/*
- * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
#include <regex.h>
#include <sys/types.h>
#include <alsa/asoundlib.h>
-#include <sys/time.h>
-#include <stdbool.h>
#include "para.h"
#include "fd.h"
snd_pcm_t *handle;
/** Determined and set by alsa_init(). */
int bytes_per_frame;
- /** The approximate maximum buffer duration in us. */
- unsigned buffer_time;
- /* Number of frames that fit into the buffer. */
- snd_pcm_uframes_t buffer_frames;
- /**
- * 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 period_size;
- int err;
+ snd_pcm_uframes_t buffer_size, period_size;
+ snd_output_t *output_log;
+ int ret;
+ const char *msg;
+ unsigned period_time;
PARA_INFO_LOG("opening %s\n", conf->device_arg);
- err = snd_pcm_open(&pad->handle, conf->device_arg,
+ msg = "unable to open pcm";
+ ret = snd_pcm_open(&pad->handle, conf->device_arg,
SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
- if (err < 0)
- return -E_PCM_OPEN;
-
- snd_pcm_hw_params_alloca(&hwparams);
- snd_pcm_sw_params_alloca(&swparams);
- if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
- return -E_BROKEN_CONF;
- if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
- SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
- return -E_ACCESS_TYPE;
- if (snd_pcm_hw_params_set_format(pad->handle, hwparams,
- pad->sample_format) < 0)
- return -E_SAMPLE_FORMAT;
- if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
- pad->channels) < 0)
- return -E_CHANNEL_COUNT;
- if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
- &pad->sample_rate, NULL) < 0)
- return -E_SET_RATE;
- err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
+ if (ret < 0)
+ goto fail;
+ 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)
+ goto fail;
+ msg = "access type not available";
+ ret = snd_pcm_hw_params_set_access(pad->handle, hwparams,
+ SND_PCM_ACCESS_RW_INTERLEAVED);
+ if (ret < 0)
+ goto fail;
+ msg = "sample format not available";
+ ret = snd_pcm_hw_params_set_format(pad->handle, hwparams,
+ pad->sample_format);
+ if (ret < 0)
+ goto fail;
+ msg = "channels count not available";
+ ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams,
+ pad->channels);
+ if (ret < 0)
+ goto fail;
+ msg = "could not set sample rate";
+ ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
+ &pad->sample_rate, NULL);
+ if (ret < 0)
+ goto fail;
+ /* 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,
&pad->buffer_time, NULL);
- if (err < 0 || !pad->buffer_time)
- return -E_GET_BUFFER_TIME;
- PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
- if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
- &pad->buffer_time, NULL) < 0)
- return -E_SET_BUFFER_TIME;
- if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
- return -E_HW_PARAMS;
+ 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;
snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
- snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
- PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames,
- period_size);
- if (period_size == pad->buffer_frames)
- return -E_BAD_PERIOD;
+ snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
+ msg = "period size equals buffer size";
+ if (period_size == buffer_size)
+ goto fail;
+
+ /* software parameter setup */
+ 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 (pad->buffer_frames < 1)
+ if (buffer_size < 1)
start_threshold = 1;
else
- start_threshold = PARA_MIN(pad->buffer_frames,
+ start_threshold = PARA_MIN(buffer_size,
(snd_pcm_uframes_t)pad->sample_rate);
- if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
- start_threshold) < 0)
- return -E_START_THRESHOLD;
- stop_threshold = pad->buffer_frames;
- if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
- stop_threshold) < 0)
- return -E_STOP_THRESHOLD;
- if (snd_pcm_sw_params(pad->handle, swparams) < 0)
- PARA_WARNING_LOG("unable to install sw params\n");
- pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format)
- * pad->channels / 8;
- if (pad->bytes_per_frame <= 0)
- return -E_PHYSICAL_WIDTH;
- PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
