = fp->fmt_type;
 }
 
-int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream, int cmd)
-{
-        struct snd_usb_substream *subs = substream->runtime->private_data;
-
-        switch (cmd) {
-        case SNDRV_PCM_TRIGGER_START:
-        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-                subs->ops.prepare = prepare_playback_urb;
-                return 0;
-        case SNDRV_PCM_TRIGGER_STOP:
-                return deactivate_urbs_old(subs, 0, 0);
-        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
-                subs->ops.prepare = prepare_nodata_playback_urb;
-                return 0;
-        }
-
-        return -EINVAL;
-}
-
-int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int cmd)
-{
-        struct snd_usb_substream *subs = substream->runtime->private_data;
-
-        switch (cmd) {
-        case SNDRV_PCM_TRIGGER_START:
-                subs->ops.retire = retire_capture_urb;
-                return start_urbs(subs, substream->runtime);
-        case SNDRV_PCM_TRIGGER_STOP:
-                return deactivate_urbs_old(subs, 0, 0);
-        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
-                subs->ops.retire = retire_paused_capture_urb;
-                return 0;
-        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-                subs->ops.retire = retire_capture_urb;
-                return 0;
-        }
-
-        return -EINVAL;
-}
-
 int snd_usb_substream_prepare(struct snd_usb_substream *subs,
                               struct snd_pcm_runtime *runtime)
 {
diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
index 9f083d7d6cf..e540768de3d 100644
--- a/sound/usb/endpoint.h
+++ b/sound/usb/endpoint.h
@@ -15,9 +15,6 @@ void snd_usb_release_substream_urbs(struct snd_usb_substream *subs, int force);
 int snd_usb_substream_prepare(struct snd_usb_substream *subs,
                               struct snd_pcm_runtime *runtime);
 
-int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream, int cmd);
-int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int cmd);
-
 
 #define SND_USB_ENDPOINT_TYPE_DATA     0
 #define SND_USB_ENDPOINT_TYPE_SYNC     1
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 0eed6115c2d..0f107834c10 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -16,6 +16,7 @@
 
 #include <linux/init.h>
 #include <linux/slab.h>
+#include <linux/ratelimit.h>
 #include <linux/usb.h>
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
@@ -34,6 +35,9 @@
 #include "clock.h"
 #include "power.h"
 
+#define SUBSTREAM_FLAG_DATA_EP_STARTED  0
+#define SUBSTREAM_FLAG_SYNC_EP_STARTED  1
+
 /* return the estimated delay based on USB frame counters */
 snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
                                     unsigned int rate)
@@ -208,6 +212,84 @@ int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
         }
 }
 
+static int start_endpoints(struct snd_usb_substream *subs)
+{
+        int err;
+
+        if (!subs->data_endpoint)
+                return -EINVAL;
+
+        if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
+                struct snd_usb_endpoint *ep = subs->data_endpoint;
+
+                snd_printdd(KERN_DEBUG "Starting data EP @%p\n", ep);
+
+                ep->data_subs = subs;
+                err = snd_usb_endpoint_start(ep);
+                if (err < 0) {
+                        clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
+                        return err;
+                }
+        }
+
+        if (subs->sync_endpoint &&
+            !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
+                struct snd_usb_endpoint *ep = subs->sync_endpoint;
+
+                snd_printdd(KERN_DEBUG "Starting sync EP @%p\n", ep);
+
+                ep->sync_slave = subs->data_endpoint;
+                err = snd_usb_endpoint_start(ep);
+                if (err < 0) {
+                        clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
+                        return err;
+                }
+        }
+
+        return 0;
+}
+
+static void stop_endpoints(struct snd_usb_substream *subs,
+                           int force, int can_sleep, int wait)
+{
+        if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags))
+                snd_usb_endpoint_stop(subs->sync_endpoint,
+                                      force, can_sleep, wait);
+
+        if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags))
+                snd_usb_endpoint_stop(subs->data_endpoint,
+                                      force, can_sleep, wait);
+}
+
+static int activate_endpoints(struct snd_usb_substream *subs)
+{
+        if (subs->sync_endpoint) {
+                int ret;
+
+                ret = snd_usb_endpoint_activate(subs->sync_endpoint);
+                if (ret < 0)
+                        return ret;
+        }
+
+        return snd_usb_endpoint_activate(subs->data_endpoint);
+}
+
+static int deactivate_endpoints(struct snd_usb_substream *subs)
+{
+        int reta, retb;
+
+        reta = snd_usb_endpoint_deactivate(subs->sync_endpoint);
+        retb = snd_usb_endpoint_deactivate(subs->data_endpoint);
+
+        if (reta < 0)
+                return reta;
+
+        if (retb < 0)
+                return retb;
+
+        return 0;
+}
+
 /*
  * find a matching format and set up the interface
  */
@@ -232,40 +314,11 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
         if (fmt == subs->cur_audiofmt)
                 return 0;
 
