2 * Copyright (C) 2005-2012 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file alsa_write.c paraslash's alsa output plugin */
10 * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
11 * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
12 * based on the vplay program by Michael Beck.
16 #include <sys/types.h>
17 #include <alsa/asoundlib.h>
26 #include "buffer_tree.h"
28 #include "write_common.h"
29 #include "alsa_write.cmdline.h"
32 /** Data specific to the alsa writer. */
33 struct private_alsa_write_data {
34 /** The alsa handle */
36 /** Determined and set by alsa_init(). */
39 * The sample rate given by command line option or the decoder
40 * of the writer node group.
43 snd_pcm_format_t sample_format;
45 * The number of channels, given by command line option or the
46 * decoder of the writer node group.
49 struct timeval drain_barrier;
50 /* File descriptor for select(). */
54 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
57 case SF_S8: return SND_PCM_FORMAT_S8;
58 case SF_U8: return SND_PCM_FORMAT_U8;
59 case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
60 case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
61 case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
62 case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
63 default: return SND_PCM_FORMAT_S16_LE;
67 /* Install PCM software and hardware configuration. */
68 static int alsa_init(struct private_alsa_write_data *pad,
69 struct alsa_write_args_info *conf)
71 snd_pcm_hw_params_t *hwparams;
72 snd_pcm_sw_params_t *swparams;
73 snd_pcm_uframes_t start_threshold, stop_threshold;
74 snd_pcm_uframes_t buffer_size, period_size;
75 snd_output_t *output_log;
80 PARA_INFO_LOG("opening %s\n", conf->device_arg);
81 msg = "unable to open pcm";
82 ret = snd_pcm_open(&pad->handle, conf->device_arg,
83 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
86 snd_pcm_hw_params_alloca(&hwparams);
87 msg = "Broken alsa configuration";
88 ret = snd_pcm_hw_params_any(pad->handle, hwparams);
91 msg = "access type not available";
92 ret = snd_pcm_hw_params_set_access(pad->handle, hwparams,
93 SND_PCM_ACCESS_RW_INTERLEAVED);
96 msg = "sample format not available";
97 ret = snd_pcm_hw_params_set_format(pad->handle, hwparams,
101 msg = "channels count not available";
102 ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams,
106 msg = "could not set sample rate";
107 ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
108 &pad->sample_rate, NULL);
111 msg = "unable to get buffer time";
112 ret = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time,
114 if (ret < 0 || buffer_time == 0)
116 /* buffer at most 500 milliseconds */
117 buffer_time = PARA_MIN(buffer_time, 500U * 1000U);
118 msg = "could not set buffer time";
119 ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
123 msg = "unable to install hw params";
124 ret = snd_pcm_hw_params(pad->handle, hwparams);
127 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
128 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
129 msg = "period size equals buffer size";
130 if (period_size == buffer_size)
133 /* software parameter setup */
134 snd_pcm_sw_params_alloca(&swparams);
135 snd_pcm_sw_params_current(pad->handle, swparams);
136 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
140 start_threshold = PARA_MIN(buffer_size,
141 (snd_pcm_uframes_t)pad->sample_rate);
142 msg = "could not set start threshold";
143 ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
147 stop_threshold = buffer_size;
148 msg = "could not set stop threshold";
149 ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
153 msg = "unable to install sw params";
154 ret = snd_pcm_sw_params(pad->handle, swparams);
157 msg = "unable to determine bytes per frame";
158 ret = snd_pcm_format_physical_width(pad->sample_format);
161 pad->bytes_per_frame = ret * pad->channels / 8;
162 msg = "failed to set alsa handle to nonblock mode";
163 ret = snd_pcm_nonblock(pad->handle, 1);
166 ret = snd_output_buffer_open(&output_log);
169 PARA_INFO_LOG("dumping alsa configuration\n");
170 snd_pcm_dump(pad->handle, output_log);
171 snd_output_buffer_string(output_log, &buf);
173 char *p = strchr(buf, '\n');
174 if (!p) /* omit last output line, it's empty */
177 PARA_INFO_LOG("%s\n", buf);
180 snd_output_close(output_log);
185 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
187 PARA_ERROR_LOG("%s\n", msg);
191 static void alsa_write_pre_select(struct sched *s, struct task *t)
194 struct writer_node *wn = container_of(t, struct writer_node, task);
195 struct private_alsa_write_data *pad = wn->private_data;
196 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
207 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
210 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
212 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
217 pad->poll_fd = pfd.fd;
218 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
221 static void alsa_close(struct writer_node *wn)
223 struct private_alsa_write_data *pad = wn->private_data;
224 PARA_INFO_LOG("closing writer node %p\n", wn);
229 * It's OK to have a blocking operation here because we already made
230 * sure that the PCM output buffer is (nearly) empty.
