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LookingGlass/client/src/usb_audio.c
Geoffrey McRae 173316a5a9 [client] audio: handle USB transport backpressure
2026-08-12 14:36:50 +10:00

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/**
* Looking Glass
* Copyright © 2017-2026 The Looking Glass Authors
* https://looking-glass.io
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "usb_audio.h"
#include "common/debug.h"
#include "common/event.h"
#include "common/ringbuffer.h"
#include "common/time.h"
#include <usbredirparser.h>
#include <inttypes.h>
#include <limits.h>
#include <stdbool.h>
#include <stdatomic.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
enum
{
USB_AUDIO_VENDOR_ID = 0x043e,
USB_AUDIO_PRODUCT_ID = 0x0001,
USB_AUDIO_DEVICE_VERSION = 0x010d,
USB_AUDIO_CONFIGURATION = 1,
USB_AUDIO_PLAYBACK_CONTROL_IFACE = 0,
USB_AUDIO_PLAYBACK_IFACE = 1,
USB_AUDIO_RECORD_CONTROL_IFACE = 2,
USB_AUDIO_RECORD_IFACE = 3,
USB_AUDIO_PLAYBACK_CLOCK_ID = 1,
USB_AUDIO_RECORD_CLOCK_ID = 1,
USB_AUDIO_PLAYBACK_DATA_ENDPOINT = 0x01,
USB_AUDIO_FEEDBACK_ENDPOINT = 0x81,
USB_AUDIO_RECORD_DATA_ENDPOINT = 0x82,
USB_AUDIO_PLAYBACK_DATA_EP_INDEX = 1,
USB_AUDIO_FEEDBACK_EP_INDEX = 17,
USB_AUDIO_RECORD_DATA_EP_INDEX = 18,
USB_AUDIO_PLAYBACK_DATA_INTERVAL = 1,
USB_AUDIO_FEEDBACK_INTERVAL = 8,
USB_AUDIO_RECORD_DATA_INTERVAL = 4,
USB_AUDIO_FEEDBACK_BINTERVAL = 4,
USB_AUDIO_RECORD_DATA_BINTERVAL = 3,
USB_AUDIO_FEEDBACK_SIZE = 4,
USB_AUDIO_FEEDBACK_MAX_QUEUE = 512,
USB_AUDIO_SAMPLE_SIZE = 3,
USB_AUDIO_MAX_SAMPLE_RATE = 192000,
USB_AUDIO_PLAYBACK_MAX_CHANNELS = 8,
USB_AUDIO_PLAYBACK_HS_PACKET_FRAMES = 25,
USB_AUDIO_PLAYBACK_BATCH_PACKETS = USB_AUDIO_FEEDBACK_INTERVAL,
USB_AUDIO_PLAYBACK_BATCH_FRAMES =
USB_AUDIO_PLAYBACK_HS_PACKET_FRAMES * USB_AUDIO_PLAYBACK_BATCH_PACKETS,
USB_AUDIO_PLAYBACK_BATCH_SIZE =
USB_AUDIO_PLAYBACK_BATCH_FRAMES *
USB_AUDIO_PLAYBACK_MAX_CHANNELS * USB_AUDIO_SAMPLE_SIZE,
USB_AUDIO_FS_PACKET_FRAMES = 97,
USB_AUDIO_RECORD_PACKET_FRAMES = 97,
USB_AUDIO_RECORD_PACKETS_PER_SECOND = 2000,
USB_AUDIO_RECORD_PACKET_INTERVAL_NS = 500000,
USB_AUDIO_FEEDBACK_PERIOD_NS = 1000000,
USB_AUDIO_RECORD_RATE_SCALE = 65536,
USB_AUDIO_RECORD_RATE_SETTLE_NS = 2000000000,
USB_AUDIO_RECORD_RATE_GAP_NS = 100000000,
USB_AUDIO_RECORD_RATE_DENOMINATOR =
USB_AUDIO_RECORD_PACKETS_PER_SECOND * USB_AUDIO_RECORD_RATE_SCALE,
USB_AUDIO_RECORD_MAX_BATCH = 128,
USB_AUDIO_RECORD_MAX_SAFETY_PACKETS =
USB_AUDIO_RECORD_PACKETS_PER_SECOND / 10,
/* Hold the complete QEMU ISO-IN safety window in addition to the normal
* 20 ms queue target at the maximum supported sample rate. */
USB_AUDIO_RECORD_QUEUE_FRAMES =
USB_AUDIO_RECORD_MAX_SAFETY_PACKETS *
USB_AUDIO_RECORD_PACKET_FRAMES +
USB_AUDIO_MAX_SAMPLE_RATE / 50,
USB_AUDIO_RECORD_FRAME_SIZE =
2 * USB_AUDIO_SAMPLE_SIZE,
USB_AUDIO_RECORD_PACKET_SIZE =
USB_AUDIO_RECORD_PACKET_FRAMES * USB_AUDIO_RECORD_FRAME_SIZE,
USB_AUDIO_CONFIGURATION_DESC_SIZE = 9,
USB_AUDIO_FUNCTION_CONTROL_SIZE = 63,
USB_AUDIO_PLAYBACK_STREAM_DESC_SIZE = 53,
USB_AUDIO_RECORD_STREAM_DESC_SIZE = 46,
};
#define USB_AUDIO_RECORD_DEBUG_INTERVAL_NS UINT64_C(5000000000)
#define USB_AUDIO_PLAYBACK_DEBUG_INTERVAL_NS UINT64_C(5000000000)
enum
{
USB_AUDIO_LAYOUT_STEREO = 0x00000003,
USB_AUDIO_LAYOUT_QUAD = 0x00000033,
USB_AUDIO_LAYOUT_5POINT1 = 0x0000003f,
USB_AUDIO_LAYOUT_7POINT1 = 0x0000063f,
};
#define USB_AUDIO_LAYOUTS(X) \
X(1, 8, USB_AUDIO_LAYOUT_7POINT1) \
X(2, 6, USB_AUDIO_LAYOUT_5POINT1) \
X(3, 4, USB_AUDIO_LAYOUT_QUAD ) \
X(4, 2, USB_AUDIO_LAYOUT_STEREO )
#define USB_AUDIO_COUNT_LAYOUT(alt, channels, mask) + 1
enum
{
USB_AUDIO_LAYOUT_COUNT =
0 USB_AUDIO_LAYOUTS(USB_AUDIO_COUNT_LAYOUT),
USB_AUDIO_RECORD_FUNCTION_OFFSET =
USB_AUDIO_CONFIGURATION_DESC_SIZE +
USB_AUDIO_FUNCTION_CONTROL_SIZE + 9 +
USB_AUDIO_LAYOUT_COUNT * USB_AUDIO_PLAYBACK_STREAM_DESC_SIZE,
USB_AUDIO_CONFIGURATION_SIZE =
USB_AUDIO_RECORD_FUNCTION_OFFSET +
USB_AUDIO_FUNCTION_CONTROL_SIZE +
9 + USB_AUDIO_RECORD_STREAM_DESC_SIZE,
USB_AUDIO_OTHER_SPEED_SIZE =
USB_AUDIO_CONFIGURATION_DESC_SIZE +
USB_AUDIO_FUNCTION_CONTROL_SIZE +
9 + USB_AUDIO_PLAYBACK_STREAM_DESC_SIZE +
USB_AUDIO_FUNCTION_CONTROL_SIZE +
9 + USB_AUDIO_RECORD_STREAM_DESC_SIZE,
};
#undef USB_AUDIO_COUNT_LAYOUT
#define USB_AUDIO_PACKET_SIZE(frames, channels) \
((frames) * (channels) * USB_AUDIO_SAMPLE_SIZE)
typedef struct USBAudioLayout
{
uint32_t channelMask;
uint8_t channelCount;
}
USBAudioLayout;
#define USB_AUDIO_LAYOUT_ENTRY(alt, channels, mask) \
[alt - 1] = { .channelMask = mask, .channelCount = channels },
static const USBAudioLayout l_channelLayouts[] =
{
USB_AUDIO_LAYOUTS(USB_AUDIO_LAYOUT_ENTRY)
};
#undef USB_AUDIO_LAYOUT_ENTRY
enum
{
USB_REQUEST_GET_STATUS = 0x00,
USB_REQUEST_GET_DESCRIPTOR = 0x06,
USB_REQUEST_CUR = 0x01,
USB_REQUEST_RANGE = 0x02,
};
enum
{
USB_REQUEST_TYPE_IN_STANDARD_DEVICE = 0x80,
USB_REQUEST_TYPE_IN_STANDARD_INTERFACE = 0x81,
USB_REQUEST_TYPE_IN_STANDARD_ENDPOINT = 0x82,
USB_REQUEST_TYPE_OUT_CLASS_INTERFACE = 0x21,
USB_REQUEST_TYPE_IN_CLASS_INTERFACE = 0xa1,
};
enum
{
USB_DESCRIPTOR_DEVICE = 0x01,
USB_DESCRIPTOR_CONFIGURATION = 0x02,
USB_DESCRIPTOR_STRING = 0x03,
USB_DESCRIPTOR_DEVICE_QUALIFIER = 0x06,
USB_DESCRIPTOR_OTHER_SPEED = 0x07,
};
enum
{
USB_AUDIO_CONTROL_FREQUENCY = 0x01,
USB_AUDIO_CONTROL_VALIDITY = 0x02,
};
static const uint8_t l_deviceDescriptor[] =
{
0x12, 0x01, 0x00, 0x02, 0xef, 0x02, 0x01, 0x40,
0x3e, 0x04, 0x01, 0x00,
USB_AUDIO_DEVICE_VERSION & 0xff,
USB_AUDIO_DEVICE_VERSION >> 8 & 0xff,
0x01, 0x02,
0x03, 0x01,
};
#define USB_AUDIO_PLAYBACK_STREAM_DESCRIPTOR(alt, channels, mask, \
packetFrames, feedbackSize, feedbackInterval) \
0x09, 0x04, USB_AUDIO_PLAYBACK_IFACE, alt, \
0x02, 0x01, 0x02, 0x20, 0x00, \
0x10, 0x24, 0x01, 0x02, 0x00, 0x01, 0x01, 0x00, 0x00, 0x00, \
channels, \
(mask) & 0xff, \
(mask) >> 8 & 0xff, \
(mask) >> 16 & 0xff, \
(mask) >> 24 & 0xff, \
0x00, \
0x06, 0x24, 0x02, 0x01, 0x03, 0x18, \
0x07, 0x05, USB_AUDIO_PLAYBACK_DATA_ENDPOINT, 0x05, \
USB_AUDIO_PACKET_SIZE(packetFrames, channels) & 0xff, \
USB_AUDIO_PACKET_SIZE(packetFrames, channels) >> 8 & 0xff, \
USB_AUDIO_PLAYBACK_DATA_INTERVAL, \
0x08, 0x25, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, \
0x07, 0x05, USB_AUDIO_FEEDBACK_ENDPOINT, 0x11, \
feedbackSize, 0x00, feedbackInterval,
#define USB_AUDIO_PLAYBACK_HS_STREAM_DESCRIPTOR(alt, channels, mask) \
USB_AUDIO_PLAYBACK_STREAM_DESCRIPTOR( \
alt, channels, mask, USB_AUDIO_PLAYBACK_HS_PACKET_FRAMES, \
USB_AUDIO_FEEDBACK_SIZE, USB_AUDIO_FEEDBACK_BINTERVAL)
#define USB_AUDIO_RECORD_STREAM_DESCRIPTOR(packetFrames, interval) \
0x09, 0x04, USB_AUDIO_RECORD_IFACE, 0x01, \
0x01, 0x01, 0x02, 0x20, 0x00, \
0x10, 0x24, 0x01, 0x03, 0x00, 0x01, 0x01, 0x00, 0x00, 0x00, \
0x02, 0x03, 0x00, 0x00, 0x00, 0x00, \
0x06, 0x24, 0x02, 0x01, 0x03, 0x18, \
0x07, 0x05, USB_AUDIO_RECORD_DATA_ENDPOINT, 0x05, \
USB_AUDIO_PACKET_SIZE(packetFrames, 2) & 0xff, \
USB_AUDIO_PACKET_SIZE(packetFrames, 2) >> 8 & 0xff, \
interval, \
0x08, 0x25, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
static const uint8_t l_configurationDescriptor[] =
{
/* Configuration */
0x09, 0x02,
