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;
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 msg = "could not set buffer time";
117 ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
121 msg = "unable to install hw params";
122 ret = snd_pcm_hw_params(pad->handle, hwparams);
125 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
126 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
127 msg = "period size equals buffer size";
128 if (period_size == buffer_size)
131 /* software parameter setup */
132 snd_pcm_sw_params_alloca(&swparams);
133 snd_pcm_sw_params_current(pad->handle, swparams);
134 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
138 start_threshold = PARA_MIN(buffer_size,
139 (snd_pcm_uframes_t)pad->sample_rate);
140 msg = "could not set start threshold";
141 ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
145 stop_threshold = buffer_size;
146 msg = "could not set stop threshold";
147 ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
151 msg = "unable to install sw params";
152 ret = snd_pcm_sw_params(pad->handle, swparams);
155 msg = "unable to determine bytes per frame";
156 ret = snd_pcm_format_physical_width(pad->sample_format);
159 pad->bytes_per_frame = ret * pad->channels / 8;
160 msg = "failed to set alsa handle to nonblock mode";
161 ret = snd_pcm_nonblock(pad->handle, 1);
164 ret = snd_output_buffer_open(&log);
167 PARA_INFO_LOG("dumping alsa configuration\n");
168 snd_pcm_dump(pad->handle, log);
169 snd_output_buffer_string(log, &buf);
171 char *p = strchr(buf, '\n');
172 if (!p) /* omit last output line, it's empty */
175 PARA_INFO_LOG("%s\n", buf);
178 snd_output_close(log);
183 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
185 PARA_ERROR_LOG("%s\n", msg);
189 static void alsa_write_pre_select(struct sched *s, struct task *t)
192 struct writer_node *wn = container_of(t, struct writer_node, task);
193 struct private_alsa_write_data *pad = wn->private_data;
194 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
205 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
208 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
210 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
215 pad->poll_fd = pfd.fd;
216 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
219 static void alsa_close(struct writer_node *wn)
221 struct private_alsa_write_data *pad = wn->private_data;
222 PARA_INFO_LOG("closing writer node %p\n", wn);
227 * It's OK to have a blocking operation here because we already made
228 * sure that the PCM output buffer is (nearly) empty.
230 snd_pcm_nonblock(pad->handle, 0);
231 snd_pcm_drain(pad->handle);
232 snd_pcm_close(pad->handle);
233 snd_config_update_free_global();
237 static void alsa_write_post_select(__a_unused struct sched *s,
240 struct writer_node *wn = container_of(t, struct writer_node, task);
241 struct private_alsa_write_data *pad = wn->private_data;
242 struct btr_node *btrn = wn->btrn;
245 snd_pcm_sframes_t frames;
250 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
253 btr_merge(btrn, wn->min_iqs);
254 bytes = btr_next_buffer(btrn, &data);
255 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
256 assert(btr_no_parent(btrn));
257 ret = -E_WRITE_COMMON_EOF;
260 /* wait until pending frames are played */
261 if (pad->drain_barrier.tv_sec == 0) {
262 PARA_DEBUG_LOG("waiting for device to drain\n");
263 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
264 &pad->drain_barrier);
267 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
274 if (bytes == 0) /* no data available */
276 pad = para_calloc(sizeof(*pad));
277 get_btr_sample_rate(btrn, &val);
278 pad->sample_rate = val;
279 get_btr_channels(btrn, &val);
281 get_btr_sample_format(btrn, &val);
282 pad->sample_format = get_alsa_pcm_format(val);
284 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
286 ret = alsa_init(pad, wn->conf);
291 wn->private_data = pad;
292 wn->min_iqs = pad->bytes_per_frame;
295 if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
297 frames = bytes / pad->bytes_per_frame;
298 frames = snd_pcm_writei(pad->handle, data, frames);
299 if (frames == 0 || frames == -EAGAIN) {
301 * The alsa poll fd was ready for IO but we failed to write to
302 * the alsa handle. This means another event is pending. We
303 * don't care about that but we have to dispatch the event in
304 * order to avoid a busy loop. So we simply read from the poll
308 if (read(pad->poll_fd, buf, 100))
313 btr_consume(btrn, frames * pad->bytes_per_frame);
316 if (frames == -EPIPE) {
317 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
318 snd_pcm_prepare(pad->handle);
321 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
325 btr_remove_node(btrn);
329 __malloc static void *alsa_parse_config_or_die(const char *options)
331 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
333 /* exits on errors */
334 alsa_cmdline_parser_string(options, conf, "alsa_write");
338 static void alsa_free_config(void *conf)
340 alsa_cmdline_parser_free(conf);
344 * The init function of the alsa writer.
346 * \param w Pointer to the writer to initialize.
348 * \sa struct \ref writer.
350 void alsa_write_init(struct writer *w)
352 struct alsa_write_args_info dummy;
354 alsa_cmdline_parser_init(&dummy);
355 w->close = alsa_close;
356 w->pre_select = alsa_write_pre_select;
357 w->post_select = alsa_write_post_select;
358 w->parse_config_or_die = alsa_parse_config_or_die;
359 w->shutdown = NULL; /* nothing to do */
360 w->free_config = alsa_free_config;
361 w->help = (struct ggo_help) {
362 .short_help = alsa_write_args_info_help,
363 .detailed_help = alsa_write_args_info_detailed_help
365 alsa_cmdline_parser_free(&dummy);