qemu/audio/paaudio.c

/* public domain */

#include "qemu/osdep.h"
#include "qemu/module.h"
#include "audio.h"
#include "qapi/opts-visitor.h"

#include <pulse/pulseaudio.h>

#define AUDIO_CAP "pulseaudio"
#include "audio_int.h"
#include "audio_pt_int.h"

typedef struct PAConnection {
    char *server;
    int refcount;
    QTAILQ_ENTRY(PAConnection) list;

    pa_threaded_mainloop *mainloop;
    pa_context *context;
} PAConnection;

static QTAILQ_HEAD(PAConnectionHead, PAConnection) pa_conns =
    QTAILQ_HEAD_INITIALIZER(pa_conns);

typedef struct {
    Audiodev *dev;
    PAConnection *conn;
} paaudio;

typedef struct {
    HWVoiceOut hw;
    int done;
    int live;
    int decr;
    int rpos;
    pa_stream *stream;
    void *pcm_buf;
    struct audio_pt pt;
    paaudio *g;
    int samples;
} PAVoiceOut;

typedef struct {
    HWVoiceIn hw;
    int done;
    int dead;
    int incr;
    int wpos;
    pa_stream *stream;
    void *pcm_buf;
    struct audio_pt pt;
    const void *read_data;
    size_t read_index, read_length;
    paaudio *g;
    int samples;
} PAVoiceIn;

static void qpa_conn_fini(PAConnection *c);

static void GCC_FMT_ATTR (2, 3) qpa_logerr (int err, const char *fmt, ...)
{
    va_list ap;

    va_start (ap, fmt);
    AUD_vlog (AUDIO_CAP, fmt, ap);
    va_end (ap);

    AUD_log (AUDIO_CAP, "Reason: %s\n", pa_strerror (err));
}

#ifndef PA_CONTEXT_IS_GOOD
static inline int PA_CONTEXT_IS_GOOD(pa_context_state_t x)
{
    return
        x == PA_CONTEXT_CONNECTING ||
        x == PA_CONTEXT_AUTHORIZING ||
        x == PA_CONTEXT_SETTING_NAME ||
        x == PA_CONTEXT_READY;
}
#endif

#ifndef PA_STREAM_IS_GOOD
static inline int PA_STREAM_IS_GOOD(pa_stream_state_t x)
{
    return
        x == PA_STREAM_CREATING ||
        x == PA_STREAM_READY;
}
#endif

#define CHECK_SUCCESS_GOTO(c, rerror, expression, label)        \
    do {                                                        \
        if (!(expression)) {                                    \
            if (rerror) {                                       \
                *(rerror) = pa_context_errno ((c)->context);    \
            }                                                   \
            goto label;                                         \
        }                                                       \
    } while (0)

#define CHECK_DEAD_GOTO(c, stream, rerror, label)                       \
    do {                                                                \
        if (!(c)->context || !PA_CONTEXT_IS_GOOD (pa_context_get_state((c)->context)) || \
            !(stream) || !PA_STREAM_IS_GOOD (pa_stream_get_state ((stream)))) { \
            if (((c)->context && pa_context_get_state ((c)->context) == PA_CONTEXT_FAILED) || \
                ((stream) && pa_stream_get_state ((stream)) == PA_STREAM_FAILED)) { \
                if (rerror) {                                           \
                    *(rerror) = pa_context_errno ((c)->context);        \
                }                                                       \
            } else {                                                    \
                if (rerror) {                                           \
                    *(rerror) = PA_ERR_BADSTATE;                        \
                }                                                       \
            }                                                           \
            goto label;                                                 \
        }                                                               \
    } while (0)

static int qpa_simple_read (PAVoiceIn *p, void *data, size_t length, int *rerror)
{
    PAConnection *c = p->g->conn;

    pa_threaded_mainloop_lock(c->mainloop);

    CHECK_DEAD_GOTO(c, p->stream, rerror, unlock_and_fail);

    while (length > 0) {
        size_t l;

        while (!p->read_data) {
            int r;

            r = pa_stream_peek (p->stream, &p->read_data, &p->read_length);
            CHECK_SUCCESS_GOTO(c, rerror, r == 0, unlock_and_fail);

            if (!p->read_data) {
                pa_threaded_mainloop_wait(c->mainloop);
                CHECK_DEAD_GOTO(c, p->stream, rerror, unlock_and_fail);
            } else {
                p->read_index = 0;
            }
        }

        l = p->read_length < length ? p->read_length : length;
        memcpy (data, (const uint8_t *) p->read_data+p->read_index, l);

        data = (uint8_t *) data + l;
        length -= l;

        p->read_index += l;
        p->read_length -= l;

        if (!p->read_length) {
            int r;

            r = pa_stream_drop (p->stream);
            p->read_data = NULL;
            p->read_length = 0;
            p->read_index = 0;