USB_AUDIO_CONFIGURATION_SIZE & 0xff,
USB_AUDIO_CONFIGURATION_SIZE >> 8 & 0xff,
0x04, 0x01, 0x00, 0x80, 0x32,
/* Playback audio function */
0x08, 0x0b, USB_AUDIO_PLAYBACK_CONTROL_IFACE, 0x02,
0x01, 0x00, 0x20, 0x02,
0x09, 0x04, USB_AUDIO_PLAYBACK_CONTROL_IFACE, 0x00,
0x00, 0x01, 0x01, 0x20, 0x00,
0x09, 0x24, 0x01, 0x00, 0x02, 0x02, 0x2e, 0x00, 0x00,
0x08, 0x24, 0x0a, USB_AUDIO_PLAYBACK_CLOCK_ID,
0x03, 0x07, 0x00, 0x00,
0x11, 0x24, 0x02, 0x02, 0x01, 0x01, 0x00, 0x01, 0x08,
0x3f, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x0c, 0x24, 0x03, 0x03, 0x01, 0x03, 0x00, 0x02, 0x01,
0x00, 0x00, 0x00,
/* Playback interface, idle alternate setting */
0x09, 0x04, USB_AUDIO_PLAYBACK_IFACE, 0x00,
0x00, 0x01, 0x02, 0x20, 0x00,
/* Publish the maximum topology first for the Windows endpoint model. */
USB_AUDIO_LAYOUTS(USB_AUDIO_PLAYBACK_HS_STREAM_DESCRIPTOR)
/* Recording audio function */
0x08, 0x0b, USB_AUDIO_RECORD_CONTROL_IFACE, 0x02,
0x01, 0x00, 0x20, 0x04,
0x09, 0x04, USB_AUDIO_RECORD_CONTROL_IFACE, 0x00,
0x00, 0x01, 0x01, 0x20, 0x00,
0x09, 0x24, 0x01, 0x00, 0x02, 0x03, 0x2e, 0x00, 0x00,
0x08, 0x24, 0x0a, USB_AUDIO_RECORD_CLOCK_ID,
0x03, 0x07, 0x00, 0x00,
0x11, 0x24, 0x02, 0x02, 0x01, 0x02, 0x00, 0x01, 0x02,
0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04,
0x0c, 0x24, 0x03, 0x03, 0x01, 0x01, 0x00, 0x02, 0x01,
0x00, 0x00, 0x00,
/* Recording interface, idle alternate setting */
0x09, 0x04, USB_AUDIO_RECORD_IFACE, 0x00,
0x00, 0x01, 0x02, 0x20, 0x00,
USB_AUDIO_RECORD_STREAM_DESCRIPTOR(
USB_AUDIO_RECORD_PACKET_FRAMES,
USB_AUDIO_RECORD_DATA_BINTERVAL)
};
#undef USB_AUDIO_PLAYBACK_HS_STREAM_DESCRIPTOR
#undef USB_AUDIO_LAYOUTS
static const uint8_t l_fullSpeedPlaybackDescriptor[] =
{
0x09, 0x04, USB_AUDIO_PLAYBACK_IFACE, 0x00,
0x00, 0x01, 0x02, 0x20, 0x00,
USB_AUDIO_PLAYBACK_STREAM_DESCRIPTOR(1, 2, USB_AUDIO_LAYOUT_STEREO,
USB_AUDIO_FS_PACKET_FRAMES, 3, 1)
};
static const uint8_t l_fullSpeedRecordDescriptor[] =
{
0x09, 0x04, USB_AUDIO_RECORD_IFACE, 0x00,
0x00, 0x01, 0x02, 0x20, 0x00,
USB_AUDIO_RECORD_STREAM_DESCRIPTOR(
USB_AUDIO_FS_PACKET_FRAMES, 1)
};
#undef USB_AUDIO_RECORD_STREAM_DESCRIPTOR
#undef USB_AUDIO_PLAYBACK_STREAM_DESCRIPTOR
#undef USB_AUDIO_PACKET_SIZE
static const uint8_t l_deviceQualifierDescriptor[] =
{
0x0a, 0x06, 0x00, 0x02, 0xef, 0x02, 0x01, 0x40, 0x01, 0x00,
};
static const uint32_t l_sampleRates[] =
{
44100,
48000,
88200,
96000,
176400,
USB_AUDIO_MAX_SAMPLE_RATE,
};
static const uint8_t l_clockValid[] = { 0x01 };
static const uint8_t l_zeroStatus[] = { 0x00, 0x00 };
_Static_assert(sizeof(l_deviceDescriptor) == 18,
"invalid USB device descriptor size");
_Static_assert(sizeof(l_channelLayouts) / sizeof(*l_channelLayouts) ==
USB_AUDIO_LAYOUT_COUNT, "invalid USB audio layout count");
_Static_assert(sizeof(l_configurationDescriptor) ==
USB_AUDIO_CONFIGURATION_SIZE,
"invalid USB configuration descriptor size");
_Static_assert(sizeof(l_fullSpeedPlaybackDescriptor) ==
9 + USB_AUDIO_PLAYBACK_STREAM_DESC_SIZE,
"invalid full-speed playback descriptor size");
_Static_assert(sizeof(l_fullSpeedRecordDescriptor) ==
9 + USB_AUDIO_RECORD_STREAM_DESC_SIZE,
"invalid full-speed recording descriptor size");
_Static_assert(sizeof(l_deviceQualifierDescriptor) == 10,
"invalid USB device qualifier descriptor size");
_Static_assert(USB_AUDIO_OTHER_SPEED_SIZE <=
sizeof(l_configurationDescriptor), "invalid other-speed descriptor size");
_Static_assert(USB_AUDIO_FS_PACKET_FRAMES * 2 * USB_AUDIO_SAMPLE_SIZE <=
1023, "full-speed stream packet is too large");
_Static_assert(USB_AUDIO_RECORD_PACKET_SIZE <= 1024,
"high-speed recording packet is too large");
typedef enum
{
RECORD_RATE_NONE,
RECORD_RATE_ARRIVAL,
RECORD_RATE_SOURCE
}
RecordRateMode;
struct LG_USBAudio
{
const LG_USBAudioEventOps * events;
void * eventOpaque;
struct usbredirparser * parser;
bool debug;
uint8_t configuration;
uint8_t playbackAlt;
uint8_t recordAlt;
uint32_t playbackSampleRate;
atomic_uint recordSampleRate;
bool playbackStreaming;
uint8_t playbackBatchPackets;
uint8_t playbackBatchFrameSize;
uint16_t playbackBatchFrames;
uint32_t playbackPacketPhase;
bool playbackErrorWarned;
uint64_t playbackConcealedPackets;
uint64_t playbackInvalidPackets;
uint64_t playbackNextDebugTime;
atomic_bool feedbackStreaming;
uint64_t feedbackPacketId;
uint64_t feedbackNextPacketTime;
uint32_t feedbackQueueTarget;
atomic_uint feedbackValue;
bool outputBackpressured;
atomic_bool recordStreaming;
atomic_bool recordAccepting;
atomic_bool recordOverflowPending;
atomic_uint recordGeneration;
atomic_uint recordInFlight;
LGEvent * recordIdle;
uint64_t recordPacketId;
uint64_t recordPacketPhase;
uint64_t recordNextPacketTime;
uint32_t recordBatchPackets;
uint32_t recordSafetyPackets;
uint32_t recordRefillPackets;
RingBuffer recordBuffer;
atomic_uint_fast64_t recordRateQ16;
RecordRateMode recordRateMode;
uint64_t recordArrivalStartTime;
uint64_t recordArrivalLastTime;
uint64_t recordArrivalFrames;
uint64_t recordSourceStartPosition;
uint64_t recordSourceLastPosition;
int64_t recordSourceStartTime;
int64_t recordSourceLastTime;
atomic_uint_fast64_t recordOverflowFrames;
atomic_uint_fast64_t recordUnderflowFrames;
atomic_uint_fast64_t recordTrimmedFrames;
atomic_uint_fast64_t recordLatePackets;
atomic_uint_fast64_t recordMaxLateness;
atomic_uint_fast64_t recordDiscontinuities;
uint64_t recordNextDebugTime;
uint8_t playbackBatch[USB_AUDIO_PLAYBACK_BATCH_SIZE];
};
static LG_USBAudio * getAudio(void * opaque)
{
return lgUsbRedir_device(opaque);
}
static uint64_t streamTime(void)
{
/* PipeWire timestamps use CLOCK_MONOTONIC. Keep USB stream scheduling in
* that domain instead of introducing MONOTONIC_RAW clock drift. */
return microtime() * UINT64_C(1000);
}
static void recordCounterMax(
atomic_uint_fast64_t * counter, uint64_t value)
{
uint_fast64_t current = atomic_load_explicit(
counter, memory_order_relaxed);
while (current < value && !atomic_compare_exchange_weak_explicit(
counter, &current, value,
memory_order_relaxed, memory_order_relaxed))
;
}
static void recordDisableInput(LG_USBAudio * audio)
{
/* A producer takes the generation before entering recordInFlight. Changing
* both values prevents a callback which raced the gate from entering after
* the consumer has reset the SPSC queue. */
atomic_store_explicit(
&audio->recordAccepting, false, memory_order_seq_cst);
atomic_fetch_add_explicit(
&audio->recordGeneration, 1, memory_order_seq_cst);
}
static void recordWaitForInput(LG_USBAudio * audio)
{
while (atomic_load_explicit(
&audio->recordInFlight, memory_order_seq_cst))
if (!lgWaitEvent(audio->recordIdle, TIMEOUT_INFINITE))
DEBUG_FATAL("Failed to wait for USB capture callbacks");
}
static int recordDiscardQueued(LG_USBAudio * audio)
{
const int queued = ringbuffer_getCount(audio->recordBuffer);
return queued > 0 ?
ringbuffer_consume(audio->recordBuffer, NULL, queued) : 0;
}
static uint32_t readLE32(const uint8_t * data)
{
return
(uint32_t)data[0] |
(uint32_t)data[1] << 8 |
(uint32_t)data[2] << 16 |
(uint32_t)data[3] << 24;
}
static void writeLE16(uint8_t * data, uint16_t value)
{
data[0] = value;
