src/audio/qsa/SDL_qsa_audio.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#include "SDL_config.h"

#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sched.h>
#include <sys/select.h>
#include <sys/neutrino.h>
#include <sys/asoundlib.h>

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "SDL_qsa_audio.h"

/* default channel communication parameters */
#define DEFAULT_CPARAMS_RATE   44100
#define DEFAULT_CPARAMS_VOICES 1

#define DEFAULT_CPARAMS_FRAG_SIZE 4096
#define DEFAULT_CPARAMS_FRAGS_MIN 1
#define DEFAULT_CPARAMS_FRAGS_MAX 1

#define QSA_NO_WORKAROUNDS  0x00000000
#define QSA_MMAP_WORKAROUND 0x00000001

struct BuggyCards
{
    char *cardname;
    unsigned long bugtype;
};

#define QSA_WA_CARDS             3
#define QSA_MAX_CARD_NAME_LENGTH 33

struct BuggyCards buggycards[QSA_WA_CARDS] = {
    {"Sound Blaster Live!", QSA_MMAP_WORKAROUND},
    {"Vortex 8820", QSA_MMAP_WORKAROUND},
    {"Vortex 8830", QSA_MMAP_WORKAROUND},
};

/* List of found devices */
#define QSA_MAX_DEVICES       32
#define QSA_MAX_NAME_LENGTH   81+16     /* Hardcoded in QSA, can't be changed */

typedef struct _QSA_Device
{
    char name[QSA_MAX_NAME_LENGTH];     /* Long audio device name for SDL  */
    int cardno;
    int deviceno;
} QSA_Device;

QSA_Device qsa_playback_device[QSA_MAX_DEVICES];
uint32_t qsa_playback_devices;

QSA_Device qsa_capture_device[QSA_MAX_DEVICES];
uint32_t qsa_capture_devices;

static inline void
QSA_SetError(const char *fn, int status)
{
    SDL_SetError("QSA: %s() failed: %s", fn, snd_strerror(status));
}

/* card names check to apply the workarounds */
static int
QSA_CheckBuggyCards(_THIS, unsigned long checkfor)
{
    char scardname[QSA_MAX_CARD_NAME_LENGTH];
    int it;

    if (snd_card_get_name
        (this->hidden->cardno, scardname, QSA_MAX_CARD_NAME_LENGTH - 1) < 0) {
        return 0;
    }

    for (it = 0; it < QSA_WA_CARDS; it++) {
        if (SDL_strcmp(buggycards[it].cardname, scardname) == 0) {
            if (buggycards[it].bugtype == checkfor) {
                return 1;
            }
        }
    }

    return 0;
}

/* !!! FIXME: does this need to be here? Does the SDL version not work? */
static void
QSA_ThreadInit(_THIS)
{
    struct sched_param param;
    int status;

    /* Increase default 10 priority to 25 to avoid jerky sound */
    status = SchedGet(0, 0, &param);
    param.sched_priority = param.sched_curpriority + 15;
    status = SchedSet(0, 0, SCHED_NOCHANGE, &param);
}

/* PCM channel parameters initialize function */
static void
QSA_InitAudioParams(snd_pcm_channel_params_t * cpars)
{
    SDL_memset(cpars, 0, sizeof(snd_pcm_channel_params_t));

    cpars->channel = SND_PCM_CHANNEL_PLAYBACK;
    cpars->mode = SND_PCM_MODE_BLOCK;
    cpars->start_mode = SND_PCM_START_DATA;
    cpars->stop_mode = SND_PCM_STOP_STOP;
    cpars->format.format = SND_PCM_SFMT_S16_LE;
    cpars->format.interleave = 1;
    cpars->format.rate = DEFAULT_CPARAMS_RATE;
    cpars->format.voices = DEFAULT_CPARAMS_VOICES;
    cpars->buf.block.frag_size = DEFAULT_CPARAMS_FRAG_SIZE;
    cpars->buf.block.frags_min = DEFAULT_CPARAMS_FRAGS_MIN;
    cpars->buf.block.frags_max = DEFAULT_CPARAMS_FRAGS_MAX;
}