-        /* close the old interface */
-        if (subs->interface >= 0 && subs->interface != fmt->iface) {
-                if (usb_set_interface(subs->dev, subs->interface, 0) < 0) {
-                        snd_printk(KERN_ERR "%d:%d:%d: return to setting 0 failed\n",
-                                dev->devnum, fmt->iface, fmt->altsetting);
-                        return -EIO;
-                }
-                subs->interface = -1;
-                subs->altset_idx = 0;
-        }
-
-        /* set interface */
-        if (subs->interface != fmt->iface || subs->altset_idx != 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->altset_idx = 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);
-        subs->datainterval = fmt->datainterval;
-        subs->syncpipe = subs->syncinterval = 0;
-        subs->maxpacksize = fmt->maxpacksize;
-        subs->syncmaxsize = 0;
-        subs->fill_max = 0;
+        subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
+                                                   alts, fmt->endpoint, subs->direction,
+                                                   SND_USB_ENDPOINT_TYPE_DATA);
+        if (!subs->data_endpoint)
+                return -EINVAL;
 
         /* we need a sync pipe in async OUT or adaptive IN mode */
         /* check the number of EP, since some devices have broken
@@ -276,6 +329,15 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
         if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
              (! is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&
             altsd->bNumEndpoints >= 2) {
+                switch (subs->stream->chip->usb_id) {
+                case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
+                case USB_ID(0x0763, 0x2081):
+                        ep = 0x81;
+                        iface = usb_ifnum_to_if(dev, 2);
+                        alts = &iface->altsetting[1];
+                        goto add_sync_ep;
+                }
+
                 /* check sync-pipe endpoint */
                 /* ... and check descriptor size before accessing bSynchAddress
                    because there is a version of the SB Audigy 2 NX firmware lacking
@@ -295,28 +357,16 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
                                    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;
-                subs->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
-        }
-
-        /* always fill max packet size */
-        if (fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX)
-                subs->fill_max = 1;
+add_sync_ep:
+                subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
+                                                           alts, ep, !subs->direction,
+                                                           SND_USB_ENDPOINT_TYPE_SYNC);
+
+                if (!subs->sync_endpoint)
+                        return -EINVAL;
+
+                subs->data_endpoint->sync_master = subs->sync_endpoint;
+        }
 
         if ((err = snd_usb_init_pitch(subs->stream->chip, subs->interface, alts, fmt)) < 0)
                 return err;
@@ -390,12 +440,22 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
         if (changed) {
                 mutex_lock(&subs->stream->chip->shutdown_mutex);
                 /* format changed */
-                snd_usb_release_substream_urbs(subs, 0);
-                /* influenced: period_bytes, channels, rate, format, */
-                ret = snd_usb_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));
+                stop_endpoints(subs, 0, 0, 0);
+                deactivate_endpoints(subs);
+
+                ret = activate_endpoints(subs);
+                if (ret < 0)
+                        goto unlock;
+
+                ret = snd_usb_endpoint_set_params(subs->data_endpoint, hw_params, fmt,
+                                                  subs->sync_endpoint);
+                if (ret < 0)
+                        goto unlock;
+
+                if (subs->sync_endpoint)
+                        ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
+                                                          hw_params, fmt, NULL);
+unlock:
                 mutex_unlock(&subs->stream->chip->shutdown_mutex);
         }
 
@@ -415,7 +475,7 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
         subs->cur_rate = 0;
         subs->period_bytes = 0;
         mutex_lock(&subs->stream->chip->shutdown_mutex);
-        snd_usb_release_substream_urbs(subs, 0);
+        stop_endpoints(subs, 0, 1, 1);
         mutex_unlock(&subs->stream->chip->shutdown_mutex);
         return snd_pcm_lib_free_vmalloc_buffer(substream);
 }
@@ -435,19 +495,28 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
                 return -ENXIO;
         }
 
+        if (snd_BUG_ON(!subs->data_endpoint))
+                return -EIO;
+
         /* some unit conversions in runtime */
-        subs->maxframesize = bytes_to_frames(runtime, subs->maxpacksize);
-        subs->curframesize = bytes_to_frames(runtime, subs->curpacksize);
+        subs->data_endpoint->maxframesize =
+                bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
+        subs->data_endpoint->curframesize =
+                bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
 
