2 * This file is part of DisOrder
3 * Copyright (C) 2005, 2006, 2007 Richard Kettlewell
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.
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.
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
20 /** @file server/speaker-alsa.c
21 * @brief Support for @ref BACKEND_ALSA */
25 #if HAVE_ALSA_ASOUNDLIB_H
29 #include <alsa/asoundlib.h>
31 #include "configuration.h"
34 #include "speaker-protocol.h"
37 /** @brief The current PCM handle */
38 static snd_pcm_t *pcm;
40 /** @brief Last seen buffer size */
41 static snd_pcm_uframes_t last_pcm_bufsize;
43 /** @brief ALSA backend initialization */
44 static void alsa_init(void) {
45 info("selected ALSA backend");
48 /** @brief Log ALSA parameters */
49 static void log_params(snd_pcm_hw_params_t *hwparams,
50 snd_pcm_sw_params_t *swparams) {
54 return; /* too verbose */
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);
63 snd_pcm_sw_params_get_sleep_min(swparams, &u);
64 info("sw sleep_min=%lu", (unsigned long)u);
65 snd_pcm_sw_params_get_start_threshold(swparams, &f);
66 info("sw start_threshold=%lu", (unsigned long)f);
67 snd_pcm_sw_params_get_stop_threshold(swparams, &f);
68 info("sw stop_threshold=%lu", (unsigned long)f);
69 snd_pcm_sw_params_get_xfer_align(swparams, &f);
70 info("sw xfer_align=%lu", (unsigned long)f);
74 /** @brief ALSA deactivation */
75 static void alsa_deactivate(void) {
79 if((err = snd_pcm_nonblock(pcm, 0)) < 0)
80 fatal(0, "error calling snd_pcm_nonblock: %d", err);
86 device_state = device_closed;
87 D(("released audio device"));
91 /** @brief ALSA backend activation */
92 static void alsa_activate(void) {
94 snd_pcm_hw_params_t *hwparams;
95 snd_pcm_sw_params_t *swparams;
96 snd_pcm_uframes_t pcm_bufsize;
98 int sample_format = 0;
102 if((err = snd_pcm_open(&pcm,
104 SND_PCM_STREAM_PLAYBACK,
105 SND_PCM_NONBLOCK))) {
106 error(0, "error from snd_pcm_open: %d", err);
109 snd_pcm_hw_params_alloca(&hwparams);
110 D(("set up hw params"));
111 if((err = snd_pcm_hw_params_any(pcm, hwparams)) < 0)
112 fatal(0, "error from snd_pcm_hw_params_any: %d", err);
113 if((err = snd_pcm_hw_params_set_access(pcm, hwparams,
114 SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
115 fatal(0, "error from snd_pcm_hw_params_set_access: %d", err);
116 switch(config->sample_format.bits) {
118 sample_format = SND_PCM_FORMAT_S8;
121 switch(config->sample_format.endian) {
122 case ENDIAN_LITTLE: sample_format = SND_PCM_FORMAT_S16_LE; break;
123 case ENDIAN_BIG: sample_format = SND_PCM_FORMAT_S16_BE; break;
125 error(0, "unrecognized byte format %d", config->sample_format.endian);
130 error(0, "unsupported sample size %d", config->sample_format.bits);
133 if((err = snd_pcm_hw_params_set_format(pcm, hwparams,
134 sample_format)) < 0) {
135 error(0, "error from snd_pcm_hw_params_set_format (%d): %d",
139 rate = config->sample_format.rate;
140 if((err = snd_pcm_hw_params_set_rate_near(pcm, hwparams, &rate, 0)) < 0) {
141 error(0, "error from snd_pcm_hw_params_set_rate (%d): %d",
142 config->sample_format.rate, err);
145 if(rate != (unsigned)config->sample_format.rate)
146 info("want rate %d, got %u", config->sample_format.rate, rate);
147 if((err = snd_pcm_hw_params_set_channels
148 (pcm, hwparams, config->sample_format.channels)) < 0) {
149 error(0, "error from snd_pcm_hw_params_set_channels (%d): %d",
150 config->sample_format.channels, err);
153 pcm_bufsize = 3 * FRAMES;
154 if((err = snd_pcm_hw_params_set_buffer_size_near(pcm, hwparams,
156 fatal(0, "error from snd_pcm_hw_params_set_buffer_size (%d): %d",
158 if(pcm_bufsize != 3 * FRAMES && pcm_bufsize != last_pcm_bufsize)
159 info("asked for PCM buffer of %d frames, got %d",
160 3 * FRAMES, (int)pcm_bufsize);
161 last_pcm_bufsize = pcm_bufsize;
162 if((err = snd_pcm_hw_params(pcm, hwparams)) < 0)
163 fatal(0, "error calling snd_pcm_hw_params: %d", err);
164 D(("set up sw params"));
165 snd_pcm_sw_params_alloca(&swparams);
166 if((err = snd_pcm_sw_params_current(pcm, swparams)) < 0)
167 fatal(0, "error calling snd_pcm_sw_params_current: %d", err);
168 if((err = snd_pcm_sw_params_set_avail_min(pcm, swparams, FRAMES)) < 0)
169 fatal(0, "error calling snd_pcm_sw_params_set_avail_min %d: %d",
171 if((err = snd_pcm_sw_params(pcm, swparams)) < 0)
172 fatal(0, "error calling snd_pcm_sw_params: %d", err);
173 D(("acquired audio device"));
174 log_params(hwparams, swparams);
175 device_state = device_open;
181 /* We assume the error is temporary and that we'll retry in a bit. */
185 device_state = device_error;
190 /** @brief Play via ALSA */
191 static size_t alsa_play(size_t frames) {
192 snd_pcm_sframes_t pcm_written_frames;
195 pcm_written_frames = snd_pcm_writei(pcm,
196 playing->buffer + playing->start,
198 D(("actually play %zu frames, wrote %d",
199 frames, (int)pcm_written_frames));
200 if(pcm_written_frames < 0) {
201 switch(pcm_written_frames) {
202 case -EPIPE: /* underrun */
203 error(0, "snd_pcm_writei reports underrun");
204 if((err = snd_pcm_prepare(pcm)) < 0)
205 fatal(0, "error calling snd_pcm_prepare: %d", err);
210 fatal(0, "error calling snd_pcm_writei: %d",
211 (int)pcm_written_frames);
214 return pcm_written_frames;
217 static int alsa_slots, alsa_nslots = -1;
219 /** @brief Fill in poll fd array for ALSA */
220 static void alsa_beforepoll(int attribute((unused)) *timeoutp) {
221 /* We send sample data to ALSA as fast as it can accept it, relying on
222 * the fact that it has a relatively small buffer to minimize pause
229 alsa_nslots = snd_pcm_poll_descriptors(pcm, &fds[fdno], NFDS - fdno);
231 || !(fds[alsa_slots].events & POLLOUT))
232 && snd_pcm_state(pcm) == SND_PCM_STATE_XRUN) {
233 error(0, "underrun detected after call to snd_pcm_poll_descriptors()");
234 if((err = snd_pcm_prepare(pcm)))
235 fatal(0, "error calling snd_pcm_prepare: %d", err);
238 } while(retry-- > 0);
243 /** @brief Process poll() results for ALSA */
244 static int alsa_ready(void) {
247 unsigned short alsa_revents;
249 if((err = snd_pcm_poll_descriptors_revents(pcm,
253 fatal(0, "error calling snd_pcm_poll_descriptors_revents: %d", err);
254 if(alsa_revents & (POLLOUT | POLLERR))
260 const struct speaker_backend alsa_backend = {