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Diffstat (limited to 'sound/usb/pcm.c')
-rw-r--r--sound/usb/pcm.c102
1 files changed, 81 insertions, 21 deletions
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 = {
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-24 08:45:47 +0300