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jack: lockless data transfer to jack thread 

The JACK documentation postulates that the process() callback must not
block, therefore locking is forbidden.  Anyway, the old code was racy.

Remove all locks, and don't wait for more data to become available -
just send to the port what is already in the buffer.
This commit is contained in:
Max Kellermann 2008-10-24 16:55:51 +02:00
parent 4ecdaabbb0
commit 0a6704420b
1 changed files with 15 additions and 47 deletions
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62
src/audioOutputs/audioOutput_jack.c
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@ -41,10 +41,6 @@ typedef struct _JackData {
/* for srate() only */
struct audio_format *audio_format;
/* locks */
pthread_mutex_t play_audio_lock;
pthread_cond_t play_audio;
/* jack library stuff */
jack_port_t *ports[2];
jack_client_t *client;
@ -64,9 +60,6 @@ static JackData *newJackData(void)
ret->name = "mpd";
ret->ringbuf_sz = 32768;
pthread_mutex_init(&ret->play_audio_lock, NULL);
pthread_cond_init(&ret->play_audio, NULL);
return ret;
}
@ -89,9 +82,6 @@ static void freeJackClient(JackData *jd)
jack_ringbuffer_free(jd->ringbuffer[1]);
jd->ringbuffer[1] = NULL;
}
pthread_mutex_destroy(&jd->play_audio_lock);
pthread_cond_destroy(&jd->play_audio);
}
static void freeJackData(JackData *jd)
@ -133,50 +123,29 @@ static int srate(mpd_unused jack_nframes_t rate, void *data)
static int process(jack_nframes_t nframes, void *arg)
{
size_t i;
JackData *jd = (JackData *) arg;
jack_default_audio_sample_t *out[2];
jack_default_audio_sample_t *out;
size_t avail_data, avail_frames;
if (nframes <= 0)
return 0;
out[0] = jack_port_get_buffer(jd->ports[0], nframes);
out[1] = jack_port_get_buffer(jd->ports[1], nframes);
for (unsigned i = 0; i < 2; ++i) {
avail_data = jack_ringbuffer_read_space(jd->ringbuffer[i]);
if (avail_data > nframes * sample_size)
avail_data = nframes * sample_size;
while (nframes) {
avail_data = jack_ringbuffer_read_space(jd->ringbuffer[1]);
avail_frames = avail_data / sample_size;
if ( avail_data > 0 ) {
avail_frames = avail_data / sample_size;
out = jack_port_get_buffer(jd->ports[i], nframes);
jack_ringbuffer_read(jd->ringbuffer[i],
(char *)out, avail_data);
if (avail_frames > nframes) {
avail_frames = nframes;
avail_data = nframes*sample_size;
}
jack_ringbuffer_read(jd->ringbuffer[0], (char *)out[0],
avail_data);
jack_ringbuffer_read(jd->ringbuffer[1], (char *)out[1],
avail_data);
nframes -= avail_frames;
out[0] += avail_data;
out[1] += avail_data;
} else {
for (i = 0; i < nframes; i++)
out[0][i] = out[1][i] = 0.0;
nframes = 0;
}
if (pthread_mutex_trylock (&jd->play_audio_lock) == 0) {
pthread_cond_signal (&jd->play_audio);
pthread_mutex_unlock (&jd->play_audio_lock);
}
while (avail_frames < nframes)
/* ringbuffer underrun, fill with silence */
out[avail_frames++] = 0.0;
}
/*DEBUG("process (pid=%d)\n", getpid());*/
return 0;
}
@ -426,10 +395,9 @@ static int jack_playAudio(void *data,
sample_size);
}
} else {
pthread_mutex_lock(&jd->play_audio_lock);
pthread_cond_wait(&jd->play_audio,
&jd->play_audio_lock);
pthread_mutex_unlock(&jd->play_audio_lock);
/* XXX do something more intelligent to
synchronize */
my_usleep(10000);
}
}