            CHECK_SUCCESS_GOTO(c, rerror, r == 0, unlock_and_fail);
        }
    }

    pa_threaded_mainloop_unlock(c->mainloop);
    return 0;

unlock_and_fail:
    pa_threaded_mainloop_unlock(c->mainloop);
    return -1;
}

static int qpa_simple_write (PAVoiceOut *p, const void *data, size_t length, int *rerror)
{
    PAConnection *c = p->g->conn;

    pa_threaded_mainloop_lock(c->mainloop);

    CHECK_DEAD_GOTO(c, p->stream, rerror, unlock_and_fail);

    while (length > 0) {
        size_t l;
        int r;

        while (!(l = pa_stream_writable_size (p->stream))) {
            pa_threaded_mainloop_wait(c->mainloop);
            CHECK_DEAD_GOTO(c, p->stream, rerror, unlock_and_fail);
        }

        CHECK_SUCCESS_GOTO(c, rerror, l != (size_t) -1, unlock_and_fail);

        if (l > length) {
            l = length;
        }

        r = pa_stream_write (p->stream, data, l, NULL, 0LL, PA_SEEK_RELATIVE);
        CHECK_SUCCESS_GOTO(c, rerror, r >= 0, unlock_and_fail);

        data = (const uint8_t *) data + l;
        length -= l;
    }

    pa_threaded_mainloop_unlock(c->mainloop);
    return 0;

unlock_and_fail:
    pa_threaded_mainloop_unlock(c->mainloop);
    return -1;
}

static void *qpa_thread_out (void *arg)
{
    PAVoiceOut *pa = arg;
    HWVoiceOut *hw = &pa->hw;

    if (audio_pt_lock(&pa->pt, __func__)) {
        return NULL;
    }

    for (;;) {
        int decr, to_mix, rpos;

        for (;;) {
            if (pa->done) {
                goto exit;
            }

            if (pa->live > 0) {
                break;
            }

            if (audio_pt_wait(&pa->pt, __func__)) {
                goto exit;
            }
        }

        decr = to_mix = audio_MIN(pa->live, pa->samples >> 5);
        rpos = pa->rpos;

        if (audio_pt_unlock(&pa->pt, __func__)) {
            return NULL;
        }

        while (to_mix) {
            int error;
            int chunk = audio_MIN (to_mix, hw->samples - rpos);
            struct st_sample *src = hw->mix_buf + rpos;

            hw->clip (pa->pcm_buf, src, chunk);

            if (qpa_simple_write (pa, pa->pcm_buf,
                                  chunk << hw->info.shift, &error) < 0) {
                qpa_logerr (error, "pa_simple_write failed\n");
                return NULL;
            }

            rpos = (rpos + chunk) % hw->samples;
            to_mix -= chunk;
        }

        if (audio_pt_lock(&pa->pt, __func__)) {
            return NULL;
        }

        pa->rpos = rpos;
        pa->live -= decr;
        pa->decr += decr;
    }

 exit:
    audio_pt_unlock(&pa->pt, __func__);
    return NULL;
}

static int qpa_run_out (HWVoiceOut *hw, int live)
{
    int decr;
    PAVoiceOut *pa = (PAVoiceOut *) hw;

    if (audio_pt_lock(&pa->pt, __func__)) {
        return 0;
    }

    decr = audio_MIN (live, pa->decr);
    pa->decr -= decr;
    pa->live = live - decr;
    hw->rpos = pa->rpos;
    if (pa->live > 0) {
        audio_pt_unlock_and_signal(&pa->pt, __func__);
    }
    else {
        audio_pt_unlock(&pa->pt, __func__);
    }
    return decr;
}

static int qpa_write (SWVoiceOut *sw, void *buf, int len)
{
    return audio_pcm_sw_write (sw, buf, len);
}