/* This function waits until it is possible to write a full sound buffer */
static void
QSA_WaitDevice(_THIS)
{
    fd_set wfds;
    fd_set rfds;
    int selectret;
    struct timeval timeout;

    if (!this->hidden->iscapture) {
        FD_ZERO(&wfds);
        FD_SET(this->hidden->audio_fd, &wfds);
    } else {
        FD_ZERO(&rfds);
        FD_SET(this->hidden->audio_fd, &rfds);
    }

    do {
        /* Setup timeout for playing one fragment equal to 2 seconds          */
        /* If timeout occured than something wrong with hardware or driver    */
        /* For example, Vortex 8820 audio driver stucks on second DAC because */
        /* it doesn't exist !                                                 */
        timeout.tv_sec = 2;
        timeout.tv_usec = 0;
        this->hidden->timeout_on_wait = 0;

        if (!this->hidden->iscapture) {
            selectret =
                select(this->hidden->audio_fd + 1, NULL, &wfds, NULL,
                       &timeout);
        } else {
            selectret =
                select(this->hidden->audio_fd + 1, &rfds, NULL, NULL,
                       &timeout);
        }

        switch (selectret) {
        case -1:
            {
                SDL_SetError("QSA: select() failed: %s\n", strerror(errno));
                return;
            }
            break;
        case 0:
            {
                SDL_SetError("QSA: timeout on buffer waiting occured\n");
                this->hidden->timeout_on_wait = 1;
                return;
            }
            break;
        default:
            {
                if (!this->hidden->iscapture) {
                    if (FD_ISSET(this->hidden->audio_fd, &wfds)) {
                        return;
                    }
                } else {
                    if (FD_ISSET(this->hidden->audio_fd, &rfds)) {
                        return;
                    }
                }
            }
            break;
        }
    } while (1);
}

static void
QSA_PlayDevice(_THIS)
{
    snd_pcm_channel_status_t cstatus;
    int written;
    int status;
    int towrite;
    void *pcmbuffer;

    if ((!this->enabled) || (!this->hidden)) {
        return;
    }

    towrite = this->spec.size;
    pcmbuffer = this->hidden->pcm_buf;

    /* Write the audio data, checking for EAGAIN (buffer full) and underrun */
    do {
        written =
            snd_pcm_plugin_write(this->hidden->audio_handle, pcmbuffer,
                                 towrite);
        if (written != towrite) {
            /* Check if samples playback got stuck somewhere in hardware or in */
            /* the audio device driver */
            if ((errno == EAGAIN) && (written == 0)) {
                if (this->hidden->timeout_on_wait != 0) {
                    SDL_SetError("QSA: buffer playback timeout\n");
                    return;
                }
            }

            /* Check for errors or conditions */
            if ((errno == EAGAIN) || (errno == EWOULDBLOCK)) {
                /* Let a little CPU time go by and try to write again */
                SDL_Delay(1);

                /* if we wrote some data */
                towrite -= written;
                pcmbuffer += written * this->spec.channels;
                continue;
            } else {
                if ((errno == EINVAL) || (errno == EIO)) {
                    SDL_memset(&cstatus, 0, sizeof(cstatus));
                    if (!this->hidden->iscapture) {
                        cstatus.channel = SND_PCM_CHANNEL_PLAYBACK;
                    } else {
                        cstatus.channel = SND_PCM_CHANNEL_CAPTURE;
                    }

                    status =
                        snd_pcm_plugin_status(this->hidden->audio_handle,
                                              &cstatus);
                    if (status < 0) {
                        QSA_SetError("snd_pcm_plugin_status", status);
                        return;
                    }

                    if ((cstatus.status == SND_PCM_STATUS_UNDERRUN) ||
                        (cstatus.status == SND_PCM_STATUS_READY)) {
                        if (!this->hidden->iscapture) {
                            status =
                                snd_pcm_plugin_prepare(this->hidden->
                                                       audio_handle,
                                                       SND_PCM_CHANNEL_PLAYBACK);
                        } else {
                            status =
                                snd_pcm_plugin_prepare(this->hidden->
                                                       audio_handle,
                                                       SND_PCM_CHANNEL_CAPTURE);
                        }
                        if (status < 0) {
                            QSA_SetError("snd_pcm_plugin_prepare", status);
                            return;
                        }
                    }
                    continue;
                } else {
                    return;
                }
            }
        } else {
            /* we wrote all remaining data */
            towrite -= written;
            pcmbuffer += written * this->spec.channels;
        }
    } while ((towrite > 0) && (this->enabled));