data[1] = value >> 8;
}
static void writeLE32(uint8_t * data, uint32_t value)
{
data[0] = value;
data[1] = value >> 8;
data[2] = value >> 16;
data[3] = value >> 24;
}
static uint32_t encodeFeedbackRate(double sampleRate)
{
return (uint32_t)(sampleRate * UINT32_C(65536) / 8000.0 + 0.5);
}
static void resetFeedbackRate(LG_USBAudio * audio)
{
atomic_store_explicit(&audio->feedbackValue,
encodeFeedbackRate(audio->playbackSampleRate), memory_order_release);
}
static uint32_t nextPlaybackPacketFrames(LG_USBAudio * audio)
{
const uint64_t phase = audio->playbackPacketPhase +
atomic_load_explicit(&audio->feedbackValue, memory_order_acquire);
audio->playbackPacketPhase = phase & UINT32_C(0xffff);
return (uint32_t)(phase >> 16);
}
static uint32_t nearestSampleRate(uint32_t sampleRate)
{
uint32_t selected = l_sampleRates[0];
uint64_t bestDelta = sampleRate > selected ?
(uint64_t)sampleRate - selected : (uint64_t)selected - sampleRate;
for (size_t i = 1;
i < sizeof(l_sampleRates) / sizeof(*l_sampleRates); ++i)
{
const uint32_t candidate = l_sampleRates[i];
const uint64_t delta = sampleRate > candidate ?
(uint64_t)sampleRate - candidate : (uint64_t)candidate - sampleRate;
if (delta < bestDelta)
{
selected = candidate;
bestDelta = delta;
}
}
return selected;
}
static const USBAudioLayout * getLayout(uint8_t alt)
{
if (alt == 0 || alt > USB_AUDIO_LAYOUT_COUNT)
return NULL;
return &l_channelLayouts[alt - 1];
}
static uint16_t layoutPacketSize(const USBAudioLayout * layout)
{
return USB_AUDIO_PLAYBACK_HS_PACKET_FRAMES * layout->channelCount *
USB_AUDIO_SAMPLE_SIZE;
}
static size_t writeSampleRateRange(uint8_t * buffer)
{
const size_t count = sizeof(l_sampleRates) / sizeof(*l_sampleRates);
writeLE16(buffer, (uint16_t)count);
uint8_t * range = buffer + 2;
for (size_t i = 0; i < count; ++i, range += 12)
{
writeLE32(range , l_sampleRates[i]);
writeLE32(range + 4, l_sampleRates[i]);
writeLE32(range + 8, 0);
}
return 2 + count * 12;
}
static void flushPlayback(LG_USBAudio * audio)
{
const size_t frames = audio->playbackBatchFrames;
audio->playbackBatchPackets = 0;
audio->playbackBatchFrameSize = 0;
audio->playbackBatchFrames = 0;
if (frames && audio->playbackStreaming && audio->events &&
audio->events->playbackData)
audio->events->playbackData(
audio->eventOpaque, audio->playbackBatch, frames);
}
static void queuePlaybackPacket(LG_USBAudio * audio,
const uint8_t * data, size_t frames, uint8_t frameSize)
{
if (audio->playbackBatchPackets == USB_AUDIO_PLAYBACK_BATCH_PACKETS ||
audio->playbackBatchFrames + frames >
USB_AUDIO_PLAYBACK_BATCH_FRAMES ||
(audio->playbackBatchFrames &&
audio->playbackBatchFrameSize != frameSize))
flushPlayback(audio);
if (frames)
{
uint8_t * destination = audio->playbackBatch +
(size_t)audio->playbackBatchFrames * frameSize;
if (data)
memcpy(destination, data, frames * frameSize);
else
memset(destination, 0, frames * frameSize);
audio->playbackBatchFrameSize = frameSize;
audio->playbackBatchFrames += (uint16_t)frames;
}
++audio->playbackBatchPackets;
}
static void stopPlayback(LG_USBAudio * audio)
{
flushPlayback(audio);
audio->playbackPacketPhase = 0;
if (!audio->playbackStreaming)
return;
audio->playbackStreaming = false;
resetFeedbackRate(audio);
if (audio->events && audio->events->playbackStop)
audio->events->playbackStop(audio->eventOpaque);
}
static void stopFeedback(LG_USBAudio * audio)
{
atomic_store_explicit(
&audio->feedbackStreaming, false, memory_order_release);
audio->feedbackPacketId = 0;
audio->feedbackNextPacketTime = 0;
audio->feedbackQueueTarget = 0;
}
static void stopPlaybackStreams(LG_USBAudio * audio)
{
stopPlayback(audio);
stopFeedback(audio);
}
static void startPlayback(LG_USBAudio * audio)
{
const USBAudioLayout * layout = getLayout(audio->playbackAlt);
if (audio->playbackStreaming || !layout)
return;
resetFeedbackRate(audio);
audio->playbackPacketPhase = 0;
audio->playbackErrorWarned = false;
audio->playbackConcealedPackets = 0;
audio->playbackInvalidPackets = 0;
audio->playbackNextDebugTime = 0;
audio->playbackStreaming = true;
if (audio->events && audio->events->playbackStart)
audio->events->playbackStart(
audio->eventOpaque, audio->playbackSampleRate,
layout->channelMask);
}
static void stopRecord(LG_USBAudio * audio)
{
if (!atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
return;
recordDisableInput(audio);
atomic_store_explicit(
&audio->recordStreaming, false, memory_order_release);
if (audio->events && audio->events->recordStop)
audio->events->recordStop(audio->eventOpaque);
recordWaitForInput(audio);
ringbuffer_reset(audio->recordBuffer);
atomic_store_explicit(
&audio->recordOverflowPending, false, memory_order_relaxed);
audio->recordRefillPackets = 0;
}
static void clearRecordRateWindows(LG_USBAudio * audio)
{
audio->recordRateMode = RECORD_RATE_NONE;
audio->recordArrivalStartTime = 0;
audio->recordArrivalLastTime = 0;
audio->recordArrivalFrames = 0;
audio->recordSourceStartPosition = 0;
audio->recordSourceLastPosition = 0;
audio->recordSourceStartTime = 0;
audio->recordSourceLastTime = 0;
}
static void resetRecordRate(
LG_USBAudio * audio, uint32_t sampleRate)
{
atomic_store_explicit(&audio->recordRateQ16,
(uint64_t)sampleRate * USB_AUDIO_RECORD_RATE_SCALE,
memory_order_release);
clearRecordRateWindows(audio);
}
static bool recordRateInRange(
uint32_t sampleRate, double measured)
{
return measured >= sampleRate * 0.995 &&
measured <= sampleRate * 1.005;
}
static void updateMeasuredRecordRate(
LG_USBAudio * audio, double measured)
{
const uint64_t measuredQ16 = (uint64_t)(
measured * USB_AUDIO_RECORD_RATE_SCALE + 0.5);
const uint64_t currentQ16 = atomic_load_explicit(
&audio->recordRateQ16, memory_order_relaxed);
atomic_store_explicit(&audio->recordRateQ16,
(currentQ16 * 3 + measuredQ16) / 4,
memory_order_release);
}
static void startRecordArrivalWindow(
LG_USBAudio * audio, uint64_t now)
{
clearRecordRateWindows(audio);
audio->recordRateMode = RECORD_RATE_ARRIVAL;
audio->recordArrivalStartTime = now;
audio->recordArrivalLastTime = now;
}
static void updateRecordArrivalRate(
LG_USBAudio * audio, uint32_t sampleRate, size_t frames)
{
const uint64_t now = streamTime();
if (audio->recordRateMode != RECORD_RATE_ARRIVAL)
{
/* Preserve the current rate while a temporarily absent source clock
* starts a fresh fallback window. */
startRecordArrivalWindow(audio, now);
return;
}
if (now < audio->recordArrivalLastTime ||
now - audio->recordArrivalLastTime > USB_AUDIO_RECORD_RATE_GAP_NS)
{
atomic_store_explicit(&audio->recordRateQ16,
(uint64_t)sampleRate * USB_AUDIO_RECORD_RATE_SCALE,
memory_order_release);
startRecordArrivalWindow(audio, now);
return;
}
audio->recordArrivalFrames += frames;
audio->recordArrivalLastTime = now;
const uint64_t elapsed = now - audio->recordArrivalStartTime;
if (elapsed < USB_AUDIO_RECORD_RATE_SETTLE_NS)
return;
const double measured =
(double)audio->recordArrivalFrames * 1000000000.0 / elapsed;
if (recordRateInRange(sampleRate, measured))
updateMeasuredRecordRate(audio, measured);
audio->recordArrivalStartTime = now;
audio->recordArrivalFrames = 0;
}
static void startRecordSourceWindow(