/* capture */
static void *qpa_thread_in (void *arg)
{
    PAVoiceIn *pa = arg;
    HWVoiceIn *hw = &pa->hw;

    if (audio_pt_lock(&pa->pt, __func__)) {
        return NULL;
    }

    for (;;) {
        int incr, to_grab, wpos;

        for (;;) {
            if (pa->done) {
                goto exit;
            }

            if (pa->dead > 0) {
                break;
            }

            if (audio_pt_wait(&pa->pt, __func__)) {
                goto exit;
            }
        }

        incr = to_grab = audio_MIN(pa->dead, pa->samples >> 5);
        wpos = pa->wpos;

        if (audio_pt_unlock(&pa->pt, __func__)) {
            return NULL;
        }

        while (to_grab) {
            int error;
            int chunk = audio_MIN (to_grab, hw->samples - wpos);
            void *buf = advance (pa->pcm_buf, wpos);

            if (qpa_simple_read (pa, buf,
                                 chunk << hw->info.shift, &error) < 0) {
                qpa_logerr (error, "pa_simple_read failed\n");
                return NULL;
            }

            hw->conv (hw->conv_buf + wpos, buf, chunk);
            wpos = (wpos + chunk) % hw->samples;
            to_grab -= chunk;
        }

        if (audio_pt_lock(&pa->pt, __func__)) {
            return NULL;
        }

        pa->wpos = wpos;
        pa->dead -= incr;
        pa->incr += incr;
    }

 exit:
    audio_pt_unlock(&pa->pt, __func__);
    return NULL;
}

static int qpa_run_in (HWVoiceIn *hw)
{
    int live, incr, dead;
    PAVoiceIn *pa = (PAVoiceIn *) hw;

    if (audio_pt_lock(&pa->pt, __func__)) {
        return 0;
    }

    live = audio_pcm_hw_get_live_in (hw);
    dead = hw->samples - live;
    incr = audio_MIN (dead, pa->incr);
    pa->incr -= incr;
    pa->dead = dead - incr;
    hw->wpos = pa->wpos;
    if (pa->dead > 0) {
        audio_pt_unlock_and_signal(&pa->pt, __func__);
    }
    else {
        audio_pt_unlock(&pa->pt, __func__);
    }
    return incr;
}

static int qpa_read (SWVoiceIn *sw, void *buf, int len)
{
    return audio_pcm_sw_read (sw, buf, len);
}

static pa_sample_format_t audfmt_to_pa (AudioFormat afmt, int endianness)
{
    int format;

    switch (afmt) {
    case AUDIO_FORMAT_S8:
    case AUDIO_FORMAT_U8:
        format = PA_SAMPLE_U8;
        break;
    case AUDIO_FORMAT_S16:
    case AUDIO_FORMAT_U16:
        format = endianness ? PA_SAMPLE_S16BE : PA_SAMPLE_S16LE;
        break;
    case AUDIO_FORMAT_S32:
    case AUDIO_FORMAT_U32:
        format = endianness ? PA_SAMPLE_S32BE : PA_SAMPLE_S32LE;
        break;
    default:
        dolog ("Internal logic error: Bad audio format %d\n", afmt);
        format = PA_SAMPLE_U8;
        break;
    }
    return format;
}

static AudioFormat pa_to_audfmt (pa_sample_format_t fmt, int *endianness)
{
    switch (fmt) {
    case PA_SAMPLE_U8:
        return AUDIO_FORMAT_U8;
    case PA_SAMPLE_S16BE:
        *endianness = 1;
        return AUDIO_FORMAT_S16;
    case PA_SAMPLE_S16LE:
        *endianness = 0;
        return AUDIO_FORMAT_S16;
    case PA_SAMPLE_S32BE:
        *endianness = 1;
        return AUDIO_FORMAT_S32;
    case PA_SAMPLE_S32LE:
        *endianness = 0;
        return AUDIO_FORMAT_S32;
    default:
        dolog ("Internal logic error: Bad pa_sample_format %d\n", fmt);
        return AUDIO_FORMAT_U8;
    }
}

static void context_state_cb (pa_context *c, void *userdata)
{
    PAConnection *conn = userdata;

    switch (pa_context_get_state(c)) {
    case PA_CONTEXT_READY:
    case PA_CONTEXT_TERMINATED:
    case PA_CONTEXT_FAILED:
        pa_threaded_mainloop_signal(conn->mainloop, 0);
        break;