    /* If we couldn't write, assume fatal error for now */
    if (towrite != 0) {
        this->enabled = 0;
    }
}

static Uint8 *
QSA_GetDeviceBuf(_THIS)
{
    return this->hidden->pcm_buf;
}

static void
QSA_CloseDevice(_THIS)
{
    if (this->hidden != NULL) {
        if (this->hidden->audio_handle != NULL) {
            if (!this->hidden->iscapture) {
                /* Finish playing available samples */
                snd_pcm_plugin_flush(this->hidden->audio_handle,
                                     SND_PCM_CHANNEL_PLAYBACK);
            } else {
                /* Cancel unread samples during capture */
                snd_pcm_plugin_flush(this->hidden->audio_handle,
                                     SND_PCM_CHANNEL_CAPTURE);
            }
            snd_pcm_close(this->hidden->audio_handle);
            this->hidden->audio_handle = NULL;
        }

        if (this->hidden->pcm_buf != NULL) {
            SDL_FreeAudioMem(this->hidden->pcm_buf);
            this->hidden->pcm_buf = NULL;
        }

        SDL_free(this->hidden);
        this->hidden = NULL;
    }
}

static int
QSA_OpenDevice(_THIS, const char *devname, int iscapture)
{
    int status = 0;
    int format = 0;
    SDL_AudioFormat test_format = 0;
    int found = 0;
    snd_pcm_channel_setup_t csetup;
    snd_pcm_channel_params_t cparams;

    /* Initialize all variables that we clean on shutdown */
    this->hidden =
        (struct SDL_PrivateAudioData *) SDL_calloc(1,
                                                   (sizeof
                                                    (struct
                                                     SDL_PrivateAudioData)));
    if (this->hidden == NULL) {
        SDL_OutOfMemory();
        return 0;
    }
    SDL_memset(this->hidden, 0, sizeof(struct SDL_PrivateAudioData));

    /* Initialize channel transfer parameters to default */
    QSA_InitAudioParams(&cparams);

    /* Initialize channel direction: capture or playback */
    this->hidden->iscapture = iscapture;

    /* Find deviceid and cardid by device name for playback */
    if ((!this->hidden->iscapture) && (devname != NULL)) {
        uint32_t device;
        int32_t status;

        /* Search in the playback devices */
        device = 0;
        do {
            status = SDL_strcmp(qsa_playback_device[device].name, devname);
            if (status == 0) {
                /* Found requested device */
                this->hidden->deviceno = qsa_playback_device[device].deviceno;
                this->hidden->cardno = qsa_playback_device[device].cardno;
                break;
            }
            device++;
            if (device >= qsa_playback_devices) {
                QSA_CloseDevice(this);
                SDL_SetError("No such playback device");
                return 0;
            }
        } while (1);
    }

    /* Find deviceid and cardid by device name for capture */
    if ((this->hidden->iscapture) && (devname != NULL)) {
        /* Search in the capture devices */
        uint32_t device;
        int32_t status;

        /* Searching in the playback devices */
        device = 0;
        do {
            status = SDL_strcmp(qsa_capture_device[device].name, devname);
            if (status == 0) {
                /* Found requested device */
                this->hidden->deviceno = qsa_capture_device[device].deviceno;
                this->hidden->cardno = qsa_capture_device[device].cardno;
                break;
            }
            device++;
            if (device >= qsa_capture_devices) {
                QSA_CloseDevice(this);
                SDL_SetError("No such capture device");
                return 0;
            }
        } while (1);
    }

    /* Check if SDL requested default audio device */
    if (devname == NULL) {
        /* Open system default audio device */
        if (!this->hidden->iscapture) {
            status = snd_pcm_open_preferred(&this->hidden->audio_handle,
                                            &this->hidden->cardno,
                                            &this->hidden->deviceno,
                                            SND_PCM_OPEN_PLAYBACK);
        } else {
            status = snd_pcm_open_preferred(&this->hidden->audio_handle,
                                            &this->hidden->cardno,
                                            &this->hidden->deviceno,
                                            SND_PCM_OPEN_CAPTURE);
        }
    } else {
        /* Open requested audio device */
        if (!this->hidden->iscapture) {
            status =
                snd_pcm_open(&this->hidden->audio_handle,
                             this->hidden->cardno, this->hidden->deviceno,
                             SND_PCM_OPEN_PLAYBACK);
        } else {
            status =
                snd_pcm_open(&this->hidden->audio_handle,
                             this->hidden->cardno, this->hidden->deviceno,
                             SND_PCM_OPEN_CAPTURE);
        }
    }

