diff --git a/sound/usb/card.h b/sound/usb/card.h
index a00caa1db37e..87f042d06ce0 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -74,8 +74,9 @@ struct snd_usb_endpoint {
atomic_t state; /* running state */
- void (*prepare_data_urb) (struct snd_usb_substream *subs,
- struct urb *urb);
+ int (*prepare_data_urb) (struct snd_usb_substream *subs,
+ struct urb *urb,
+ bool in_stream_lock);
void (*retire_data_urb) (struct snd_usb_substream *subs,
struct urb *urb);
@@ -94,7 +95,6 @@ struct snd_usb_endpoint {
struct list_head ready_playback_urbs; /* playback URB FIFO for implicit fb */
unsigned int nurbs; /* # urbs */
- unsigned int nominal_queue_size; /* total buffer sizes in URBs */
unsigned long active_mask; /* bitmask of active urbs */
unsigned long unlink_mask; /* bitmask of unlinked urbs */
atomic_t submitted_urbs; /* currently submitted urbs */
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index c32022672319..0b336876e36d 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -307,8 +307,9 @@ static void prepare_silent_urb(struct snd_usb_endpoint *ep,
/*
* Prepare a PLAYBACK urb for submission to the bus.
*/
-static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
- struct snd_urb_ctx *ctx)
+static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
+ struct snd_urb_ctx *ctx,
+ bool in_stream_lock)
{
struct urb *urb = ctx->urb;
unsigned char *cp = urb->transfer_buffer;
@@ -320,9 +321,9 @@ static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
case SND_USB_ENDPOINT_TYPE_DATA:
data_subs = READ_ONCE(ep->data_subs);
if (data_subs && ep->prepare_data_urb)
- ep->prepare_data_urb(data_subs, urb);
- else /* no data provider, so send silence */
- prepare_silent_urb(ep, ctx);
+ return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
+ /* no data provider, so send silence */
+ prepare_silent_urb(ep, ctx);
break;
case SND_USB_ENDPOINT_TYPE_SYNC:
@@ -351,13 +352,14 @@ static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
break;
}
+ return 0;
}
/*
* Prepare a CAPTURE or SYNC urb for submission to the bus.
*/
-static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
- struct snd_urb_ctx *urb_ctx)
+static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
+ struct snd_urb_ctx *urb_ctx)
{
int i, offs;
struct urb *urb = urb_ctx->urb;
@@ -382,6 +384,7 @@ static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
urb->iso_frame_desc[0].offset = 0;
break;
}
+ return 0;
}
/* notify an error as XRUN to the assigned PCM data substream */
@@ -417,6 +420,16 @@ next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
return p;
}
+static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
+ struct snd_urb_ctx *ctx)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ep->lock, flags);
+ list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
+ spin_unlock_irqrestore(&ep->lock, flags);
+}
+
/*
* Send output urbs that have been prepared previously. URBs are dequeued
* from ep->ready_playback_urbs and in case there aren't any available
@@ -427,12 +440,14 @@ next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
* is that host controllers don't guarantee the order in which they return
* inbound and outbound packets to their submitters.
*
- * This function is only used for implicit feedback endpoints. For endpoints
- * driven by dedicated sync endpoints, URBs are immediately re-submitted
- * from their completion handler.
+ * This function is used both for implicit feedback endpoints and in low-
+ * latency playback mode.