    case PA_CONTEXT_UNCONNECTED:
    case PA_CONTEXT_CONNECTING:
    case PA_CONTEXT_AUTHORIZING:
    case PA_CONTEXT_SETTING_NAME:
        break;
    }
}

static void stream_state_cb (pa_stream *s, void * userdata)
{
    PAConnection *c = userdata;

    switch (pa_stream_get_state (s)) {

    case PA_STREAM_READY:
    case PA_STREAM_FAILED:
    case PA_STREAM_TERMINATED:
        pa_threaded_mainloop_signal(c->mainloop, 0);
        break;

    case PA_STREAM_UNCONNECTED:
    case PA_STREAM_CREATING:
        break;
    }
}

static void stream_request_cb (pa_stream *s, size_t length, void *userdata)
{
    PAConnection *c = userdata;

    pa_threaded_mainloop_signal(c->mainloop, 0);
}

static pa_stream *qpa_simple_new (
        PAConnection *c,
        const char *name,
        pa_stream_direction_t dir,
        const char *dev,
        const pa_sample_spec *ss,
        const pa_channel_map *map,
        const pa_buffer_attr *attr,
        int *rerror)
{
    int r;
    pa_stream *stream;
    pa_stream_flags_t flags;

    pa_threaded_mainloop_lock(c->mainloop);

    stream = pa_stream_new(c->context, name, ss, map);
    if (!stream) {
        goto fail;
    }

    pa_stream_set_state_callback(stream, stream_state_cb, c);
    pa_stream_set_read_callback(stream, stream_request_cb, c);
    pa_stream_set_write_callback(stream, stream_request_cb, c);

    flags =
        PA_STREAM_INTERPOLATE_TIMING
#ifdef PA_STREAM_ADJUST_LATENCY
        | PA_STREAM_ADJUST_LATENCY
#endif
        | PA_STREAM_AUTO_TIMING_UPDATE;

    if (dev) {
        /* don't move the stream if the user specified a sink/source */
        flags |= PA_STREAM_DONT_MOVE;
    }

    if (dir == PA_STREAM_PLAYBACK) {
        r = pa_stream_connect_playback(stream, dev, attr, flags, NULL, NULL);
    } else {
        r = pa_stream_connect_record(stream, dev, attr, flags);
    }

    if (r < 0) {
      goto fail;
    }

    pa_threaded_mainloop_unlock(c->mainloop);

    return stream;

fail:
    pa_threaded_mainloop_unlock(c->mainloop);

    if (stream) {
        pa_stream_unref (stream);
    }

    *rerror = pa_context_errno(c->context);

    return NULL;
}

static int qpa_init_out(HWVoiceOut *hw, struct audsettings *as,
                        void *drv_opaque)
{
    int error;
    pa_sample_spec ss;
    pa_buffer_attr ba;
    struct audsettings obt_as = *as;
    PAVoiceOut *pa = (PAVoiceOut *) hw;
    paaudio *g = pa->g = drv_opaque;
    AudiodevPaOptions *popts = &g->dev->u.pa;
    AudiodevPaPerDirectionOptions *ppdo = popts->out;
    PAConnection *c = g->conn;

    ss.format = audfmt_to_pa (as->fmt, as->endianness);
    ss.channels = as->nchannels;
    ss.rate = as->freq;

    ba.tlength = pa_usec_to_bytes(ppdo->latency, &ss);
    ba.minreq = -1;
    ba.maxlength = -1;
    ba.prebuf = -1;

    obt_as.fmt = pa_to_audfmt (ss.format, &obt_as.endianness);

    pa->stream = qpa_simple_new (
        c,
        "qemu",
        PA_STREAM_PLAYBACK,
        ppdo->has_name ? ppdo->name : NULL,
        &ss,
        NULL,                   /* channel map */
        &ba,                    /* buffering attributes */
        &error
        );
    if (!pa->stream) {
        qpa_logerr (error, "pa_simple_new for playback failed\n");
        goto fail1;
    }

    audio_pcm_init_info (&hw->info, &obt_as);
    hw->samples = pa->samples = audio_buffer_samples(
        qapi_AudiodevPaPerDirectionOptions_base(ppdo),
        &obt_as, ppdo->buffer_length);
    pa->pcm_buf = audio_calloc(__func__, hw->samples, 1 << hw->info.shift);
    pa->rpos = hw->rpos;
    if (!pa->pcm_buf) {
        dolog ("Could not allocate buffer (%d bytes)\n",
               hw->samples << hw->info.shift);
        goto fail2;
    }