LG_USBAudio * audio, const LG_AudioClock * sourceClock)
{
clearRecordRateWindows(audio);
audio->recordRateMode = RECORD_RATE_SOURCE;
audio->recordSourceStartPosition = sourceClock->position;
audio->recordSourceLastPosition = sourceClock->position;
audio->recordSourceStartTime = sourceClock->time;
audio->recordSourceLastTime = sourceClock->time;
}
static bool updateRecordSourceRate(LG_USBAudio * audio,
uint32_t sampleRate, const LG_AudioClock * sourceClock)
{
if (sourceClock->discontinuity)
{
resetRecordRate(audio, sampleRate);
return false;
}
if (audio->recordRateMode != RECORD_RATE_SOURCE)
{
/* Clock stability is not needed to establish the first position/time
* baseline. */
startRecordSourceWindow(audio, sourceClock);
return true;
}
if (sourceClock->position <= audio->recordSourceLastPosition ||
sourceClock->time <= audio->recordSourceLastTime)
{
resetRecordRate(audio, sampleRate);
return false;
}
if (!sourceClock->stable)
{
/* Keep an unstable clock as the next baseline, but do not let it
* contribute to the measured device rate. */
startRecordSourceWindow(audio, sourceClock);
return true;
}
audio->recordSourceLastPosition = sourceClock->position;
audio->recordSourceLastTime = sourceClock->time;
const int64_t elapsed =
sourceClock->time - audio->recordSourceStartTime;
if (elapsed < USB_AUDIO_RECORD_RATE_SETTLE_NS)
return true;
const double measured =
(double)(sourceClock->position -
audio->recordSourceStartPosition) * 1000000000.0 / elapsed;
if (!recordRateInRange(sampleRate, measured))
{
resetRecordRate(audio, sampleRate);
return false;
}
updateMeasuredRecordRate(audio, measured);
audio->recordSourceStartPosition = sourceClock->position;
audio->recordSourceStartTime = sourceClock->time;
return true;
}
static void resetRecordData(LG_USBAudio * audio)
{
ringbuffer_reset(audio->recordBuffer);
resetRecordRate(audio, atomic_load_explicit(
&audio->recordSampleRate, memory_order_relaxed));
audio->recordPacketPhase = 0;
audio->recordRefillPackets = 0;
atomic_store_explicit(
&audio->recordOverflowPending, false, memory_order_relaxed);
}
static void startRecord(LG_USBAudio * audio)
{
if (audio->recordAlt != 1 || atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
return;
recordDisableInput(audio);
recordWaitForInput(audio);
resetRecordData(audio);
audio->recordPacketId = 0;
atomic_store_explicit(
&audio->recordStreaming, true, memory_order_release);
if (audio->events && audio->events->recordStart)
audio->events->recordStart(audio->eventOpaque,
atomic_load_explicit(
&audio->recordSampleRate, memory_order_relaxed),
USB_AUDIO_LAYOUT_STEREO);
/* Backend startup may block while the capture graph is configured. Do not
* turn that setup time into a burst of stale USB packets. */
recordWaitForInput(audio);
audio->recordNextPacketTime = streamTime();
atomic_store_explicit(
&audio->recordAccepting, true, memory_order_seq_cst);
}
static void reconfigureRecord(
LG_USBAudio * audio, uint32_t sampleRate)
{
if (!atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
return;
recordDisableInput(audio);
atomic_store_explicit(
&audio->recordSampleRate, sampleRate, memory_order_relaxed);
if (audio->events && audio->events->recordStart)
audio->events->recordStart(audio->eventOpaque,
sampleRate, USB_AUDIO_LAYOUT_STEREO);
/* The provider restart has quiesced the old producer. Drop any frames
* queued around the format transition and restart the USB sample phase. */
recordWaitForInput(audio);
resetRecordData(audio);
audio->recordNextPacketTime = streamTime();
atomic_store_explicit(
&audio->recordAccepting, true, memory_order_seq_cst);
}
static void stopStreams(LG_USBAudio * audio)
{
stopPlaybackStreams(audio);
stopRecord(audio);
}
static void setPlaybackSampleRate(
LG_USBAudio * audio, uint32_t sampleRate)
{
if (audio->playbackSampleRate == sampleRate)
return;
const bool restartPlayback = audio->playbackStreaming;
stopPlayback(audio);
audio->playbackSampleRate = sampleRate;
resetFeedbackRate(audio);
if (restartPlayback)
startPlayback(audio);
}
static void setRecordSampleRate(
LG_USBAudio * audio, uint32_t sampleRate)
{
if (atomic_load_explicit(
&audio->recordSampleRate, memory_order_relaxed) == sampleRate)
return;
if (atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
reconfigureRecord(audio, sampleRate);
else
{
atomic_store_explicit(
&audio->recordSampleRate, sampleRate, memory_order_relaxed);
atomic_store_explicit(&audio->recordRateQ16,
(uint64_t)sampleRate * USB_AUDIO_RECORD_RATE_SCALE,
memory_order_relaxed);
}
}
static void resetDevice(LG_USBAudio * audio)
{
stopStreams(audio);
audio->configuration = 0;
audio->playbackAlt = 0;
audio->recordAlt = 0;
audio->playbackSampleRate = LG_USB_AUDIO_DEFAULT_SAMPLE_RATE;
audio->recordBatchPackets = 1;
audio->recordSafetyPackets = 1;
audio->outputBackpressured = false;
atomic_store_explicit(&audio->recordSampleRate,
LG_USB_AUDIO_DEFAULT_SAMPLE_RATE, memory_order_relaxed);
atomic_store_explicit(&audio->recordRateQ16,
(uint64_t)LG_USB_AUDIO_DEFAULT_SAMPLE_RATE *
USB_AUDIO_RECORD_RATE_SCALE,
memory_order_relaxed);
resetFeedbackRate(audio);
}
static void sendInterfaceInfo(LG_USBAudio * audio)
{
struct usb_redir_interface_info_header info =
{
.interface_count = 4,
.interface =
{
USB_AUDIO_PLAYBACK_CONTROL_IFACE,
USB_AUDIO_PLAYBACK_IFACE,
USB_AUDIO_RECORD_CONTROL_IFACE,
USB_AUDIO_RECORD_IFACE,
},
.interface_class = { 0x01, 0x01, 0x01, 0x01 },
.interface_subclass = { 0x01, 0x02, 0x01, 0x02 },
.interface_protocol = { 0x20, 0x20, 0x20, 0x20 },
};
usbredirparser_send_interface_info(audio->parser, &info);
}
static void sendEndpointInfo(LG_USBAudio * audio)
{
struct usb_redir_ep_info_header info = { 0 };
const USBAudioLayout * layout = getLayout(audio->playbackAlt);
memset(info.type, usb_redir_type_invalid, sizeof(info.type));
info.type[0] = usb_redir_type_control;
info.type[16] = usb_redir_type_control;
info.max_packet_size[0] = 64;
info.max_packet_size[16] = 64;
if (audio->configuration == USB_AUDIO_CONFIGURATION && layout)
{
info.type[USB_AUDIO_PLAYBACK_DATA_EP_INDEX] = usb_redir_type_iso;
info.interval[USB_AUDIO_PLAYBACK_DATA_EP_INDEX] =
USB_AUDIO_PLAYBACK_DATA_INTERVAL;
info.interface[USB_AUDIO_PLAYBACK_DATA_EP_INDEX] =
USB_AUDIO_PLAYBACK_IFACE;
info.max_packet_size[USB_AUDIO_PLAYBACK_DATA_EP_INDEX] =
layoutPacketSize(layout);
info.type[USB_AUDIO_FEEDBACK_EP_INDEX] = usb_redir_type_iso;
info.interval[USB_AUDIO_FEEDBACK_EP_INDEX] =
USB_AUDIO_FEEDBACK_INTERVAL;
info.interface[USB_AUDIO_FEEDBACK_EP_INDEX] =
USB_AUDIO_PLAYBACK_IFACE;
info.max_packet_size[USB_AUDIO_FEEDBACK_EP_INDEX] =
USB_AUDIO_FEEDBACK_SIZE;
}
if (audio->configuration == USB_AUDIO_CONFIGURATION &&
audio->recordAlt == 1)
{
info.type[USB_AUDIO_RECORD_DATA_EP_INDEX] = usb_redir_type_iso;
info.interval[USB_AUDIO_RECORD_DATA_EP_INDEX] =
USB_AUDIO_RECORD_DATA_INTERVAL;
info.interface[USB_AUDIO_RECORD_DATA_EP_INDEX] =
USB_AUDIO_RECORD_IFACE;
info.max_packet_size[USB_AUDIO_RECORD_DATA_EP_INDEX] =
USB_AUDIO_RECORD_PACKET_SIZE;
}
usbredirparser_send_ep_info(audio->parser, &info);
}
static void sendDeviceInfo(LG_USBAudio * audio)
{
