2 * Copyright (C) 2005-2011 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>
27 #include "buffer_tree.h"
29 #include "write_common.h"
30 #include "alsa_write.cmdline.h"
33 /** Data specific to the alsa writer. */
34 struct private_alsa_write_data
{
35 /** The alsa handle */
37 /** Determined and set by alsa_init(). */
40 * The sample rate given by command line option or the decoder
41 * of the writer node group.
44 snd_pcm_format_t sample_format
;
46 * The number of channels, given by command line option or the
47 * decoder of the writer node group.
50 struct timeval drain_barrier
;
51 /* File descriptor for select(). */
55 static snd_pcm_format_t
get_alsa_pcm_format(enum sample_format sf
)
58 case SF_S8
: return SND_PCM_FORMAT_S8
;
59 case SF_U8
: return SND_PCM_FORMAT_U8
;
60 case SF_S16_LE
: return SND_PCM_FORMAT_S16_LE
;
61 case SF_S16_BE
: return SND_PCM_FORMAT_S16_BE
;
62 case SF_U16_LE
: return SND_PCM_FORMAT_U16_LE
;
63 case SF_U16_BE
: return SND_PCM_FORMAT_U16_BE
;
64 default: return SND_PCM_FORMAT_S16_LE
;
68 /* Install PCM software and hardware configuration. */
69 static int alsa_init(struct private_alsa_write_data
*pad
,
70 struct alsa_write_args_info
*conf
)
72 snd_pcm_hw_params_t
*hwparams
;
73 snd_pcm_sw_params_t
*swparams
;
74 snd_pcm_uframes_t start_threshold
, stop_threshold
;
75 snd_pcm_uframes_t buffer_size
, period_size
;
81 PARA_INFO_LOG("opening %s\n", conf
->device_arg
);
82 msg
= "unable to open pcm";
83 ret
= snd_pcm_open(&pad
->handle
, conf
->device_arg
,
84 SND_PCM_STREAM_PLAYBACK
, SND_PCM_NONBLOCK
);
87 snd_pcm_hw_params_alloca(&hwparams
);
88 msg
= "Broken alsa configuration";
89 ret
= snd_pcm_hw_params_any(pad
->handle
, hwparams
);
92 msg
= "access type not available";
93 ret
= snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
94 SND_PCM_ACCESS_RW_INTERLEAVED
);
97 msg
= "sample format not available";
98 ret
= snd_pcm_hw_params_set_format(pad
->handle
, hwparams
,
102 msg
= "channels count not available";
103 ret
= snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
107 msg
= "could not set sample rate";
108 ret
= snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
109 &pad
->sample_rate
, NULL
);
112 msg
= "unable to get buffer time";
113 ret
= snd_pcm_hw_params_get_buffer_time_max(hwparams
, &buffer_time
,
115 if (ret
< 0 || buffer_time
== 0)
117 msg
= "could not set buffer time";
118 ret
= snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
122 msg
= "unable to install hw params";
123 ret
= snd_pcm_hw_params(pad
->handle
, hwparams
);
126 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, NULL
);
127 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
128 msg
= "period size equals buffer size";
129 if (period_size
== buffer_size
)
132 /* software parameter setup */
133 snd_pcm_sw_params_alloca(&swparams
);
134 snd_pcm_sw_params_current(pad
->handle
, swparams
);
135 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
139 start_threshold
= PARA_MIN(buffer_size
,
140 (snd_pcm_uframes_t
)pad
->sample_rate
);
141 msg
= "could not set start threshold";
142 ret
= snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
146 stop_threshold
= buffer_size
;
147 msg
= "could not set stop threshold";
148 ret
= snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
152 msg
= "unable to install sw params";
153 ret
= snd_pcm_sw_params(pad
->handle
, swparams
);
156 msg
= "unable to determine bytes per frame";
157 ret
= snd_pcm_format_physical_width(pad
->sample_format
);
160 pad
->bytes_per_frame
= ret
* pad
->channels
/ 8;
161 msg
= "failed to set alsa handle to nonblock mode";
162 ret
= snd_pcm_nonblock(pad
->handle
, 1);
165 ret
= snd_output_buffer_open(&log
);
168 PARA_INFO_LOG("dumping alsa configuration\n");
169 snd_pcm_dump(pad
->handle
, log
);
170 snd_output_buffer_string(log
, &buf
);
172 char *p
= strchr(buf
, '\n');
173 if (!p
) /* omit last output line, it's empty */
176 PARA_INFO_LOG("%s\n", buf
);
179 snd_output_close(log
);
184 PARA_ERROR_LOG("%s: %s\n", msg
, snd_strerror(-ret
));
186 PARA_ERROR_LOG("%s\n", msg
);
190 static void alsa_write_pre_select(struct sched
*s
, struct task
*t
)
193 struct writer_node
*wn
= container_of(t
, struct writer_node
, task
);
194 struct private_alsa_write_data
*pad
= wn
->private_data
;
195 int ret
= btr_node_status(wn
->btrn
, wn
->min_iqs
, BTR_NT_LEAF
);
206 sched_request_barrier_or_min_delay(&pad
->drain_barrier
, s
);
209 ret
= snd_pcm_poll_descriptors(pad
->handle
, &pfd
, 1);
211 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
216 pad
->poll_fd
= pfd
.fd
;
217 para_fd_set(pfd
.fd
, &s
->rfds
, &s
->max_fileno
);
220 static void alsa_close(struct writer_node
*wn
)
222 struct private_alsa_write_data
*pad
= wn
->private_data
;
223 PARA_INFO_LOG("closing writer node %p\n", wn
);
228 * It's OK to have a blocking operation here because we already made
229 * sure that the PCM output buffer is (nearly) empty.