*/
-static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
+void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
+ bool in_stream_lock)
{
+ bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
+
while (ep_state_running(ep)) {
unsigned long flags;
@@ -441,14 +456,14 @@ static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
int err, i;
spin_lock_irqsave(&ep->lock, flags);
- if (ep->next_packet_queued > 0 &&
+ if ((!implicit_fb || ep->next_packet_queued > 0) &&
!list_empty(&ep->ready_playback_urbs)) {
/* take URB out of FIFO */
ctx = list_first_entry(&ep->ready_playback_urbs,
struct snd_urb_ctx, ready_list);
list_del_init(&ctx->ready_list);
-
- packet = next_packet_fifo_dequeue(ep);
+ if (implicit_fb)
+ packet = next_packet_fifo_dequeue(ep);
}
spin_unlock_irqrestore(&ep->lock, flags);
@@ -456,11 +471,24 @@ static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
return;
/* copy over the length information */
- for (i = 0; i < packet->packets; i++)
- ctx->packet_size[i] = packet->packet_size[i];
+ if (implicit_fb) {
+ for (i = 0; i < packet->packets; i++)
+ ctx->packet_size[i] = packet->packet_size[i];
+ }
/* call the data handler to fill in playback data */
- prepare_outbound_urb(ep, ctx);
+ err = prepare_outbound_urb(ep, ctx, in_stream_lock);
+ /* can be stopped during prepare callback */
+ if (unlikely(!ep_state_running(ep)))
+ break;
+ if (err < 0) {
+ /* push back to ready list again for -EAGAIN */
+ if (err == -EAGAIN)
+ push_back_to_ready_list(ep, ctx);
+ else
+ notify_xrun(ep);
+ return;
+ }
err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
if (err < 0) {
@@ -483,7 +511,6 @@ static void snd_complete_urb(struct urb *urb)
{
struct snd_urb_ctx *ctx = urb->context;
struct snd_usb_endpoint *ep = ctx->ep;
- unsigned long flags;
int err;
if (unlikely(urb->status == -ENOENT || /* unlinked */
@@ -504,17 +531,20 @@ static void snd_complete_urb(struct urb *urb)
if (unlikely(!ep_state_running(ep)))
goto exit_clear;
- if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
- spin_lock_irqsave(&ep->lock, flags);
- list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
+ /* in low-latency and implicit-feedback modes, push back the
+ * URB to ready list at first, then process as much as possible
+ */
+ if (ep->lowlatency_playback ||
+ snd_usb_endpoint_implicit_feedback_sink(ep)) {
+ push_back_to_ready_list(ep, ctx);
clear_bit(ctx->index, &ep->active_mask);
- spin_unlock_irqrestore(&ep->lock, flags);
- queue_pending_output_urbs(ep);
+ snd_usb_queue_pending_output_urbs(ep, false);
atomic_dec(&ep->submitted_urbs); /* decrement at last */
return;
}
- prepare_outbound_urb(ep, ctx);
+ /* in non-lowlatency mode, no error handling for prepare */
+ prepare_outbound_urb(ep, ctx, false);
/* can be stopped during prepare callback */
if (unlikely(!ep_state_running(ep)))
goto exit_clear;
@@ -807,8 +837,9 @@ void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
* Pass NULL to deactivate each callback.
*/
void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
- void (*prepare)(struct snd_usb_substream *subs,
- struct urb *urb),
+ int (*prepare)(struct snd_usb_substream *subs,
+ struct urb *urb,
+ bool in_stream_lock),
void (*retire)(struct snd_usb_substream *subs,
struct urb *urb),
struct snd_usb_substream *data_subs)
@@ -1166,10 +1197,6 @@ static int data_ep_set_params(struct snd_usb_endpoint *ep)
INIT_LIST_HEAD(&u->ready_list);
}
- /* total buffer bytes of all URBs plus the next queue;
- * referred in pcm.c
- */
- ep->nominal_queue_size = maxsize * urb_packs * (ep->nurbs + 1);
return 0;
out_of_memory:
@@ -1408,6 +1435,7 @@ int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
*/
int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
{
+ bool is_playback = usb_pipeout(ep->pipe);
int err;
unsigned int i;
@@ -1444,13 +1472,9 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
!(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
- for (i = 0; i < ep->nurbs; i++) {