sendEndpointInfo(audio);
sendInterfaceInfo(audio);
}
static void resetUSB(void * opaque)
{
LG_USBAudio * audio = getAudio(opaque);
resetDevice(audio);
sendEndpointInfo(audio);
}
static void setConfiguration(void * opaque, uint64_t id,
struct usb_redir_set_configuration_header * request)
{
LG_USBAudio * audio = getAudio(opaque);
struct usb_redir_configuration_status_header status =
{
.status = usb_redir_stall,
.configuration = audio->configuration,
};
if (request->configuration == 0 ||
request->configuration == USB_AUDIO_CONFIGURATION)
{
resetDevice(audio);
audio->configuration = request->configuration;
status.status = usb_redir_success;
status.configuration = audio->configuration;
sendDeviceInfo(audio);
}
usbredirparser_send_configuration_status(audio->parser, id, &status);
}
static void getConfiguration(void * opaque, uint64_t id)
{
LG_USBAudio * audio = getAudio(opaque);
struct usb_redir_configuration_status_header status =
{
.status = usb_redir_success,
.configuration = audio->configuration,
};
usbredirparser_send_configuration_status(audio->parser, id, &status);
}
static void setAltSetting(void * opaque, uint64_t id,
struct usb_redir_set_alt_setting_header * request)
{
LG_USBAudio * audio = getAudio(opaque);
flushPlayback(audio);
struct usb_redir_alt_setting_status_header status =
{
.status = usb_redir_stall,
.interface = request->interface,
.alt = request->alt,
};
if (audio->configuration == USB_AUDIO_CONFIGURATION &&
(request->interface == USB_AUDIO_PLAYBACK_CONTROL_IFACE ||
request->interface == USB_AUDIO_RECORD_CONTROL_IFACE) &&
request->alt == 0)
status.status = usb_redir_success;
else if (audio->configuration == USB_AUDIO_CONFIGURATION &&
request->interface == USB_AUDIO_PLAYBACK_IFACE &&
(request->alt == 0 || getLayout(request->alt)))
{
stopPlaybackStreams(audio);
audio->playbackAlt = request->alt;
status.status = usb_redir_success;
}
else if (audio->configuration == USB_AUDIO_CONFIGURATION &&
request->interface == USB_AUDIO_RECORD_IFACE &&
request->alt <= 1)
{
stopRecord(audio);
audio->recordAlt = request->alt;
status.status = usb_redir_success;
}
if (status.status == usb_redir_success)
sendDeviceInfo(audio);
usbredirparser_send_alt_setting_status(audio->parser, id, &status);
}
static void getAltSetting(void * opaque, uint64_t id,
struct usb_redir_get_alt_setting_header * request)
{
LG_USBAudio * audio = getAudio(opaque);
struct usb_redir_alt_setting_status_header status =
{
.status = usb_redir_stall,
.interface = request->interface,
.alt = 0,
};
if (audio->configuration == USB_AUDIO_CONFIGURATION &&
(request->interface == USB_AUDIO_PLAYBACK_CONTROL_IFACE ||
request->interface == USB_AUDIO_RECORD_CONTROL_IFACE))
status.status = usb_redir_success;
else if (audio->configuration == USB_AUDIO_CONFIGURATION &&
request->interface == USB_AUDIO_PLAYBACK_IFACE)
{
status.status = usb_redir_success;
status.alt = audio->playbackAlt;
}
else if (audio->configuration == USB_AUDIO_CONFIGURATION &&
request->interface == USB_AUDIO_RECORD_IFACE)
{
status.status = usb_redir_success;
status.alt = audio->recordAlt;
}
usbredirparser_send_alt_setting_status(audio->parser, id, &status);
}
static void sendISOStatus(LG_USBAudio * audio, uint64_t id,
uint8_t endpoint, uint8_t result)
{
struct usb_redir_iso_stream_status_header status =
{
.status = result,
.endpoint = endpoint,
};
usbredirparser_send_iso_stream_status(audio->parser, id, &status);
}
static void sendFeedbackPackets(LG_USBAudio * audio, uint32_t count)
{
uint8_t data[USB_AUDIO_FEEDBACK_SIZE];
writeLE32(data, atomic_load_explicit(
&audio->feedbackValue, memory_order_acquire));
struct usb_redir_iso_packet_header packet =
{
.endpoint = USB_AUDIO_FEEDBACK_ENDPOINT,
.status = usb_redir_success,
.length = sizeof(data),
};
for (uint32_t i = 0; i < count; ++i)
usbredirparser_send_iso_packet(audio->parser,
audio->feedbackPacketId++,
&packet, data, USB_AUDIO_FEEDBACK_SIZE);
}
static void sendFeedbackPacketsDue(LG_USBAudio * audio)
{
if (!atomic_load_explicit(
&audio->feedbackStreaming, memory_order_acquire) ||
!audio->feedbackQueueTarget)
return;
const uint64_t now = streamTime();
if (now < audio->feedbackNextPacketTime)
return;
const uint64_t due =
(now - audio->feedbackNextPacketTime) /
USB_AUDIO_FEEDBACK_PERIOD_NS + 1;
sendFeedbackPackets(audio, (uint32_t)min(
due, (uint64_t)audio->feedbackQueueTarget));
if (due > audio->feedbackQueueTarget)
audio->feedbackNextPacketTime =
now + USB_AUDIO_FEEDBACK_PERIOD_NS;
else
audio->feedbackNextPacketTime += due * USB_AUDIO_FEEDBACK_PERIOD_NS;
}
static void sendRecordPacketBatch(LG_USBAudio * audio, uint32_t count,
uint64_t rateQ16, bool forceSilence, uint64_t leadingSilenceFrames,
uint64_t availableFrames)
{
uint8_t data[USB_AUDIO_RECORD_PACKET_SIZE];
uint64_t underflowFrames = 0;
struct usb_redir_iso_packet_header packet =
{
.endpoint = USB_AUDIO_RECORD_DATA_ENDPOINT,
.status = usb_redir_success,
};
for (uint32_t i = 0; i < count; ++i)
{
audio->recordPacketPhase += rateQ16;
const uint32_t frames = (uint32_t)(audio->recordPacketPhase /
USB_AUDIO_RECORD_RATE_DENOMINATOR);
audio->recordPacketPhase %= USB_AUDIO_RECORD_RATE_DENOMINATOR;
DEBUG_ASSERT(frames <= USB_AUDIO_RECORD_PACKET_FRAMES);
const size_t size = frames * USB_AUDIO_RECORD_FRAME_SIZE;
memset(data, 0, size);
if (!forceSilence)
{
const uint32_t leading = (uint32_t)min(
leadingSilenceFrames, (uint64_t)frames);
leadingSilenceFrames -= leading;
underflowFrames += leading;
const uint32_t requested = frames - leading;
const uint32_t available = (uint32_t)min(
availableFrames, (uint64_t)requested);
const int consumed = ringbuffer_consume(audio->recordBuffer,
data + (size_t)leading * USB_AUDIO_RECORD_FRAME_SIZE,
available);
availableFrames -= consumed;
underflowFrames += requested - consumed;
}
packet.length = (uint16_t)size;
usbredirparser_send_iso_packet(audio->parser,
audio->recordPacketId++, &packet, data, (int)size);
}
if (audio->debug && underflowFrames)
atomic_fetch_add_explicit(&audio->recordUnderflowFrames,
underflowFrames, memory_order_relaxed);
}
static void sendRecordRefill(LG_USBAudio * audio, uint64_t rateQ16)
{
const uint32_t count = min(
audio->recordRefillPackets, audio->recordBatchPackets);
sendRecordPacketBatch(audio, count, rateQ16, true, 0, 0);
audio->recordRefillPackets -= count;
if (!audio->recordRefillPackets)
audio->recordNextPacketTime =
streamTime() + USB_AUDIO_RECORD_PACKET_INTERVAL_NS;
}
static void sendRecordPackets(LG_USBAudio * audio)
{
if (!atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
return;
const uint64_t rateQ16 = atomic_load_explicit(
&audio->recordRateQ16, memory_order_acquire);
if (audio->recordRefillPackets)
{
sendRecordRefill(audio, rateQ16);
return;
}
const uint64_t now = streamTime();
if (audio->recordNextPacketTime > now)
return;
const bool overflow = atomic_exchange_explicit(
&audio->recordOverflowPending, false, memory_order_acq_rel);
const uint64_t lateness = now - audio->recordNextPacketTime;
uint64_t count = lateness / USB_AUDIO_RECORD_PACKET_INTERVAL_NS + 1;
if (audio->debug)
{
if (count > 1)
atomic_fetch_add_explicit(&audio->recordLatePackets,