    /* Check if requested device is opened */
    if (status < 0) {
        this->hidden->audio_handle = NULL;
        QSA_CloseDevice(this);
        QSA_SetError("snd_pcm_open", status);
        return 0;
    }

    if (!QSA_CheckBuggyCards(this, QSA_MMAP_WORKAROUND)) {
        /* Disable QSA MMAP plugin for buggy audio drivers */
        status =
            snd_pcm_plugin_set_disable(this->hidden->audio_handle,
                                       PLUGIN_DISABLE_MMAP);
        if (status < 0) {
            QSA_CloseDevice(this);
            QSA_SetError("snd_pcm_plugin_set_disable", status);
            return 0;
        }
    }

    /* Try for a closest match on audio format */
    format = 0;
    /* can't use format as SND_PCM_SFMT_U8 = 0 in qsa */
    found = 0;

    for (test_format = SDL_FirstAudioFormat(this->spec.format); !found;) {
        /* if match found set format to equivalent QSA format */
        switch (test_format) {
        case AUDIO_U8:
            {
                format = SND_PCM_SFMT_U8;
                found = 1;
            }
            break;
        case AUDIO_S8:
            {
                format = SND_PCM_SFMT_S8;
                found = 1;
            }
            break;
        case AUDIO_S16LSB:
            {
                format = SND_PCM_SFMT_S16_LE;
                found = 1;
            }
            break;
        case AUDIO_S16MSB:
            {
                format = SND_PCM_SFMT_S16_BE;
                found = 1;
            }
            break;
        case AUDIO_U16LSB:
            {
                format = SND_PCM_SFMT_U16_LE;
                found = 1;
            }
            break;
        case AUDIO_U16MSB:
            {
                format = SND_PCM_SFMT_U16_BE;
                found = 1;
            }
            break;
        case AUDIO_S32LSB:
            {
                format = SND_PCM_SFMT_S32_LE;
                found = 1;
            }
            break;
        case AUDIO_S32MSB:
            {
                format = SND_PCM_SFMT_S32_BE;
                found = 1;
            }
            break;
        case AUDIO_F32LSB:
            {
                format = SND_PCM_SFMT_FLOAT_LE;
                found = 1;
            }
            break;
        case AUDIO_F32MSB:
            {
                format = SND_PCM_SFMT_FLOAT_BE;
                found = 1;
            }
            break;
        default:
            {
                break;
            }
        }

        if (!found) {
            test_format = SDL_NextAudioFormat();
        }
    }

    /* assumes test_format not 0 on success */
    if (test_format == 0) {
        QSA_CloseDevice(this);
        SDL_SetError("QSA: Couldn't find any hardware audio formats");
        return 0;
    }

    this->spec.format = test_format;

    /* Set the audio format */
    cparams.format.format = format;

    /* Set mono/stereo/4ch/6ch/8ch audio */
    cparams.format.voices = this->spec.channels;

    /* Set rate */
    cparams.format.rate = this->spec.freq;

    /* Setup the transfer parameters according to cparams */
    status = snd_pcm_plugin_params(this->hidden->audio_handle, &cparams);
    if (status < 0) {
        QSA_CloseDevice(this);
        QSA_SetError("snd_pcm_channel_params", status);
        return 0;
    }

    /* Make sure channel is setup right one last time */
    SDL_memset(&csetup, '\0', sizeof(csetup));
    if (!this->hidden->iscapture) {
        csetup.channel = SND_PCM_CHANNEL_PLAYBACK;
    } else {
        csetup.channel = SND_PCM_CHANNEL_CAPTURE;
    }

    /* Setup an audio channel */
    if (snd_pcm_plugin_setup(this->hidden->audio_handle, &csetup) < 0) {
        QSA_CloseDevice(this);
        SDL_SetError("QSA: Unable to setup channel\n");
        return 0;
    }

    /* Calculate the final parameters for this audio specification */
    SDL_CalculateAudioSpec(&this->spec);

    this->hidden->pcm_len = this->spec.size;

    if (this->hidden->pcm_len == 0) {
        this->hidden->pcm_len =
            csetup.buf.block.frag_size * this->spec.channels *
            (snd_pcm_format_width(format) / 8);
    }