- struct snd_urb_ctx *ctx = ep->urb + i;
- list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
- }
-
usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
- return 0;
+ i = 0;
+ goto fill_rest;
}
for (i = 0; i < ep->nurbs; i++) {
@@ -1459,10 +1483,18 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
if (snd_BUG_ON(!urb))
goto __error;
- if (usb_pipeout(ep->pipe)) {
- prepare_outbound_urb(ep, urb->context);
- } else {
- prepare_inbound_urb(ep, urb->context);
+ if (is_playback)
+ err = prepare_outbound_urb(ep, urb->context, true);
+ else
+ err = prepare_inbound_urb(ep, urb->context);
+ if (err < 0) {
+ /* stop filling at applptr */
+ if (err == -EAGAIN)
+ break;
+ usb_audio_dbg(ep->chip,
+ "EP 0x%x: failed to prepare urb: %d\n",
+ ep->ep_num, err);
+ goto __error;
}
err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -1476,8 +1508,22 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
atomic_inc(&ep->submitted_urbs);
}
+ if (!i) {
+ usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
+ ep->ep_num);
+ goto __error;
+ }
+
usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
- ep->nurbs, ep->ep_num);
+ i, ep->ep_num);
+
+ fill_rest:
+ /* put the remaining URBs to ready list */
+ if (is_playback) {
+ for (; i < ep->nurbs; i++)
+ push_back_to_ready_list(ep, ep->urb + i);
+ }
+
return 0;
__error:
@@ -1629,7 +1675,7 @@ static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
}
spin_unlock_irqrestore(&ep->lock, flags);
- queue_pending_output_urbs(ep);
+ snd_usb_queue_pending_output_urbs(ep, false);
return;
}
diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
index 1f1a72535a64..6895d50d14d1 100644
--- a/sound/usb/endpoint.h
+++ b/sound/usb/endpoint.h
@@ -30,8 +30,9 @@ void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
struct snd_usb_endpoint *data_ep,
struct snd_usb_endpoint *sync_ep);
void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
- void (*prepare)(struct snd_usb_substream *subs,
- struct urb *urb),
+ int (*prepare)(struct snd_usb_substream *subs,
+ struct urb *urb,
+ bool in_stream_lock),
void (*retire)(struct snd_usb_substream *subs,
struct urb *urb),
struct snd_usb_substream *data_subs);
@@ -48,5 +49,7 @@ int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
struct snd_urb_ctx *ctx, int idx,
unsigned int avail);
+void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
+ bool in_stream_lock);
#endif /* __USBAUDIO_ENDPOINT_H */
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 8ad48c35c559..d5a14e5b9ad3 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -598,9 +598,6 @@ static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
/* implicit feedback mode has own operation mode */
if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
return false;
- /* too short periods? */
- if (subs->data_endpoint->nominal_queue_size >= subs->buffer_bytes)
- return false;
return true;
}
@@ -1095,6 +1092,10 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
int ret;
runtime->hw = snd_usb_hardware;
+ /* need an explicit sync to catch applptr update in low-latency mode */
+ if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
+ as->chip->lowlatency)
+ runtime->hw.info |= SNDRV_PCM_INFO_EXPLICIT_SYNC;
runtime->private_data = subs;
subs->pcm_substream = substream;
/* runtime PM is also done there */
@@ -1347,44 +1348,66 @@ static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
return bytes;
}
-static void prepare_playback_urb(struct snd_usb_substream *subs,
- struct urb *urb)
+static int prepare_playback_urb(struct snd_usb_substream *subs,
+ struct urb *urb,
+ bool in_stream_lock)
{
struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
struct snd_usb_endpoint *ep = subs->data_endpoint;
struct snd_urb_ctx *ctx = urb->context;
- unsigned int counts, frames, bytes;
+ unsigned int frames, bytes;
+ int counts;
+ unsigned int transfer_done, frame_limit, avail = 0;
int i, stride, period_elapsed = 0;
unsigned long flags;
