chiark / gitweb /
Don't use deprecated ALSA calls (since they generate warnings, which
[disorder] / server / speaker-alsa.c
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1c3f1e73 1/*
2 * This file is part of DisOrder
3 * Copyright (C) 2005, 2006, 2007 Richard Kettlewell
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
20/** @file server/speaker-alsa.c
21 * @brief Support for @ref BACKEND_ALSA */
22
05b75f8d 23#include "common.h"
1c3f1e73 24
146e86fb 25#if HAVE_ALSA_ASOUNDLIB_H
1c3f1e73 26
1c3f1e73 27#include <unistd.h>
28#include <poll.h>
29#include <alsa/asoundlib.h>
30
31#include "configuration.h"
32#include "syscalls.h"
33#include "log.h"
34#include "speaker-protocol.h"
35#include "speaker.h"
36
37/** @brief The current PCM handle */
38static snd_pcm_t *pcm;
39
40/** @brief Last seen buffer size */
41static snd_pcm_uframes_t last_pcm_bufsize;
42
43/** @brief ALSA backend initialization */
44static void alsa_init(void) {
45 info("selected ALSA backend");
46}
47
48/** @brief Log ALSA parameters */
49static void log_params(snd_pcm_hw_params_t *hwparams,
50 snd_pcm_sw_params_t *swparams) {
51 snd_pcm_uframes_t f;
52 unsigned u;
53
54 return; /* too verbose */
55 if(hwparams) {
56 /* TODO */
57 }
58 if(swparams) {
59 snd_pcm_sw_params_get_silence_size(swparams, &f);
60 info("sw silence_size=%lu", (unsigned long)f);
61 snd_pcm_sw_params_get_silence_threshold(swparams, &f);
62 info("sw silence_threshold=%lu", (unsigned long)f);
cf7ca906 63#if HAVE_SND_PCM_SW_PARAMS_GET_SLEEP_MIN
1c3f1e73 64 snd_pcm_sw_params_get_sleep_min(swparams, &u);
65 info("sw sleep_min=%lu", (unsigned long)u);
cf7ca906 66#endif
1c3f1e73 67 snd_pcm_sw_params_get_start_threshold(swparams, &f);
68 info("sw start_threshold=%lu", (unsigned long)f);
69 snd_pcm_sw_params_get_stop_threshold(swparams, &f);
70 info("sw stop_threshold=%lu", (unsigned long)f);
cf7ca906 71#if HAVE_SND_PCM_SW_PARAMS_GET_XFER_ALIGN
1c3f1e73 72 snd_pcm_sw_params_get_xfer_align(swparams, &f);
73 info("sw xfer_align=%lu", (unsigned long)f);
cf7ca906 74#endif
1c3f1e73 75 }
76}
77
78/** @brief ALSA deactivation */
79static void alsa_deactivate(void) {
80 if(pcm) {
81 int err;
82
83 if((err = snd_pcm_nonblock(pcm, 0)) < 0)
84 fatal(0, "error calling snd_pcm_nonblock: %d", err);
85 D(("draining pcm"));
86 snd_pcm_drain(pcm);
87 D(("closing pcm"));
88 snd_pcm_close(pcm);
89 pcm = 0;
90 device_state = device_closed;
91 D(("released audio device"));
92 }
93}
94
95/** @brief ALSA backend activation */
96static void alsa_activate(void) {
1c3f1e73 97 if(!pcm) {
98 snd_pcm_hw_params_t *hwparams;
99 snd_pcm_sw_params_t *swparams;
100 snd_pcm_uframes_t pcm_bufsize;
101 int err;
102 int sample_format = 0;
103 unsigned rate;
104
105 D(("snd_pcm_open"));
106 if((err = snd_pcm_open(&pcm,
107 config->device,
108 SND_PCM_STREAM_PLAYBACK,
109 SND_PCM_NONBLOCK))) {
110 error(0, "error from snd_pcm_open: %d", err);
111 goto error;
112 }
113 snd_pcm_hw_params_alloca(&hwparams);
114 D(("set up hw params"));
115 if((err = snd_pcm_hw_params_any(pcm, hwparams)) < 0)
116 fatal(0, "error from snd_pcm_hw_params_any: %d", err);
117 if((err = snd_pcm_hw_params_set_access(pcm, hwparams,
118 SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
119 fatal(0, "error from snd_pcm_hw_params_set_access: %d", err);
6d2d327c 120 switch(config->sample_format.bits) {
1c3f1e73 121 case 8:
122 sample_format = SND_PCM_FORMAT_S8;
123 break;
124 case 16:
6d2d327c
RK
125 switch(config->sample_format.endian) {
126 case ENDIAN_LITTLE: sample_format = SND_PCM_FORMAT_S16_LE; break;
127 case ENDIAN_BIG: sample_format = SND_PCM_FORMAT_S16_BE; break;
128 default:
129 error(0, "unrecognized byte format %d", config->sample_format.endian);
1c3f1e73 130 goto fatal;
131 }
132 break;
133 default:
6d2d327c 134 error(0, "unsupported sample size %d", config->sample_format.bits);
1c3f1e73 135 goto fatal;
136 }
137 if((err = snd_pcm_hw_params_set_format(pcm, hwparams,
138 sample_format)) < 0) {
139 error(0, "error from snd_pcm_hw_params_set_format (%d): %d",
140 sample_format, err);
141 goto fatal;
142 }
6d2d327c 143 rate = config->sample_format.rate;
1c3f1e73 144 if((err = snd_pcm_hw_params_set_rate_near(pcm, hwparams, &rate, 0)) < 0) {