count - 1, memory_order_relaxed);
recordCounterMax(&audio->recordMaxLateness, lateness);
}
if (overflow || count > audio->recordSafetyPackets)
{
const int discarded = recordDiscardQueued(audio);
if (audio->debug)
{
if (discarded)
atomic_fetch_add_explicit(&audio->recordTrimmedFrames,
discarded, memory_order_relaxed);
atomic_fetch_add_explicit(&audio->recordDiscontinuities,
1, memory_order_relaxed);
}
audio->recordPacketPhase = 0;
audio->recordRefillPackets = audio->recordSafetyPackets;
sendRecordRefill(audio, rateQ16);
return;
}
const uint32_t sendCount = (uint32_t)min(
count, (uint64_t)audio->recordBatchPackets);
const uint64_t catchupFrames =
(audio->recordPacketPhase + rateQ16 * count) /
USB_AUDIO_RECORD_RATE_DENOMINATOR;
const uint64_t totalFrames =
(audio->recordPacketPhase + rateQ16 * sendCount) /
USB_AUDIO_RECORD_RATE_DENOMINATOR;
const uint32_t sampleRate = atomic_load_explicit(
&audio->recordSampleRate, memory_order_relaxed);
/* Preserve the samples needed by every overdue packet. Trimming to the
* normal target first would replace valid catch-up audio with silence. */
const int retainFrames = max(
(int)catchupFrames,
max((int)(sampleRate / 50), USB_AUDIO_RECORD_PACKET_FRAMES));
int queued = ringbuffer_getCount(audio->recordBuffer);
if (queued > retainFrames)
{
const int discarded = ringbuffer_consume(
audio->recordBuffer, NULL, queued - retainFrames);
queued -= discarded;
if (audio->debug && discarded)
atomic_fetch_add_explicit(&audio->recordTrimmedFrames,
discarded, memory_order_relaxed);
}
const uint64_t leadingSilenceFrames =
totalFrames > (uint64_t)queued ? totalFrames - queued : 0;
sendRecordPacketBatch(audio, sendCount, rateQ16, false,
leadingSilenceFrames, queued);
audio->recordNextPacketTime +=
(uint64_t)sendCount * USB_AUDIO_RECORD_PACKET_INTERVAL_NS;
}
static void startISOStream(void * opaque, uint64_t id,
struct usb_redir_start_iso_stream_header * request)
{
LG_USBAudio * audio = getAudio(opaque);
flushPlayback(audio);
uint8_t result = usb_redir_stall;
uint32_t feedbackPrefill = 0;
if (audio->configuration == USB_AUDIO_CONFIGURATION)
{
switch (request->endpoint)
{
case USB_AUDIO_PLAYBACK_DATA_ENDPOINT:
if (!getLayout(audio->playbackAlt))
break;
result = usb_redir_success;
startPlayback(audio);
break;
case USB_AUDIO_FEEDBACK_ENDPOINT:
if (!getLayout(audio->playbackAlt))
break;
stopFeedback(audio);
resetFeedbackRate(audio);
feedbackPrefill =
(uint32_t)request->pkts_per_urb * request->no_urbs;
if (!feedbackPrefill)
feedbackPrefill = 1;
else if (feedbackPrefill >
USB_AUDIO_FEEDBACK_MAX_QUEUE)
feedbackPrefill = USB_AUDIO_FEEDBACK_MAX_QUEUE;
audio->feedbackQueueTarget = feedbackPrefill;
result = usb_redir_success;
break;
case USB_AUDIO_RECORD_DATA_ENDPOINT:
if (audio->recordAlt != 1)
break;
audio->recordBatchPackets = max(UINT32_C(1),
min((uint32_t)request->pkts_per_urb,
(uint32_t)USB_AUDIO_RECORD_MAX_BATCH));
audio->recordSafetyPackets = max(UINT32_C(1),
min((uint32_t)request->pkts_per_urb * request->no_urbs,
(uint32_t)USB_AUDIO_RECORD_MAX_SAFETY_PACKETS));
result = usb_redir_success;
startRecord(audio);
break;
}
}
sendISOStatus(audio, id, request->endpoint, result);
if (feedbackPrefill)
{
sendFeedbackPackets(audio, feedbackPrefill);
audio->feedbackNextPacketTime =
streamTime() + USB_AUDIO_FEEDBACK_PERIOD_NS;
atomic_store_explicit(
&audio->feedbackStreaming, true, memory_order_release);
}
}
static void stopISOStream(void * opaque, uint64_t id,
struct usb_redir_stop_iso_stream_header * request)
{
LG_USBAudio * audio = getAudio(opaque);
flushPlayback(audio);
uint8_t result = usb_redir_stall;
switch (request->endpoint)
{
case USB_AUDIO_PLAYBACK_DATA_ENDPOINT:
stopPlayback(audio);
result = usb_redir_success;
break;
case USB_AUDIO_FEEDBACK_ENDPOINT:
stopFeedback(audio);
result = usb_redir_success;
break;
case USB_AUDIO_RECORD_DATA_ENDPOINT:
stopRecord(audio);
result = usb_redir_success;
break;
}
sendISOStatus(audio, id, request->endpoint, result);
}
static void cancelDataPacket(void * opaque, uint64_t id)
{
(void)opaque;
(void)id;
}
static size_t stringDescriptor(uint8_t index, uint8_t * buffer,
size_t bufferSize)
{
if (index == 0)
{
static const uint8_t language[] = { 0x04, 0x03, 0x09, 0x04 };
memcpy(buffer, language, sizeof(language));
return sizeof(language);
}
const char * text;
switch (index)
{
case 1: text = "Looking Glass" ; break;
case 2: text = "Looking Glass USB Audio" ; break;
case 3: text = "LG-UAC2-0006" ; break;
case 4: text = "Looking Glass Microphone" ; break;
default: return 0;
}
const size_t chars = strlen(text);
const size_t size = 2 + chars * 2;
if (size > bufferSize)
return 0;
buffer[0] = (uint8_t)size;
buffer[1] = USB_DESCRIPTOR_STRING;
for (size_t i = 0; i < chars; ++i)
{
buffer[2 + i * 2] = text[i];
buffer[3 + i * 2] = 0;
}
return size;
}
static void sendControlResponse(LG_USBAudio * audio, uint64_t id,
const struct usb_redir_control_packet_header * request, uint8_t status,
const uint8_t * data, size_t size)
{
struct usb_redir_control_packet_header response = *request;
response.status = status;
if (status != usb_redir_success)
{
response.length = 0;
data = NULL;
size = 0;
}
else if (request->requesttype & 0x80)
{
if (size > request->length)
size = request->length;
response.length = (uint16_t)size;
}
else
{
response.length = request->length;
data = NULL;
size = 0;
}
usbredirparser_send_control_packet(audio->parser, id, &response,
(uint8_t *)data, (int)size);
}
static void controlPacket(void * opaque, uint64_t id,
struct usb_redir_control_packet_header * request,
uint8_t * data, int dataLength)
{
LG_USBAudio * audio = getAudio(opaque);
flushPlayback(audio);
uint8_t buffer[sizeof(l_configurationDescriptor)];
const uint8_t * response = NULL;
size_t responseSize = 0;
uint8_t status = usb_redir_stall;
if (request->requesttype == USB_REQUEST_TYPE_IN_STANDARD_DEVICE &&
request->request == USB_REQUEST_GET_DESCRIPTOR)
{
const uint8_t type = request->value >> 8;
const uint8_t index = request->value;
switch (type)
{
case USB_DESCRIPTOR_DEVICE:
if (index == 0)
{
response = l_deviceDescriptor;
responseSize = sizeof(l_deviceDescriptor);
}
break;
case USB_DESCRIPTOR_CONFIGURATION:
if (index == 0)
{
response = l_configurationDescriptor;
responseSize = sizeof(l_configurationDescriptor);
}
break;
case USB_DESCRIPTOR_STRING:
responseSize = stringDescriptor(index, buffer, sizeof(buffer));
if (responseSize)
response = buffer;
break;
case USB_DESCRIPTOR_DEVICE_QUALIFIER:
if (index == 0)
{
response = l_deviceQualifierDescriptor;
responseSize = sizeof(l_deviceQualifierDescriptor);
}
break;
case USB_DESCRIPTOR_OTHER_SPEED:
if (index == 0)
{
/* Full-speed USB cannot carry the maximum PCM24 stream. Expose a
* functional stereo alternate sized for rates through 96 kHz. */
const size_t playbackControlSize =
USB_AUDIO_CONFIGURATION_DESC_SIZE +
USB_AUDIO_FUNCTION_CONTROL_SIZE;
memcpy(buffer, l_configurationDescriptor,
playbackControlSize);
size_t offset = playbackControlSize;
memcpy(buffer + offset, l_fullSpeedPlaybackDescriptor,
sizeof(l_fullSpeedPlaybackDescriptor));
offset += sizeof(l_fullSpeedPlaybackDescriptor);