232 snd_pcm_nonblock(pad->handle, 0);
233 snd_pcm_drain(pad->handle);
234 snd_pcm_close(pad->handle);
235 snd_config_update_free_global();
239 static void alsa_write_post_select(__a_unused struct sched *s,
242 struct writer_node *wn = container_of(t, struct writer_node, task);
243 struct private_alsa_write_data *pad = wn->private_data;
244 struct btr_node *btrn = wn->btrn;
247 snd_pcm_sframes_t frames;
252 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
255 btr_merge(btrn, wn->min_iqs);
256 bytes = btr_next_buffer(btrn, &data);
257 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
258 assert(btr_no_parent(btrn));
259 ret = -E_WRITE_COMMON_EOF;
262 /* wait until pending frames are played */
263 if (pad->drain_barrier.tv_sec == 0) {
264 PARA_DEBUG_LOG("waiting for device to drain\n");
265 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
266 &pad->drain_barrier);
269 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
276 if (bytes == 0) /* no data available */
278 pad = para_calloc(sizeof(*pad));
279 get_btr_sample_rate(btrn, &val);
280 pad->sample_rate = val;
281 get_btr_channels(btrn, &val);
283 get_btr_sample_format(btrn, &val);
284 pad->sample_format = get_alsa_pcm_format(val);
286 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
288 ret = alsa_init(pad, wn->conf);
293 wn->private_data = pad;
294 wn->min_iqs = pad->bytes_per_frame;
297 if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
299 frames = bytes / pad->bytes_per_frame;
300 frames = snd_pcm_writei(pad->handle, data, frames);
301 if (frames == 0 || frames == -EAGAIN) {
303 * The alsa poll fd was ready for IO but we failed to write to
304 * the alsa handle. This means another event is pending. We
305 * don't care about that but we have to dispatch the event in
306 * order to avoid a busy loop. So we simply read from the poll
310 if (read(pad->poll_fd, buf, 100))
315 btr_consume(btrn, frames * pad->bytes_per_frame);
318 if (frames == -EPIPE) {
319 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
320 snd_pcm_prepare(pad->handle);
323 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
327 btr_remove_node(&wn->btrn);
331 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
333 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
335 /* exits on errors */
336 alsa_write_cmdline_parser(argc, argv, conf);
340 static void alsa_free_config(void *conf)
342 alsa_write_cmdline_parser_free(conf);
346 * The init function of the alsa writer.
348 * \param w Pointer to the writer to initialize.
350 * \sa struct \ref writer.
352 void alsa_write_init(struct writer *w)
354 struct alsa_write_args_info dummy;
356 alsa_write_cmdline_parser_init(&dummy);
357 w->close = alsa_close;
358 w->pre_select = alsa_write_pre_select;
359 w->post_select = alsa_write_post_select;
360 w->parse_config_or_die = alsa_parse_config_or_die;
361 w->free_config = alsa_free_config;
362 w->help = (struct ggo_help) {
363 .short_help = alsa_write_args_info_help,
364 .detailed_help = alsa_write_args_info_detailed_help
366 alsa_write_cmdline_parser_free(&dummy);