    if (audio_pt_init(&pa->pt, qpa_thread_out, hw, AUDIO_CAP, __func__)) {
        goto fail3;
    }

    return 0;

 fail3:
    g_free (pa->pcm_buf);
    pa->pcm_buf = NULL;
 fail2:
    if (pa->stream) {
        pa_stream_unref (pa->stream);
        pa->stream = NULL;
    }
 fail1:
    return -1;
}

static int qpa_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
{
    int error;
    pa_sample_spec ss;
    pa_buffer_attr ba;
    struct audsettings obt_as = *as;
    PAVoiceIn *pa = (PAVoiceIn *) hw;
    paaudio *g = pa->g = drv_opaque;
    AudiodevPaOptions *popts = &g->dev->u.pa;
    AudiodevPaPerDirectionOptions *ppdo = popts->in;
    PAConnection *c = g->conn;

    ss.format = audfmt_to_pa (as->fmt, as->endianness);
    ss.channels = as->nchannels;
    ss.rate = as->freq;

    ba.fragsize = pa_usec_to_bytes(ppdo->latency, &ss);
    ba.maxlength = pa_usec_to_bytes(ppdo->latency * 2, &ss);
    ba.minreq = -1;
    ba.prebuf = -1;

    obt_as.fmt = pa_to_audfmt (ss.format, &obt_as.endianness);

    pa->stream = qpa_simple_new (
        c,
        "qemu",
        PA_STREAM_RECORD,
        ppdo->has_name ? ppdo->name : NULL,
        &ss,
        NULL,                   /* channel map */
        &ba,                    /* buffering attributes */
        &error
        );
    if (!pa->stream) {
        qpa_logerr (error, "pa_simple_new for capture failed\n");
        goto fail1;
    }

    audio_pcm_init_info (&hw->info, &obt_as);
    hw->samples = pa->samples = audio_buffer_samples(
        qapi_AudiodevPaPerDirectionOptions_base(ppdo),
        &obt_as, ppdo->buffer_length);
    pa->pcm_buf = audio_calloc(__func__, hw->samples, 1 << hw->info.shift);
    pa->wpos = hw->wpos;
    if (!pa->pcm_buf) {
        dolog ("Could not allocate buffer (%d bytes)\n",
               hw->samples << hw->info.shift);
        goto fail2;
    }

    if (audio_pt_init(&pa->pt, qpa_thread_in, hw, AUDIO_CAP, __func__)) {
        goto fail3;
    }

    return 0;

 fail3:
    g_free (pa->pcm_buf);
    pa->pcm_buf = NULL;
 fail2:
    if (pa->stream) {
        pa_stream_unref (pa->stream);
        pa->stream = NULL;
    }
 fail1:
    return -1;
}

static void qpa_fini_out (HWVoiceOut *hw)
{
    void *ret;
    PAVoiceOut *pa = (PAVoiceOut *) hw;

    audio_pt_lock(&pa->pt, __func__);
    pa->done = 1;
    audio_pt_unlock_and_signal(&pa->pt, __func__);
    audio_pt_join(&pa->pt, &ret, __func__);

    if (pa->stream) {
        pa_stream_unref (pa->stream);
        pa->stream = NULL;
    }

    audio_pt_fini(&pa->pt, __func__);
    g_free (pa->pcm_buf);
    pa->pcm_buf = NULL;
}

static void qpa_fini_in (HWVoiceIn *hw)
{
    void *ret;
    PAVoiceIn *pa = (PAVoiceIn *) hw;

    audio_pt_lock(&pa->pt, __func__);
    pa->done = 1;
    audio_pt_unlock_and_signal(&pa->pt, __func__);
    audio_pt_join(&pa->pt, &ret, __func__);

    if (pa->stream) {
        pa_stream_unref (pa->stream);
        pa->stream = NULL;
    }

    audio_pt_fini(&pa->pt, __func__);
    g_free (pa->pcm_buf);
    pa->pcm_buf = NULL;
}

static int qpa_ctl_out (HWVoiceOut *hw, int cmd, ...)
{
    PAVoiceOut *pa = (PAVoiceOut *) hw;
    pa_operation *op;
    pa_cvolume v;
    PAConnection *c = pa->g->conn;