memcpy(buffer + offset,
l_configurationDescriptor +
USB_AUDIO_RECORD_FUNCTION_OFFSET,
USB_AUDIO_FUNCTION_CONTROL_SIZE);
offset += USB_AUDIO_FUNCTION_CONTROL_SIZE;
memcpy(buffer + offset, l_fullSpeedRecordDescriptor,
sizeof(l_fullSpeedRecordDescriptor));
buffer[1] = USB_DESCRIPTOR_OTHER_SPEED;
buffer[2] = USB_AUDIO_OTHER_SPEED_SIZE & 0xff;
buffer[3] = USB_AUDIO_OTHER_SPEED_SIZE >> 8;
response = buffer;
responseSize = USB_AUDIO_OTHER_SPEED_SIZE;
}
break;
}
if (response)
status = usb_redir_success;
}
else if (request->request == USB_REQUEST_GET_STATUS &&
request->value == 0 && request->length == sizeof(l_zeroStatus))
{
bool valid = false;
switch (request->requesttype)
{
case USB_REQUEST_TYPE_IN_STANDARD_DEVICE:
valid = request->index == 0;
break;
case USB_REQUEST_TYPE_IN_STANDARD_INTERFACE:
valid = audio->configuration == USB_AUDIO_CONFIGURATION &&
(request->index == USB_AUDIO_PLAYBACK_CONTROL_IFACE ||
request->index == USB_AUDIO_PLAYBACK_IFACE ||
request->index == USB_AUDIO_RECORD_CONTROL_IFACE ||
request->index == USB_AUDIO_RECORD_IFACE);
break;
case USB_REQUEST_TYPE_IN_STANDARD_ENDPOINT:
valid = request->index == 0x00 || request->index == 0x80 ||
(audio->configuration == USB_AUDIO_CONFIGURATION &&
((getLayout(audio->playbackAlt) &&
(request->index == USB_AUDIO_PLAYBACK_DATA_ENDPOINT ||
request->index == USB_AUDIO_FEEDBACK_ENDPOINT)) ||
(audio->recordAlt == 1 &&
request->index == USB_AUDIO_RECORD_DATA_ENDPOINT)));
break;
}
if (valid)
{
response = l_zeroStatus;
responseSize = sizeof(l_zeroStatus);
status = usb_redir_success;
}
}
else if (audio->configuration == USB_AUDIO_CONFIGURATION &&
request->requesttype == USB_REQUEST_TYPE_IN_CLASS_INTERFACE &&
(request->index ==
((USB_AUDIO_PLAYBACK_CLOCK_ID << 8) |
USB_AUDIO_PLAYBACK_CONTROL_IFACE) ||
request->index ==
((USB_AUDIO_RECORD_CLOCK_ID << 8) |
USB_AUDIO_RECORD_CONTROL_IFACE)) &&
(uint8_t)request->value == 0)
{
const bool playbackClock = request->index ==
((USB_AUDIO_PLAYBACK_CLOCK_ID << 8) |
USB_AUDIO_PLAYBACK_CONTROL_IFACE);
const uint8_t control = request->value >> 8;
if (request->request == USB_REQUEST_CUR &&
control == USB_AUDIO_CONTROL_FREQUENCY)
{
writeLE32(buffer, playbackClock ?
audio->playbackSampleRate : atomic_load_explicit(
&audio->recordSampleRate, memory_order_relaxed));
response = buffer;
responseSize = 4;
status = usb_redir_success;
}
else if (request->request == USB_REQUEST_RANGE &&
control == USB_AUDIO_CONTROL_FREQUENCY)
{
responseSize = writeSampleRateRange(buffer);
response = buffer;
status = usb_redir_success;
}
else if (request->request == USB_REQUEST_CUR &&
control == USB_AUDIO_CONTROL_VALIDITY)
{
response = l_clockValid;
responseSize = sizeof(l_clockValid);
status = usb_redir_success;
}
}
else if (audio->configuration == USB_AUDIO_CONFIGURATION &&
request->requesttype == USB_REQUEST_TYPE_OUT_CLASS_INTERFACE &&
request->request == USB_REQUEST_CUR &&
(request->index ==
((USB_AUDIO_PLAYBACK_CLOCK_ID << 8) |
USB_AUDIO_PLAYBACK_CONTROL_IFACE) ||
request->index ==
((USB_AUDIO_RECORD_CLOCK_ID << 8) |
USB_AUDIO_RECORD_CONTROL_IFACE)) &&
request->value == (USB_AUDIO_CONTROL_FREQUENCY << 8) &&
request->length == 4 && dataLength == 4 && data)
{
const uint32_t sampleRate = nearestSampleRate(readLE32(data));
if (request->index ==
((USB_AUDIO_PLAYBACK_CLOCK_ID << 8) |
USB_AUDIO_PLAYBACK_CONTROL_IFACE))
setPlaybackSampleRate(audio, sampleRate);
else
setRecordSampleRate(audio, sampleRate);
status = usb_redir_success;
}
sendControlResponse(audio, id, request, status, response, responseSize);
if (data)
usbredirparser_free_packet_data(audio->parser, data);
}
static void isoPacket(void * opaque, uint64_t id,
struct usb_redir_iso_packet_header * packet,
uint8_t * data, int dataLength)
{
(void)id;
LG_USBAudio * audio = getAudio(opaque);
const USBAudioLayout * layout = getLayout(audio->playbackAlt);
if (audio->playbackStreaming)
{
const uint16_t frameSize =
layout ? layout->channelCount * USB_AUDIO_SAMPLE_SIZE : 0;
if (packet->endpoint != USB_AUDIO_PLAYBACK_DATA_ENDPOINT || !layout)
{
++audio->playbackInvalidPackets;
if (!audio->playbackErrorWarned)
{
DEBUG_WARN("USB audio packet loss detected; "
"keeping the playback stream active");
audio->playbackErrorWarned = true;
}
}
else
{
const uint32_t expectedFrames = nextPlaybackPacketFrames(audio);
const bool valid = packet->status == usb_redir_success &&
dataLength > 0 && packet->length == dataLength && data &&
dataLength <= layoutPacketSize(layout) &&
dataLength % frameSize == 0;
if (valid)
queuePlaybackPacket(
audio, data, dataLength / frameSize, frameSize);
else
{
if (packet->status == usb_redir_success)
++audio->playbackInvalidPackets;
++audio->playbackConcealedPackets;
queuePlaybackPacket(audio, NULL, expectedFrames, frameSize);
if (!audio->playbackErrorWarned)
{
DEBUG_WARN("USB audio packet loss detected; "
"keeping the playback stream active");
audio->playbackErrorWarned = true;
}
}
if (audio->playbackBatchPackets == USB_AUDIO_PLAYBACK_BATCH_PACKETS)
flushPlayback(audio);
}
}
if (data)
usbredirparser_free_packet_data(audio->parser, data);
}
static void setupDevice(void * opaque, struct usbredirparser * parser)
{
LG_USBAudio * audio = opaque;
audio->parser = parser;
parser->reset_func = resetUSB;
parser->set_configuration_func = setConfiguration;
parser->get_configuration_func = getConfiguration;
parser->set_alt_setting_func = setAltSetting;
parser->get_alt_setting_func = getAltSetting;
parser->start_iso_stream_func = startISOStream;
parser->stop_iso_stream_func = stopISOStream;
parser->cancel_data_packet_func = cancelDataPacket;
parser->control_packet_func = controlPacket;
parser->iso_packet_func = isoPacket;
}
static void plugDevice(void * opaque, struct usbredirparser * parser)
{
LG_USBAudio * audio = opaque;
audio->parser = parser;
resetDevice(audio);
sendDeviceInfo(audio);
struct usb_redir_device_connect_header device =
{
.speed = usb_redir_speed_high,
.device_class = 0xef,
.device_subclass = 0x02,
.device_protocol = 0x01,
.vendor_id = USB_AUDIO_VENDOR_ID,
.product_id = USB_AUDIO_PRODUCT_ID,
.device_version_bcd = USB_AUDIO_DEVICE_VERSION,
};
usbredirparser_send_device_connect(audio->parser, &device);
}
static void unplugDevice(void * opaque)
{
resetDevice(opaque);
}
static void reportRecordDebug(LG_USBAudio * audio)
{
if (!audio->debug)
return;
const uint64_t now = streamTime();
if (!audio->recordNextDebugTime)
{
audio->recordNextDebugTime =
now + USB_AUDIO_RECORD_DEBUG_INTERVAL_NS;
return;
}
if (now < audio->recordNextDebugTime)
return;
audio->recordNextDebugTime = now + USB_AUDIO_RECORD_DEBUG_INTERVAL_NS;
const uint_fast64_t overflow = atomic_exchange_explicit(
&audio->recordOverflowFrames, 0, memory_order_relaxed);
const uint_fast64_t underflow = atomic_exchange_explicit(
&audio->recordUnderflowFrames, 0, memory_order_relaxed);
const uint_fast64_t trimmed = atomic_exchange_explicit(
&audio->recordTrimmedFrames, 0, memory_order_relaxed);
const uint_fast64_t late = atomic_exchange_explicit(
&audio->recordLatePackets, 0, memory_order_relaxed);
const uint_fast64_t maxLateness = atomic_exchange_explicit(
&audio->recordMaxLateness, 0, memory_order_relaxed);