         /* reset the pointer */
         subs->hwptr_done = 0;
         subs->transfer_done = 0;
-        subs->phase = 0;
         subs->last_delay = 0;
         subs->last_frame_number = 0;
         runtime->delay = 0;
 
-        return snd_usb_substream_prepare(subs, runtime);
+        /* for playback, submit the URBs now; otherwise, the first hwptr_done
+         * updates for all URBs would happen at the same time when starting */
+        if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
+                return start_endpoints(subs);
+
+        return 0;
 }
 
 static struct snd_pcm_hardware snd_usb_hardware =
@@ -842,16 +911,171 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
 
 static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
 {
+        int ret;
         struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
         struct snd_usb_substream *subs = &as->substream[direction];
 
-        if (!as->chip->shutdown && subs->interface >= 0) {
-                usb_set_interface(subs->dev, subs->interface, 0);
-                subs->interface = -1;
-        }
+        stop_endpoints(subs, 0, 0, 0);
+        ret = deactivate_endpoints(subs);
         subs->pcm_substream = NULL;
         snd_usb_autosuspend(subs->stream->chip);
-        return 0;
+
+        return ret;
+}
+
+/* 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 void retire_capture_urb(struct snd_usb_substream *subs,
+                               struct urb *urb)
+{
+        struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+        unsigned int stride, frames, bytes, oldptr;
+        int i, period_elapsed = 0;
+        unsigned long flags;
+        unsigned char *cp;
+
+        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 && printk_ratelimit()) {
+                        snd_printdd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
+                        // continue;
+                }
+                bytes = urb->iso_frame_desc[i].actual_length;
+                frames = bytes / stride;
+                if (!subs->txfr_quirk)
+                        bytes = frames * stride;
+                if (bytes % (runtime->sample_bits >> 3) != 0) {
+#ifdef CONFIG_SND_DEBUG_VERBOSE
+                        int oldbytes = bytes;
+#endif
+                        bytes = frames * stride;
+                        snd_printdd(KERN_ERR "Corrected urb data len. %d->%d\n",
+                                                        oldbytes, bytes);
+                }
+                /* update the current pointer */
+                spin_lock_irqsave(&subs->lock, flags);
+                oldptr = subs->hwptr_done;
+                subs->hwptr_done += bytes;
+                if (subs->hwptr_done >= runtime->buffer_size * stride)
+                        subs->hwptr_done -= runtime->buffer_size * stride;
+                frames = (bytes + (oldptr % stride)) / stride;
+                subs->transfer_done += frames;
+                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 + bytes > runtime->buffer_size * stride) {
+                        unsigned int bytes1 =
+                                        runtime->buffer_size * stride - oldptr;
+                        memcpy(runtime->dma_area + oldptr, cp, bytes1);
+                        memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
+                } else {
+                        memcpy(runtime->dma_area + oldptr, cp, bytes);
+                }
+        }
+
+        if (period_elapsed)
+                snd_pcm_period_elapsed(subs->pcm_substream);
+}
+
+static void prepare_playback_urb(struct snd_usb_substream *subs,
+                                 struct urb *urb)
+{
+        struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+        struct snd_urb_ctx *ctx = urb->context;
+        unsigned int counts, frames, bytes;
+        int i, stride, period_elapsed = 0;
+        unsigned long flags;
+
+        stride = runtime->frame_bits >> 3;
+
+        frames = 0;
+        urb->number_of_packets = 0;
+        spin_lock_irqsave(&subs->lock, flags);
+        for (i = 0; i < ctx->packets; i++) {
+                counts = ctx->packet_size[i];
+                /* set up descriptor */
+                urb->iso_frame_desc[i].offset = frames * stride;
+                urb->iso_frame_desc[i].length = counts * stride;
+                frames += 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 == UAC_FORMAT_TYPE_II) {
+                                if (subs->transfer_done > 0) {
+                                        /* FIXME: fill-max mode is not
+                                         * supported yet */
+                                        frames -= 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 =
+                                                frames * stride;
+                                        urb->iso_frame_desc[i].length = 0;
+                                        urb->number_of_packets++;
+                                }
+                                break;
+                        }
+                }
+                if (period_elapsed &&
+                    !snd_usb_endpoint_implict_feedback_sink(subs->data_endpoint)) /* finish at the period boundary */
+                        break;
+        }
+        bytes = frames * stride;
+        if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
+                /* err, the transferred area goes over buffer boundary. */
+                unsigned int bytes1 =
+                        runtime->buffer_size * stride - subs->hwptr_done;
+                memcpy(urb->transfer_buffer,
+                       runtime->dma_area + subs->hwptr_done, bytes1);
+                memcpy(urb->transfer_buffer + bytes1,
+                       runtime->dma_area, bytes - bytes1);
+        } else {
+                memcpy(urb->transfer_buffer,
+                       runtime->dma_area + subs->hwptr_done, bytes);
+        }
+        subs->hwptr_done += bytes;
+        if (subs->hwptr_done >= runtime->buffer_size * stride)
+                subs->hwptr_done -= runtime->buffer_size * stride;
+        runtime->delay += frames;
+        spin_unlock_irqrestore(&subs->lock, flags);
+        urb->transfer_buffer_length = bytes;
+        if (period_elapsed)
+                snd_pcm_period_elapsed(subs->pcm_substream);
+}
+
+/*
+ * process after playback data complete
+ * - decrease the delay count again
+ */
+static void retire_playback_urb(struct snd_usb_substream *subs,
+                               struct urb *urb)
+{
+        unsigned long flags;
+        struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+        int stride = runtime->frame_bits >> 3;
+        int processed = urb->transfer_buffer_length / stride;
+
+        spin_lock_irqsave(&subs->lock, flags);
+        if (processed > runtime->delay)
+                runtime->delay = 0;
+        else
+                runtime->delay -= processed;
+        spin_unlock_irqrestore(&subs->lock, flags);
 }
 