#ifdef PA_CHECK_VERSION    /* macro is present in 0.9.16+ */
    pa_cvolume_init (&v);  /* function is present in 0.9.13+ */
#endif

    switch (cmd) {
    case VOICE_VOLUME:
        {
            SWVoiceOut *sw;
            va_list ap;

            va_start (ap, cmd);
            sw = va_arg (ap, SWVoiceOut *);
            va_end (ap);

            v.channels = 2;
            v.values[0] = ((PA_VOLUME_NORM - PA_VOLUME_MUTED) * sw->vol.l) / UINT32_MAX;
            v.values[1] = ((PA_VOLUME_NORM - PA_VOLUME_MUTED) * sw->vol.r) / UINT32_MAX;

            pa_threaded_mainloop_lock(c->mainloop);

            op = pa_context_set_sink_input_volume(c->context,
                pa_stream_get_index (pa->stream),
                &v, NULL, NULL);
            if (!op) {
                qpa_logerr(pa_context_errno(c->context),
                           "set_sink_input_volume() failed\n");
            } else {
                pa_operation_unref(op);
            }

            op = pa_context_set_sink_input_mute(c->context,
                pa_stream_get_index (pa->stream),
               sw->vol.mute, NULL, NULL);
            if (!op) {
                qpa_logerr(pa_context_errno(c->context),
                           "set_sink_input_mute() failed\n");
            } else {
                pa_operation_unref(op);
            }

            pa_threaded_mainloop_unlock(c->mainloop);
        }
    }
    return 0;
}

static int qpa_ctl_in (HWVoiceIn *hw, int cmd, ...)
{
    PAVoiceIn *pa = (PAVoiceIn *) hw;
    pa_operation *op;
    pa_cvolume v;
    PAConnection *c = pa->g->conn;

#ifdef PA_CHECK_VERSION
    pa_cvolume_init (&v);
#endif

    switch (cmd) {
    case VOICE_VOLUME:
        {
            SWVoiceIn *sw;
            va_list ap;

            va_start (ap, cmd);
            sw = va_arg (ap, SWVoiceIn *);
            va_end (ap);

            v.channels = 2;
            v.values[0] = ((PA_VOLUME_NORM - PA_VOLUME_MUTED) * sw->vol.l) / UINT32_MAX;
            v.values[1] = ((PA_VOLUME_NORM - PA_VOLUME_MUTED) * sw->vol.r) / UINT32_MAX;

            pa_threaded_mainloop_lock(c->mainloop);

            op = pa_context_set_source_output_volume(c->context,
                pa_stream_get_index(pa->stream),
                &v, NULL, NULL);
            if (!op) {
                qpa_logerr(pa_context_errno(c->context),
                           "set_source_output_volume() failed\n");
            } else {
                pa_operation_unref(op);
            }

            op = pa_context_set_source_output_mute(c->context,
                pa_stream_get_index (pa->stream),
                sw->vol.mute, NULL, NULL);
            if (!op) {
                qpa_logerr(pa_context_errno(c->context),
                           "set_source_output_mute() failed\n");
            } else {
                pa_operation_unref (op);
            }

            pa_threaded_mainloop_unlock(c->mainloop);
        }
    }
    return 0;
}

static int qpa_validate_per_direction_opts(Audiodev *dev,
                                           AudiodevPaPerDirectionOptions *pdo)
{
    if (!pdo->has_buffer_length) {
        pdo->has_buffer_length = true;
        pdo->buffer_length = 46440;
    }
    if (!pdo->has_latency) {
        pdo->has_latency = true;
        pdo->latency = 15000;
    }
    return 1;
}

