linux/sound/usb/endpoint.h
Takashi Iwai 813a17cab9 ALSA: usb-audio: Avoid killing in-flight URBs during draining
While draining a stream, ALSA PCM core stops the stream by issuing
snd_pcm_stop() after all data has been sent out.  And, at PCM trigger
stop, currently USB-audio driver kills the in-flight URBs explicitly,
then at sync-stop ops, sync with the finish of all remaining URBs.
This might result in a drop of the drained samples as most of
USB-audio devices / hosts allow relatively long in-flight samples (as
a sort of FIFO).

For avoiding the trimming, this patch changes the stream-stop behavior
during PCM draining state.  Under that condition, the pending URBs
won't be killed.  The leftover in-flight URBs are caught by the
sync-stop operation that shall be performed after the trigger-stop
operation.

Link: https://lore.kernel.org/r/20210929080844.11583-10-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2021-09-30 13:55:26 +02:00

56 lines
2.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __USBAUDIO_ENDPOINT_H
#define __USBAUDIO_ENDPOINT_H
#define SND_USB_ENDPOINT_TYPE_DATA 0
#define SND_USB_ENDPOINT_TYPE_SYNC 1
struct snd_usb_endpoint *snd_usb_get_endpoint(struct snd_usb_audio *chip,
int ep_num);
int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type);
struct snd_usb_endpoint *
snd_usb_endpoint_open(struct snd_usb_audio *chip,
const struct audioformat *fp,
const struct snd_pcm_hw_params *params,
bool is_sync_ep);
void snd_usb_endpoint_close(struct snd_usb_audio *chip,
struct snd_usb_endpoint *ep);
int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
struct snd_usb_endpoint *ep);
int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock);
bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
struct snd_usb_endpoint *ep,
const struct audioformat *fp,
const struct snd_pcm_hw_params *params);
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,
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);
int snd_usb_endpoint_start(struct snd_usb_endpoint *ep);
void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending);
void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep);
void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep);
int snd_usb_endpoint_activate(struct snd_usb_endpoint *ep);
void snd_usb_endpoint_release(struct snd_usb_endpoint *ep);
void snd_usb_endpoint_free_all(struct snd_usb_audio *chip);
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 */