/*
- * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
snd_pcm_t *handle;
/** Determined and set by alsa_init(). */
int bytes_per_frame;
- /**
- * The sample rate given by command line option or the decoder
- * of the writer node group.
+ /*
+ * If the sample rate is not given at the command line and no wav
+ * header was detected, the btr exec mechanism is employed to query the
+ * ancestor buffer tree nodes for this information. In a typical setup
+ * the decoder passes the sample rate back to the alsa writer.
+ *
+ * \sa \ref btr_exec_up().
*/
unsigned sample_rate;
- snd_pcm_format_t sample_format;
- /**
- * The number of channels, given by command line option or the
- * decoder of the writer node group.
+ /*
+ * The sample format (8/16 bit, signed/unsigned, little/big endian) is
+ * determined in the same way as the \a sample_rate.
*/
+ snd_pcm_format_t sample_format;
+ /* The number of channels, again determined like \a sample_rate. */
unsigned channels;
+ /* time until buffer underrun occurs, in milliseconds */
+ unsigned buffer_time;
struct timeval drain_barrier;
/* File descriptor for select(). */
int poll_fd;
static int alsa_init(struct private_alsa_write_data *pad,
struct alsa_write_args_info *conf)
{
- snd_pcm_hw_params_t *hwparams;
- snd_pcm_sw_params_t *swparams;
+ snd_pcm_hw_params_t *hwparams = NULL;
+ snd_pcm_sw_params_t *swparams = NULL;
snd_pcm_uframes_t start_threshold, stop_threshold;
snd_pcm_uframes_t buffer_size, period_size;
snd_output_t *output_log;
- unsigned buffer_time;
int ret;
const char *msg;
+ unsigned period_time;
PARA_INFO_LOG("opening %s\n", conf->device_arg);
msg = "unable to open pcm";
SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if (ret < 0)
goto fail;
- snd_pcm_hw_params_alloca(&hwparams);
+ ret = snd_pcm_hw_params_malloc(&hwparams);
+ assert(ret >= 0);
msg = "Broken alsa configuration";
ret = snd_pcm_hw_params_any(pad->handle, hwparams);
if (ret < 0)
&pad->sample_rate, NULL);
if (ret < 0)
goto fail;
- msg = "unable to get buffer time";
- ret = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time,
- NULL);
- if (ret < 0 || buffer_time == 0)
- goto fail;
- /* buffer at most 500 milliseconds */
- buffer_time = PARA_MIN(buffer_time, 500U * 1000U);
+ /* alsa wants microseconds */
+ pad->buffer_time = conf->buffer_time_arg * 1000;
msg = "could not set buffer time";
ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
- &buffer_time, NULL);
+ &pad->buffer_time, NULL);
if (ret < 0)
goto fail;
+ pad->buffer_time /= 1000; /* we prefer milliseconds */
+ period_time = pad->buffer_time * 250; /* buffer time / 4 */
+ msg = "could not set period time";
+ ret = snd_pcm_hw_params_set_period_time_near(pad->handle, hwparams,
+ &period_time, NULL);
+ if (ret < 0)
+ goto fail;
+
msg = "unable to install hw params";
ret = snd_pcm_hw_params(pad->handle, hwparams);
if (ret < 0)
goto fail;
/* software parameter setup */
- snd_pcm_sw_params_alloca(&swparams);
+ ret = snd_pcm_sw_params_malloc(&swparams);
+ assert(ret >= 0);
snd_pcm_sw_params_current(pad->handle, swparams);
snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
if (buffer_size < 1)
goto fail;
ret = snd_output_buffer_open(&output_log);
if (ret == 0) {
- char *buf;
- PARA_INFO_LOG("dumping alsa configuration\n");
+ char *buf, *p;
+ size_t sz;
+ PARA_DEBUG_LOG("dumping alsa configuration\n");
snd_pcm_dump(pad->handle, output_log);
- snd_output_buffer_string(output_log, &buf);
- for (;;) {
- char *p = strchr(buf, '\n');
- if (!p) /* omit last output line, it's empty */
+ snd_pcm_hw_params_dump(hwparams, output_log);
+ sz = snd_output_buffer_string(output_log, &buf);
+ for (p = buf; p < buf + sz;) {
+ char *q = memchr(p, '\n', buf + sz - p);
+ if (!q)
break;
- *p = '\0';
- PARA_INFO_LOG("%s\n", buf);
- buf = p + 1;
+ *q = '\0';
+ PARA_DEBUG_LOG("%s\n", p);
+ p = q + 1;
}
snd_output_close(output_log);
}
- return 1;
+ ret = 1;
+ goto out;
fail:
if (ret < 0)
PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
else
PARA_ERROR_LOG("%s\n", msg);
- return -E_ALSA;
+ ret = -E_ALSA;
+out:
+ snd_pcm_hw_params_free(hwparams);
+ snd_pcm_sw_params_free(swparams);
+ return ret;
}
-static void alsa_write_pre_select(struct sched *s, struct task *t)
+static void alsa_write_pre_select(struct sched *s, void *context)
{
struct pollfd pfd;
- struct writer_node *wn = container_of(t, struct writer_node, task);
+ struct writer_node *wn = context;
struct private_alsa_write_data *pad = wn->private_data;
int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
return;
}
+ /* wait at most 50% of the buffer time */
+ sched_request_timeout_ms(pad->buffer_time / 2, s);
ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
if (ret < 0) {
PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
snd_strerror(-ret));
- t->error = -E_ALSA;
return;
}
pad->poll_fd = pfd.fd;
free(pad);
}
-static int alsa_write_post_select(__a_unused struct sched *s,
- struct task *t)
+static int alsa_write_post_select(__a_unused struct sched *s, void *context)
{
- struct writer_node *wn = container_of(t, struct writer_node, task);
+ struct writer_node *wn = context;
struct private_alsa_write_data *pad = wn->private_data;
struct btr_node *btrn = wn->btrn;
char *data;
snd_pcm_sframes_t frames;
int ret;
- ret = task_get_notification(t);
+ ret = task_get_notification(wn->task);
if (ret < 0)
goto err;
again:
wn->min_iqs = pad->bytes_per_frame;
goto again;
}
- if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
- return 0;
frames = bytes / pad->bytes_per_frame;
frames = snd_pcm_writei(pad->handle, data, frames);
if (frames == 0 || frames == -EAGAIN) {
- /*
- * The alsa poll fd was ready for IO but we failed to write to
- * the alsa handle. This means another event is pending. We
- * don't care about that but we have to dispatch the event in
- * order to avoid a busy loop. So we simply read from the poll
- * fd.
- */
char buf[100];
- if (read(pad->poll_fd, buf, 100))
- do_nothing;
+ if (pad->poll_fd >= 0 && FD_ISSET(pad->poll_fd, &s->rfds))
+ if (read(pad->poll_fd, buf, 100))
+ do_nothing;
return 0;
}
if (frames > 0) {
w->post_select = alsa_write_post_select;
w->parse_config_or_die = alsa_parse_config_or_die;
w->free_config = alsa_free_config;
- w->help = (struct ggo_help) {
- .short_help = alsa_write_args_info_help,
- .detailed_help = alsa_write_args_info_detailed_help
- };
+ w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
alsa_write_cmdline_parser_free(&dummy);
}
projects / paraslash.git / blobdiff