/* common */
static void *qpa_conn_init(const char *server)
{
    PAConnection *c = g_malloc0(sizeof(PAConnection));
    QTAILQ_INSERT_TAIL(&pa_conns, c, list);

    c->mainloop = pa_threaded_mainloop_new();
    if (!c->mainloop) {
        goto fail;
    }

    c->context = pa_context_new(pa_threaded_mainloop_get_api(c->mainloop),
                                server);
    if (!c->context) {
        goto fail;
    }

    pa_context_set_state_callback(c->context, context_state_cb, c);

    if (pa_context_connect(c->context, server, 0, NULL) < 0) {
        qpa_logerr(pa_context_errno(c->context),
                   "pa_context_connect() failed\n");
        goto fail;
    }

    pa_threaded_mainloop_lock(c->mainloop);

    if (pa_threaded_mainloop_start(c->mainloop) < 0) {
        goto unlock_and_fail;
    }

    for (;;) {
        pa_context_state_t state;

        state = pa_context_get_state(c->context);

        if (state == PA_CONTEXT_READY) {
            break;
        }

        if (!PA_CONTEXT_IS_GOOD(state)) {
            qpa_logerr(pa_context_errno(c->context),
                       "Wrong context state\n");
            goto unlock_and_fail;
        }

        /* Wait until the context is ready */
        pa_threaded_mainloop_wait(c->mainloop);
    }

    pa_threaded_mainloop_unlock(c->mainloop);
    return c;

unlock_and_fail:
    pa_threaded_mainloop_unlock(c->mainloop);
fail:
    AUD_log (AUDIO_CAP, "Failed to initialize PA context");
    qpa_conn_fini(c);
    return NULL;
}

static void *qpa_audio_init(Audiodev *dev)
{
    paaudio *g;
    AudiodevPaOptions *popts = &dev->u.pa;
    const char *server;
    PAConnection *c;

    assert(dev->driver == AUDIODEV_DRIVER_PA);

    if (!popts->has_server) {
        char pidfile[64];
        char *runtime;
        struct stat st;

        runtime = getenv("XDG_RUNTIME_DIR");
        if (!runtime) {
            return NULL;
        }
        snprintf(pidfile, sizeof(pidfile), "%s/pulse/pid", runtime);
        if (stat(pidfile, &st) != 0) {
            return NULL;
        }
    }

    if (!qpa_validate_per_direction_opts(dev, popts->in)) {
        return NULL;
    }
    if (!qpa_validate_per_direction_opts(dev, popts->out)) {
        return NULL;
    }

    g = g_malloc0(sizeof(paaudio));
    server = popts->has_server ? popts->server : NULL;

    g->dev = dev;

    QTAILQ_FOREACH(c, &pa_conns, list) {
        if (server == NULL || c->server == NULL ?
            server == c->server :
            strcmp(server, c->server) == 0) {
            g->conn = c;
            break;
        }
    }
    if (!g->conn) {
        g->conn = qpa_conn_init(server);
    }
    if (!g->conn) {
        g_free(g);
        return NULL;
    }

    ++g->conn->refcount;
    return g;
}

static void qpa_conn_fini(PAConnection *c)
{
    if (c->mainloop) {
        pa_threaded_mainloop_stop(c->mainloop);
    }

    if (c->context) {
        pa_context_disconnect(c->context);
        pa_context_unref(c->context);
    }

    if (c->mainloop) {
        pa_threaded_mainloop_free(c->mainloop);
    }

    QTAILQ_REMOVE(&pa_conns, c, list);
    g_free(c);
}

static void qpa_audio_fini (void *opaque)
{
    paaudio *g = opaque;
    PAConnection *c = g->conn;

    if (--c->refcount == 0) {
        qpa_conn_fini(c);
    }

    g_free(g);
}

static struct audio_pcm_ops qpa_pcm_ops = {
    .init_out = qpa_init_out,
    .fini_out = qpa_fini_out,
    .run_out  = qpa_run_out,
    .write    = qpa_write,
    .ctl_out  = qpa_ctl_out,

    .init_in  = qpa_init_in,
    .fini_in  = qpa_fini_in,
    .run_in   = qpa_run_in,
    .read     = qpa_read,
    .ctl_in   = qpa_ctl_in
};

static struct audio_driver pa_audio_driver = {
    .name           = "pa",
    .descr          = "http://www.pulseaudio.org/",
    .init           = qpa_audio_init,
    .fini           = qpa_audio_fini,
    .pcm_ops        = &qpa_pcm_ops,
    .can_be_default = 1,
    .max_voices_out = INT_MAX,
    .max_voices_in  = INT_MAX,
    .voice_size_out = sizeof (PAVoiceOut),
    .voice_size_in  = sizeof (PAVoiceIn),
    .ctl_caps       = VOICE_VOLUME_CAP
};

static void register_audio_pa(void)
{
    audio_driver_register(&pa_audio_driver);
}
type_init(register_audio_pa);