231 snd_pcm_nonblock(pad
->handle
, 0);
232 snd_pcm_drain(pad
->handle
);
233 snd_pcm_close(pad
->handle
);
234 snd_config_update_free_global();
238 static void alsa_write_post_select(__a_unused
struct sched
*s
,
241 struct writer_node
*wn
= container_of(t
, struct writer_node
, task
);
242 struct private_alsa_write_data
*pad
= wn
->private_data
;
243 struct btr_node
*btrn
= wn
->btrn
;
246 snd_pcm_sframes_t frames
;
251 ret
= btr_node_status(btrn
, wn
->min_iqs
, BTR_NT_LEAF
);
254 btr_merge(btrn
, wn
->min_iqs
);
255 bytes
= btr_next_buffer(btrn
, &data
);
256 if (ret
< 0 || bytes
< wn
->min_iqs
) { /* eof */
257 assert(btr_no_parent(btrn
));
258 ret
= -E_WRITE_COMMON_EOF
;
261 /* wait until pending frames are played */
262 if (pad
->drain_barrier
.tv_sec
== 0) {
263 PARA_DEBUG_LOG("waiting for device to drain\n");
264 tv_add(now
, &(struct timeval
)EMBRACE(0, 200 * 1000),
265 &pad
->drain_barrier
);
268 if (tv_diff(now
, &pad
->drain_barrier
, NULL
) > 0)
275 if (bytes
== 0) /* no data available */
277 pad
= para_calloc(sizeof(*pad
));
278 get_btr_sample_rate(btrn
, &val
);
279 pad
->sample_rate
= val
;
280 get_btr_channels(btrn
, &val
);
282 get_btr_sample_format(btrn
, &val
);
283 pad
->sample_format
= get_alsa_pcm_format(val
);
285 PARA_INFO_LOG("%d channel(s), %dHz\n", pad
->channels
,
287 ret
= alsa_init(pad
, wn
->conf
);
292 wn
->private_data
= pad
;
293 wn
->min_iqs
= pad
->bytes_per_frame
;
296 if (pad
->poll_fd
< 0 || !FD_ISSET(pad
->poll_fd
, &s
->rfds
))
298 frames
= bytes
/ pad
->bytes_per_frame
;
299 frames
= snd_pcm_writei(pad
->handle
, data
, frames
);
300 if (frames
== 0 || frames
== -EAGAIN
) {
302 * The alsa poll fd was ready for IO but we failed to write to
303 * the alsa handle. This means another event is pending. We
304 * don't care about that but we have to dispatch the event in
305 * order to avoid a busy loop. So we simply read from the poll
309 if (read(pad
->poll_fd
, buf
, 100))
314 btr_consume(btrn
, frames
* pad
->bytes_per_frame
);
317 if (frames
== -EPIPE
) {
318 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes
);
319 snd_pcm_prepare(pad
->handle
);
322 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames
));
326 btr_remove_node(btrn
);
330 __malloc
static void *alsa_parse_config_or_die(const char *options
)
332 struct alsa_write_args_info
*conf
= para_calloc(sizeof(*conf
));
334 /* exits on errors */
335 alsa_cmdline_parser_string(options
, conf
, "alsa_write");
339 static void alsa_free_config(void *conf
)
341 alsa_cmdline_parser_free(conf
);
345 * The init function of the alsa writer.
347 * \param w Pointer to the writer to initialize.
349 * \sa struct \ref writer.
351 void alsa_write_init(struct writer
*w
)
353 struct alsa_write_args_info dummy
;
355 alsa_cmdline_parser_init(&dummy
);
356 w
->close
= alsa_close
;
357 w
->pre_select
= alsa_write_pre_select
;
358 w
->post_select
= alsa_write_post_select
;
359 w
->parse_config_or_die
= alsa_parse_config_or_die
;
360 w
->shutdown
= NULL
; /* nothing to do */
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_cmdline_parser_free(&dummy
);