145 error(0, "error from snd_pcm_hw_params_set_rate (%d): %d",
6d2d327c 146 config->sample_format.rate, err);
1c3f1e73 147 goto fatal;
148 }
6d2d327c
RK
149 if(rate != (unsigned)config->sample_format.rate)
150 info("want rate %d, got %u", config->sample_format.rate, rate);
151 if((err = snd_pcm_hw_params_set_channels
152 (pcm, hwparams, config->sample_format.channels)) < 0) {
1c3f1e73 153 error(0, "error from snd_pcm_hw_params_set_channels (%d): %d",
6d2d327c 154 config->sample_format.channels, err);
1c3f1e73 155 goto fatal;
156 }
157 pcm_bufsize = 3 * FRAMES;
158 if((err = snd_pcm_hw_params_set_buffer_size_near(pcm, hwparams,
159 &pcm_bufsize)) < 0)
160 fatal(0, "error from snd_pcm_hw_params_set_buffer_size (%d): %d",
161 3 * FRAMES, err);
162 if(pcm_bufsize != 3 * FRAMES && pcm_bufsize != last_pcm_bufsize)
163 info("asked for PCM buffer of %d frames, got %d",
164 3 * FRAMES, (int)pcm_bufsize);
165 last_pcm_bufsize = pcm_bufsize;
166 if((err = snd_pcm_hw_params(pcm, hwparams)) < 0)
167 fatal(0, "error calling snd_pcm_hw_params: %d", err);
168 D(("set up sw params"));
169 snd_pcm_sw_params_alloca(&swparams);
170 if((err = snd_pcm_sw_params_current(pcm, swparams)) < 0)
171 fatal(0, "error calling snd_pcm_sw_params_current: %d", err);
172 if((err = snd_pcm_sw_params_set_avail_min(pcm, swparams, FRAMES)) < 0)
173 fatal(0, "error calling snd_pcm_sw_params_set_avail_min %d: %d",
174 FRAMES, err);
175 if((err = snd_pcm_sw_params(pcm, swparams)) < 0)
176 fatal(0, "error calling snd_pcm_sw_params: %d", err);
1c3f1e73 177 D(("acquired audio device"));
178 log_params(hwparams, swparams);
179 device_state = device_open;
180 }
181 return;
182fatal:
183 abandon();
184error:
185 /* We assume the error is temporary and that we'll retry in a bit. */
186 if(pcm) {
187 snd_pcm_close(pcm);
188 pcm = 0;
189 device_state = device_error;
190 }
191 return;
192}
193
194/** @brief Play via ALSA */
195static size_t alsa_play(size_t frames) {
196 snd_pcm_sframes_t pcm_written_frames;
197 int err;
198
199 pcm_written_frames = snd_pcm_writei(pcm,
200 playing->buffer + playing->start,
201 frames);
202 D(("actually play %zu frames, wrote %d",
203 frames, (int)pcm_written_frames));
204 if(pcm_written_frames < 0) {
205 switch(pcm_written_frames) {
206 case -EPIPE: /* underrun */
207 error(0, "snd_pcm_writei reports underrun");
208 if((err = snd_pcm_prepare(pcm)) < 0)
209 fatal(0, "error calling snd_pcm_prepare: %d", err);
210 return 0;
211 case -EAGAIN:
212 return 0;
213 default:
214 fatal(0, "error calling snd_pcm_writei: %d",
215 (int)pcm_written_frames);
216 }
217 } else
218 return pcm_written_frames;
219}
220
221static int alsa_slots, alsa_nslots = -1;
222
223/** @brief Fill in poll fd array for ALSA */
e84fb5f0 224static void alsa_beforepoll(int attribute((unused)) *timeoutp) {
1c3f1e73 225 /* We send sample data to ALSA as fast as it can accept it, relying on
226 * the fact that it has a relatively small buffer to minimize pause
227 * latency. */
228 int retry = 3, err;
229
230 alsa_slots = fdno;
231 do {
232 retry = 0;
233 alsa_nslots = snd_pcm_poll_descriptors(pcm, &fds[fdno], NFDS - fdno);
234 if((alsa_nslots <= 0
235 || !(fds[alsa_slots].events & POLLOUT))
236 && snd_pcm_state(pcm) == SND_PCM_STATE_XRUN) {
237 error(0, "underrun detected after call to snd_pcm_poll_descriptors()");
238 if((err = snd_pcm_prepare(pcm)))
239 fatal(0, "error calling snd_pcm_prepare: %d", err);
240 } else
241 break;
242 } while(retry-- > 0);
243 if(alsa_nslots >= 0)
244 fdno += alsa_nslots;
245}
246
247/** @brief Process poll() results for ALSA */
248static int alsa_ready(void) {
249 int err;
250
251 unsigned short alsa_revents;
252
253 if((err = snd_pcm_poll_descriptors_revents(pcm,
254 &fds[alsa_slots],
255 alsa_nslots,
256 &alsa_revents)) < 0)
257 fatal(0, "error calling snd_pcm_poll_descriptors_revents: %d", err);
258 if(alsa_revents & (POLLOUT | POLLERR))
259 return 1;
260 else
261 return 0;
262}
263
264const struct speaker_backend alsa_backend = {
265 BACKEND_ALSA,
266 0,
267 alsa_init,
268 alsa_activate,
269 alsa_play,
270 alsa_deactivate,
271 alsa_beforepoll,
272 alsa_ready
273};
274
275#endif
276
277/*
278Local Variables:
279c-basic-offset:2
280comment-column:40
281fill-column:79
282indent-tabs-mode:nil
283End:
284*/