+ int err = 0;
stride = ep->stride;
frames = 0;
ctx->queued = 0;
urb->number_of_packets = 0;
+
spin_lock_irqsave(&subs->lock, flags);
- subs->frame_limit += ep->max_urb_frames;
+ frame_limit = subs->frame_limit + ep->max_urb_frames;
+ transfer_done = subs->transfer_done;
+
+ if (subs->lowlatency_playback &&
+ runtime->status->state != SNDRV_PCM_STATE_DRAINING) {
+ unsigned int hwptr = subs->hwptr_done / stride;
+
+ /* calculate the byte offset-in-buffer of the appl_ptr */
+ avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
+ % runtime->buffer_size;
+ if (avail <= hwptr)
+ avail += runtime->buffer_size;
+ avail -= hwptr;
+ }
+
for (i = 0; i < ctx->packets; i++) {
- counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
+ counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
+ if (counts < 0)
+ break;
/* set up descriptor */
urb->iso_frame_desc[i].offset = frames * stride;
urb->iso_frame_desc[i].length = counts * stride;
frames += counts;
+ avail -= counts;
urb->number_of_packets++;
- subs->transfer_done += counts;
- if (subs->transfer_done >= runtime->period_size) {
- subs->transfer_done -= runtime->period_size;
- subs->frame_limit = 0;
+ transfer_done += counts;
+ if (transfer_done >= runtime->period_size) {
+ transfer_done -= runtime->period_size;
+ frame_limit = 0;
period_elapsed = 1;
if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
- if (subs->transfer_done > 0) {
+ if (transfer_done > 0) {
/* FIXME: fill-max mode is not
* supported yet */
- frames -= subs->transfer_done;
- counts -= subs->transfer_done;
+ frames -= transfer_done;
+ counts -= transfer_done;
urb->iso_frame_desc[i].length =
counts * stride;
- subs->transfer_done = 0;
+ transfer_done = 0;
}
i++;
if (i < ctx->packets) {
@@ -1398,13 +1421,19 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
}
}
/* finish at the period boundary or after enough frames */
- if ((period_elapsed ||
- subs->transfer_done >= subs->frame_limit) &&
+ if ((period_elapsed || transfer_done >= frame_limit) &&
!snd_usb_endpoint_implicit_feedback_sink(ep))
break;
}
- bytes = frames * stride;
+ if (!frames) {
+ err = -EAGAIN;
+ goto unlock;
+ }
+
+ bytes = frames * stride;
+ subs->transfer_done = transfer_done;
+ subs->frame_limit = frame_limit;
if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
subs->cur_audiofmt->dsd_dop)) {
fill_playback_urb_dsd_dop(subs, urb, bytes);
@@ -1434,10 +1463,19 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
subs->period_elapsed_pending = 1;
period_elapsed = 0;
}
+
+ unlock:
spin_unlock_irqrestore(&subs->lock, flags);
+ if (err < 0)
+ return err;
urb->transfer_buffer_length = bytes;
- if (period_elapsed)
- snd_pcm_period_elapsed(subs->pcm_substream);
+ if (period_elapsed) {
+ if (in_stream_lock)
+ snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
+ else
+ snd_pcm_period_elapsed(subs->pcm_substream);
+ }
+ return 0;
}
/*
@@ -1469,6 +1507,27 @@ static void retire_playback_urb(struct snd_usb_substream *subs,
snd_pcm_period_elapsed(subs->pcm_substream);
}
+/* PCM ack callback for the playback stream;
+ * this plays a role only when the stream is running in low-latency mode.
+ */
+static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
+{
+ struct snd_usb_substream *subs = substream->runtime->private_data;
+ struct snd_usb_endpoint *ep;
+
+ if (!subs->lowlatency_playback || !subs->running)
+ return 0;
+ ep = subs->data_endpoint;
+ if (!ep)
+ return 0;
+ /* When no more in-flight URBs available, try to process the pending
+ * outputs here
+ */
+ if (!ep->active_mask)
+ snd_usb_queue_pending_output_urbs(ep, true);
+ return 0;
+}
+
static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
int cmd)
{
@@ -1572,6 +1631,7 @@ static const struct snd_pcm_ops snd_usb_playback_ops = {
.trigger = snd_usb_substream_playback_trigger,
.sync_stop = snd_usb_pcm_sync_stop,
.pointer = snd_usb_pcm_pointer,
+ .ack = snd_usb_pcm_playback_ack,
};
static const struct snd_pcm_ops snd_usb_capture_ops = {