 static int snd_usb_playback_open(struct snd_pcm_substream *substream)
@@ -874,6 +1098,56 @@ static int snd_usb_capture_close(struct snd_pcm_substream *substream)
         return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_CAPTURE);
 }
 
+static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
+                                              int cmd)
+{
+        struct snd_usb_substream *subs = substream->runtime->private_data;
+
+        switch (cmd) {
+        case SNDRV_PCM_TRIGGER_START:
+        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+                subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
+                subs->data_endpoint->retire_data_urb = retire_playback_urb;
+                return 0;
+        case SNDRV_PCM_TRIGGER_STOP:
+                stop_endpoints(subs, 0, 0, 0);
+                return 0;
+        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+                subs->data_endpoint->prepare_data_urb = NULL;
+                subs->data_endpoint->retire_data_urb = NULL;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+        int err;
+        struct snd_usb_substream *subs = substream->runtime->private_data;
+
+        switch (cmd) {
+        case SNDRV_PCM_TRIGGER_START:
+                err = start_endpoints(subs);
+                if (err < 0)
+                        return err;
+
+                subs->data_endpoint->retire_data_urb = retire_capture_urb;
+                return 0;
+        case SNDRV_PCM_TRIGGER_STOP:
+                stop_endpoints(subs, 0, 0, 0);
+                return 0;
+        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+                subs->data_endpoint->retire_data_urb = NULL;
+                return 0;
+        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+                subs->data_endpoint->retire_data_urb = retire_capture_urb;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
 static struct snd_pcm_ops snd_usb_playback_ops = {
         .open =         snd_usb_playback_open,
         .close =        snd_usb_playback_close,
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 5ff8010b2d6..6b7d7a2b7ba 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -73,6 +73,31 @@ static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
         }
 }
 
+/*
+ * initialize the substream instance.
+ */
+
+static void snd_usb_init_substream(struct snd_usb_stream *as,
+                                   int stream,
+                                   struct audioformat *fp)
+{
+        struct snd_usb_substream *subs = &as->substream[stream];
+
+        INIT_LIST_HEAD(&subs->fmt_list);
+        spin_lock_init(&subs->lock);
+
+        subs->stream = as;
+        subs->direction = stream;
+        subs->dev = as->chip->dev;
+        subs->txfr_quirk = as->chip->txfr_quirk;
+
+        snd_usb_set_pcm_ops(as->pcm, stream);
+
+        list_add_tail(&fp->list, &subs->fmt_list);
+        subs->formats |= fp->formats;
+        subs->num_formats++;
+        subs->fmt_type = fp->fmt_type;
+}
 
 /*
  * add this endpoint to the chip instance.
@@ -94,9 +119,9 @@ int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
                 if (as->fmt_type != fp->fmt_type)
                         continue;
                 subs = &as->substream[stream];
-                if (!subs->endpoint)
+                if (!subs->data_endpoint)
                         continue;
-                if (subs->endpoint == fp->endpoint) {
+                if (subs->data_endpoint->ep_num == fp->endpoint) {
                         list_add_tail(&fp->list, &subs->fmt_list);
                         subs->num_formats++;
                         subs->formats |= fp->formats;
@@ -109,7 +134,7 @@ int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
                 if (as->fmt_type != fp->fmt_type)
                         continue;
                 subs = &as->substream[stream];
-                if (subs->endpoint)
+                if (subs->data_endpoint)
                         continue;
                 err = snd_pcm_new_stream(as->pcm, stream, 1);
                 if (err < 0)