- if (snd_pcm_nonblock(pad->handle, 1))
- PARA_ERROR_LOG("failed to set nonblock mode\n");
- return 1;
+ msg = "could not set start threshold";
+ ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
+ start_threshold);
+ if (ret < 0)
+ goto fail;
+ stop_threshold = buffer_size;
+ msg = "could not set stop threshold";
+ ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
+ stop_threshold);
+ if (ret < 0)
+ goto fail;
+ msg = "unable to install sw params";
+ ret = snd_pcm_sw_params(pad->handle, swparams);
+ if (ret < 0)
+ goto fail;
+ msg = "unable to determine bytes per frame";
+ ret = snd_pcm_format_physical_width(pad->sample_format);
+ if (ret <= 0)
+ goto fail;
+ pad->bytes_per_frame = ret * pad->channels / 8;
+ msg = "failed to set alsa handle to nonblock mode";
+ ret = snd_pcm_nonblock(pad->handle, 1);
+ if (ret < 0)
+ goto fail;
+ ret = snd_output_buffer_open(&output_log);
+ if (ret == 0) {
+ char *buf, *p;
+ size_t sz;
+ PARA_DEBUG_LOG("dumping alsa configuration\n");
+ snd_pcm_dump(pad->handle, output_log);
+ 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;
+ *q = '\0';
+ PARA_DEBUG_LOG("%s\n", p);
+ p = q + 1;
+ }
+ snd_output_close(output_log);
+ }
+ 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);
+ 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("%s\n", snd_strerror(-ret));
- t->error = -E_ALSA_POLL_FDS;
+ PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
+ snd_strerror(-ret));
return;
}
pad->poll_fd = pfd.fd;
free(pad);
}
-static void 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(wn->task);
+ if (ret < 0)
+ goto err;
again:
- t->error = 0;
ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
if (ret == 0)
- return;
+ return 0;
btr_merge(btrn, wn->min_iqs);
bytes = btr_next_buffer(btrn, &data);
if (ret < 0 || bytes < wn->min_iqs) { /* eof */
PARA_DEBUG_LOG("waiting for device to drain\n");
tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
&pad->drain_barrier);
- return;
+ return 0;
}
if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
goto err;
- return;
+ return 0;
}
if (!pad) {
int32_t val;
if (bytes == 0) /* no data available */
- return;
+ return 0;
pad = para_calloc(sizeof(*pad));
get_btr_sample_rate(btrn, &val);
pad->sample_rate = val;
wn->min_iqs = pad->bytes_per_frame;
goto again;
}
- if (pad->poll_fd >= 0 && !FD_ISSET(pad->poll_fd, &s->rfds))
- return;
frames = bytes / pad->bytes_per_frame;
frames = snd_pcm_writei(pad->handle, data, frames);
- if (frames == 0 || frames == -EAGAIN)
- return;
+ if (frames == 0 || frames == -EAGAIN) {
+ char buf[100];
+ 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) {
btr_consume(btrn, frames * pad->bytes_per_frame);
goto again;
if (frames == -EPIPE) {
PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
snd_pcm_prepare(pad->handle);
- return;
+ return 0;
}
- PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
- ret = -E_ALSA_WRITE;
+ PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
+ ret = -E_ALSA;
err:
assert(ret < 0);
- btr_remove_node(btrn);
- t->error = ret;
+ btr_remove_node(&wn->btrn);
+ return ret;
}
-__malloc static void *alsa_parse_config_or_die(const char *options)
+__malloc static void *alsa_parse_config_or_die(int argc, char **argv)
{
struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
/* exits on errors */
- alsa_cmdline_parser_string(options, conf, "alsa_write");
+ alsa_write_cmdline_parser(argc, argv, conf);
return conf;
}
static void alsa_free_config(void *conf)
{
- alsa_cmdline_parser_free(conf);
+ alsa_write_cmdline_parser_free(conf);
}
/**
{
struct alsa_write_args_info dummy;
- alsa_cmdline_parser_init(&dummy);
+ alsa_write_cmdline_parser_init(&dummy);
w->close = alsa_close;
w->pre_select = alsa_write_pre_select;
w->post_select = alsa_write_post_select;
w->parse_config_or_die = alsa_parse_config_or_die;
- w->shutdown = NULL; /* nothing to do */
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
- };
- alsa_cmdline_parser_free(&dummy);
+ w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
+ alsa_write_cmdline_parser_free(&dummy);
}
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