    /*
     * Allocate memory to the audio buffer and initialize with silence
     *  (Note that buffer size must be a multiple of fragment size, so find
     *  closest multiple)
     */
    this->hidden->pcm_buf =
        (Uint8 *) SDL_AllocAudioMem(this->hidden->pcm_len);
    if (this->hidden->pcm_buf == NULL) {
        QSA_CloseDevice(this);
        SDL_OutOfMemory();
        return 0;
    }
    SDL_memset(this->hidden->pcm_buf, this->spec.silence,
               this->hidden->pcm_len);

    /* get the file descriptor */
    if (!this->hidden->iscapture) {
        this->hidden->audio_fd =
            snd_pcm_file_descriptor(this->hidden->audio_handle,
                                    SND_PCM_CHANNEL_PLAYBACK);
    } else {
        this->hidden->audio_fd =
            snd_pcm_file_descriptor(this->hidden->audio_handle,
                                    SND_PCM_CHANNEL_CAPTURE);
    }

    if (this->hidden->audio_fd < 0) {
        QSA_CloseDevice(this);
        QSA_SetError("snd_pcm_file_descriptor", status);
        return 0;
    }

    /* Prepare an audio channel */
    if (!this->hidden->iscapture) {
        /* Prepare audio playback */
        status =
            snd_pcm_plugin_prepare(this->hidden->audio_handle,
                                   SND_PCM_CHANNEL_PLAYBACK);
    } else {
        /* Prepare audio capture */
        status =
            snd_pcm_plugin_prepare(this->hidden->audio_handle,
                                   SND_PCM_CHANNEL_CAPTURE);
    }

    if (status < 0) {
        QSA_CloseDevice(this);
        QSA_SetError("snd_pcm_plugin_prepare", status);
        return 0;
    }

    /* We're really ready to rock and roll. :-) */
    return 1;
}

static void
QSA_DetectDevices(int iscapture, SDL_AddAudioDevice addfn)
{
    uint32_t it;
    uint32_t cards;
    uint32_t devices;
    int32_t status;

    /* Detect amount of available devices       */
    /* this value can be changed in the runtime */
    cards = snd_cards();

    /* If io-audio manager is not running we will get 0 as number */
    /* of available audio devices                                 */
    if (cards == 0) {
        /* We have no any available audio devices */
        return;
    }

    /* Find requested devices by type */
    if (!iscapture) {
        /* Playback devices enumeration requested */
        for (it = 0; it < cards; it++) {
            devices = 0;
            do {
                status =
                    snd_card_get_longname(it,
                                          qsa_playback_device
                                          [qsa_playback_devices].name,
                                          QSA_MAX_NAME_LENGTH);
                if (status == EOK) {
                    snd_pcm_t *handle;

                    /* Add device number to device name */
                    sprintf(qsa_playback_device[qsa_playback_devices].name +
                            SDL_strlen(qsa_playback_device
                                       [qsa_playback_devices].name), " d%d",
                            devices);

                    /* Store associated card number id */
                    qsa_playback_device[qsa_playback_devices].cardno = it;

                    /* Check if this device id could play anything */
                    status =
                        snd_pcm_open(&handle, it, devices,
                                     SND_PCM_OPEN_PLAYBACK);
                    if (status == EOK) {
                        qsa_playback_device[qsa_playback_devices].deviceno =
                            devices;
                        status = snd_pcm_close(handle);
                        if (status == EOK) {
                            addfn(qsa_playback_device[qsa_playback_devices].name);
                            qsa_playback_devices++;
                        }
                    } else {
                        /* Check if we got end of devices list */
                        if (status == -ENOENT) {
                            break;
                        }
                    }
                } else {
                    break;
                }

                /* Check if we reached maximum devices count */
                if (qsa_playback_devices >= QSA_MAX_DEVICES) {
                    break;
                }
                devices++;
            } while (1);

            /* Check if we reached maximum devices count */
            if (qsa_playback_devices >= QSA_MAX_DEVICES) {
                break;
            }
        }
    } else {
        /* Capture devices enumeration requested */
        for (it = 0; it < cards; it++) {
            devices = 0;
            do {
                status =
                    snd_card_get_longname(it,
                                          qsa_capture_device
                                          [qsa_capture_devices].name,
                                          QSA_MAX_NAME_LENGTH);
                if (status == EOK) {
                    snd_pcm_t *handle;