const uint_fast64_t discontinuities = atomic_exchange_explicit(
&audio->recordDiscontinuities, 0, memory_order_relaxed);
if (!overflow && !underflow && !trimmed && !late && !discontinuities)
return;
DEBUG_INFO(
"USB capture: overflow %" PRIuFAST64
", underflow %" PRIuFAST64
", trimmed %" PRIuFAST64
" frames; late %" PRIuFAST64
" packets, max %.3f ms, discontinuities %" PRIuFAST64,
overflow, underflow, trimmed, late, maxLateness / 1000000.0,
discontinuities);
}
static void reportPlaybackDebug(LG_USBAudio * audio)
{
if (!audio->debug)
return;
const uint64_t now = streamTime();
if (!audio->playbackNextDebugTime)
{
audio->playbackNextDebugTime =
now + USB_AUDIO_PLAYBACK_DEBUG_INTERVAL_NS;
return;
}
if (now < audio->playbackNextDebugTime)
return;
audio->playbackNextDebugTime =
now + USB_AUDIO_PLAYBACK_DEBUG_INTERVAL_NS;
if (!audio->playbackConcealedPackets &&
!audio->playbackInvalidPackets)
return;
DEBUG_INFO("USB playback: concealed %" PRIu64
" packets, invalid %" PRIu64,
audio->playbackConcealedPackets,
audio->playbackInvalidPackets);
audio->playbackConcealedPackets = 0;
audio->playbackInvalidPackets = 0;
}
static void processDevice(void * opaque, bool writable)
{
LG_USBAudio * audio = opaque;
const uint64_t now = streamTime();
if (!writable)
{
if (atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
audio->recordNextPacketTime =
now + USB_AUDIO_RECORD_PACKET_INTERVAL_NS;
audio->outputBackpressured = true;
}
else if (audio->outputBackpressured)
{
audio->recordNextPacketTime =
now + USB_AUDIO_RECORD_PACKET_INTERVAL_NS;
audio->outputBackpressured = false;
}
if (writable)
sendFeedbackPacketsDue(audio);
flushPlayback(audio);
if (writable)
sendRecordPackets(audio);
reportPlaybackDebug(audio);
reportRecordDebug(audio);
}
static const LG_USBRedirDeviceOps l_deviceOps =
{
.setup = setupDevice,
.plug = plugDevice,
.process = processDevice,
.unplug = unplugDevice,
};
LG_USBAudio * lgUsbAudio_create(const LG_USBAudioEventOps * events,
void * eventOpaque, bool debug)
{
LG_USBAudio * audio = calloc(1, sizeof(*audio));
if (!audio)
return NULL;
audio->events = events;
audio->eventOpaque = eventOpaque;
audio->debug = debug;
audio->playbackSampleRate = LG_USB_AUDIO_DEFAULT_SAMPLE_RATE;
audio->recordBatchPackets = 1;
audio->recordSafetyPackets = 1;
audio->recordIdle = lgCreateEvent(true, 0);
if (!audio->recordIdle)
{
free(audio);
return NULL;
}
audio->recordBuffer = ringbuffer_new(
USB_AUDIO_RECORD_QUEUE_FRAMES, USB_AUDIO_RECORD_FRAME_SIZE);
if (!audio->recordBuffer)
{
lgFreeEvent(audio->recordIdle);
free(audio);
return NULL;
}
atomic_init(&audio->feedbackValue,
encodeFeedbackRate(audio->playbackSampleRate));
atomic_init(&audio->feedbackStreaming, false);
atomic_init(
&audio->recordSampleRate, LG_USB_AUDIO_DEFAULT_SAMPLE_RATE);
atomic_init(&audio->recordStreaming, false);
atomic_init(&audio->recordAccepting, false);
atomic_init(&audio->recordOverflowPending, false);
atomic_init(&audio->recordGeneration, 0);
atomic_init(&audio->recordInFlight, 0);
atomic_init(&audio->recordRateQ16,
(uint64_t)LG_USB_AUDIO_DEFAULT_SAMPLE_RATE *
USB_AUDIO_RECORD_RATE_SCALE);
atomic_init(&audio->recordOverflowFrames, 0);
atomic_init(&audio->recordUnderflowFrames, 0);
atomic_init(&audio->recordTrimmedFrames, 0);
atomic_init(&audio->recordLatePackets, 0);
atomic_init(&audio->recordMaxLateness, 0);
atomic_init(&audio->recordDiscontinuities, 0);
return audio;
}
void lgUsbAudio_setFeedbackRate(LG_USBAudio * audio, double sampleRate)
{
if (!audio)
return;
atomic_store_explicit(&audio->feedbackValue,
encodeFeedbackRate(sampleRate), memory_order_release);
}
bool lgUsbAudio_feedbackActive(const LG_USBAudio * audio)
{
return audio && atomic_load_explicit(
&audio->feedbackStreaming, memory_order_acquire);
}
bool lgUsbAudio_recordData(
LG_USBAudio * audio, const void * data, size_t frames,
const LG_AudioClock * sourceClock)
{
if (!audio || frames > INT_MAX || (frames && !data))
return false;
const unsigned int generation = atomic_load_explicit(
&audio->recordGeneration, memory_order_seq_cst);
if (!atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire) ||
!atomic_load_explicit(
&audio->recordAccepting, memory_order_seq_cst))
return false;
atomic_fetch_add_explicit(
&audio->recordInFlight, 1, memory_order_seq_cst);
if (!atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire) ||
!atomic_load_explicit(
&audio->recordAccepting, memory_order_seq_cst) ||
atomic_load_explicit(
&audio->recordGeneration, memory_order_seq_cst) != generation)
{
const unsigned int previous = atomic_fetch_sub_explicit(
&audio->recordInFlight, 1, memory_order_seq_cst);
if (previous == 1 && !atomic_load_explicit(
&audio->recordAccepting, memory_order_seq_cst))
lgSignalEvent(audio->recordIdle);
return false;
}
const size_t receivedFrames = frames;
const uint32_t sampleRate = atomic_load_explicit(
&audio->recordSampleRate, memory_order_relaxed);
bool sourceContinuous = true;
if (sourceClock)
sourceContinuous = updateRecordSourceRate(
audio, sampleRate, sourceClock);
else
updateRecordArrivalRate(audio, sampleRate, receivedFrames);
size_t overflowFrames = 0;
if (sourceContinuous)
{
const int length = ringbuffer_getLength(audio->recordBuffer);
const uint8_t * input = data;
if (frames > (size_t)length)
{
input += (frames - length) * USB_AUDIO_RECORD_FRAME_SIZE;
frames = length;
}
const int appended = ringbuffer_append(
audio->recordBuffer, input, (int)frames);
overflowFrames = receivedFrames - appended;
}
if (!sourceContinuous || overflowFrames)
{
atomic_store_explicit(
&audio->recordOverflowPending, true, memory_order_release);
if (audio->debug)
atomic_fetch_add_explicit(&audio->recordOverflowFrames,
overflowFrames, memory_order_relaxed);
}
const unsigned int previous = atomic_fetch_sub_explicit(
&audio->recordInFlight, 1, memory_order_seq_cst);
if (previous == 1 && !atomic_load_explicit(
&audio->recordAccepting, memory_order_seq_cst))
lgSignalEvent(audio->recordIdle);
return !sourceContinuous || !overflowFrames;
}
uint64_t lgUsbAudio_processDelayNs(const LG_USBAudio * audio)
{
if (!audio)
return UINT64_MAX;
if (audio->outputBackpressured)
return UINT64_MAX;
const uint64_t now = streamTime();
uint64_t delay = UINT64_MAX;
if (atomic_load_explicit(
&audio->feedbackStreaming, memory_order_acquire))
delay = audio->feedbackNextPacketTime > now ?
audio->feedbackNextPacketTime - now : 0;
if (!atomic_load_explicit(
&audio->recordStreaming, memory_order_acquire))
return delay;
uint64_t recordDelay = 0;
if (!audio->recordRefillPackets)
{
const uint64_t deadline = audio->recordNextPacketTime +
(uint64_t)(audio->recordBatchPackets - 1) *
USB_AUDIO_RECORD_PACKET_INTERVAL_NS;
recordDelay = deadline > now ? deadline - now : 0;
}
return min(delay, recordDelay);
}
void lgUsbAudio_destroy(LG_USBAudio * audio)
{
if (!audio)
return;
recordDisableInput(audio);
recordWaitForInput(audio);
ringbuffer_free(&audio->recordBuffer);
lgFreeEvent(audio->recordIdle);
free(audio);
}
const LG_USBRedirDeviceOps * lgUsbAudio_deviceOps(void)
{
return &l_deviceOps;
}
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