                    /* Add device number to device name */
                    sprintf(qsa_capture_device[qsa_capture_devices].name +
                            SDL_strlen(qsa_capture_device
                                       [qsa_capture_devices].name), " d%d",
                            devices);

                    /* Store associated card number id */
                    qsa_capture_device[qsa_capture_devices].cardno = it;

                    /* Check if this device id could play anything */
                    status =
                        snd_pcm_open(&handle, it, devices,
                                     SND_PCM_OPEN_CAPTURE);
                    if (status == EOK) {
                        qsa_capture_device[qsa_capture_devices].deviceno =
                            devices;
                        status = snd_pcm_close(handle);
                        if (status == EOK) {
                            addfn(qsa_capture_device[qsa_capture_devices].name);
                            qsa_capture_devices++;
                        }
                    } else {
                        /* Check if we got end of devices list */
                        if (status == -ENOENT) {
                            break;
                        }
                    }

                    /* Check if we reached maximum devices count */
                    if (qsa_capture_devices >= QSA_MAX_DEVICES) {
                        break;
                    }
                } else {
                    break;
                }
                devices++;
            } while (1);

            /* Check if we reached maximum devices count */
            if (qsa_capture_devices >= QSA_MAX_DEVICES) {
                break;
            }
        }
    }
}

static void
QSA_WaitDone(_THIS)
{
    if (!this->hidden->iscapture) {
        if (this->hidden->audio_handle != NULL) {
            /* Wait till last fragment is played and stop channel */
            snd_pcm_plugin_flush(this->hidden->audio_handle,
                                 SND_PCM_CHANNEL_PLAYBACK);
        }
    } else {
        if (this->hidden->audio_handle != NULL) {
            /* Discard all unread data and stop channel */
            snd_pcm_plugin_flush(this->hidden->audio_handle,
                                 SND_PCM_CHANNEL_CAPTURE);
        }
    }
}

static void
QSA_Deinitialize(void)
{
    /* Clear devices array on shutdown */
    SDL_memset(qsa_playback_device, 0x00,
               sizeof(QSA_Device) * QSA_MAX_DEVICES);
    SDL_memset(qsa_capture_device, 0x00,
               sizeof(QSA_Device) * QSA_MAX_DEVICES);
    qsa_playback_devices = 0;
    qsa_capture_devices = 0;
}

static int
QSA_Init(SDL_AudioDriverImpl * impl)
{
    snd_pcm_t *handle = NULL;
    int32_t status = 0;

    /* Clear devices array */
    SDL_memset(qsa_playback_device, 0x00,
               sizeof(QSA_Device) * QSA_MAX_DEVICES);
    SDL_memset(qsa_capture_device, 0x00,
               sizeof(QSA_Device) * QSA_MAX_DEVICES);
    qsa_playback_devices = 0;
    qsa_capture_devices = 0;

    /* Set function pointers                                     */
    /* DeviceLock and DeviceUnlock functions are used default,   */
    /* provided by SDL, which uses pthread_mutex for lock/unlock */
    impl->DetectDevices = QSA_DetectDevices;
    impl->OpenDevice = QSA_OpenDevice;
    impl->ThreadInit = QSA_ThreadInit;
    impl->WaitDevice = QSA_WaitDevice;
    impl->PlayDevice = QSA_PlayDevice;
    impl->GetDeviceBuf = QSA_GetDeviceBuf;
    impl->CloseDevice = QSA_CloseDevice;
    impl->WaitDone = QSA_WaitDone;
    impl->Deinitialize = QSA_Deinitialize;
    impl->LockDevice = NULL;
    impl->UnlockDevice = NULL;

    impl->OnlyHasDefaultOutputDevice = 0;
    impl->ProvidesOwnCallbackThread = 0;
    impl->SkipMixerLock = 0;
    impl->HasCaptureSupport = 1;
    impl->OnlyHasDefaultOutputDevice = 0;
    impl->OnlyHasDefaultInputDevice = 0;

    /* Check if io-audio manager is running or not */
    status = snd_cards();
    if (status == 0) {
        /* if no, return immediately */
        return 1;
    }

    return 1;   /* this audio target is available. */
}

AudioBootStrap QSAAUDIO_bootstrap = {
    "qsa", "QNX QSA Audio", QSA_Init, 0
};

/* vi: set ts=4 sw=4 expandtab: */