| 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 3 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, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU 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, see <http://www.gnu.org/licenses/>. |
| 17 | */ |
| 18 | /** @file server/speaker-alsa.c |
| 19 | * @brief Support for @ref BACKEND_ALSA */ |
| 20 | |
| 21 | #include "common.h" |
| 22 | |
| 23 | #if HAVE_ALSA_ASOUNDLIB_H |
| 24 | |
| 25 | #include <unistd.h> |
| 26 | #include <poll.h> |
| 27 | #include <alsa/asoundlib.h> |
| 28 | |
| 29 | #include "configuration.h" |
| 30 | #include "syscalls.h" |
| 31 | #include "log.h" |
| 32 | #include "speaker-protocol.h" |
| 33 | #include "speaker.h" |
| 34 | |
| 35 | /** @brief The current PCM handle */ |
| 36 | static snd_pcm_t *pcm; |
| 37 | |
| 38 | /** @brief Last seen buffer size */ |
| 39 | static snd_pcm_uframes_t last_pcm_bufsize; |
| 40 | |
| 41 | /** @brief ALSA backend initialization */ |
| 42 | static void alsa_init(void) { |
| 43 | info("selected ALSA backend"); |
| 44 | } |
| 45 | |
| 46 | /** @brief Log ALSA parameters */ |
| 47 | static void log_params(snd_pcm_hw_params_t *hwparams, |
| 48 | snd_pcm_sw_params_t *swparams) { |
| 49 | snd_pcm_uframes_t f; |
| 50 | |
| 51 | return; /* too verbose */ |
| 52 | if(hwparams) { |
| 53 | /* TODO */ |
| 54 | } |
| 55 | if(swparams) { |
| 56 | snd_pcm_sw_params_get_silence_size(swparams, &f); |
| 57 | info("sw silence_size=%lu", (unsigned long)f); |
| 58 | snd_pcm_sw_params_get_silence_threshold(swparams, &f); |
| 59 | info("sw silence_threshold=%lu", (unsigned long)f); |
| 60 | #if HAVE_SND_PCM_SW_PARAMS_GET_SLEEP_MIN |
| 61 | { |
| 62 | unsigned u; |
| 63 | |
| 64 | snd_pcm_sw_params_get_sleep_min(swparams, &u); |
| 65 | info("sw sleep_min=%lu", (unsigned long)u); |
| 66 | } |
| 67 | #endif |
| 68 | snd_pcm_sw_params_get_start_threshold(swparams, &f); |
| 69 | info("sw start_threshold=%lu", (unsigned long)f); |
| 70 | snd_pcm_sw_params_get_stop_threshold(swparams, &f); |
| 71 | info("sw stop_threshold=%lu", (unsigned long)f); |
| 72 | #if HAVE_SND_PCM_SW_PARAMS_GET_XFER_ALIGN |
| 73 | snd_pcm_sw_params_get_xfer_align(swparams, &f); |
| 74 | info("sw xfer_align=%lu", (unsigned long)f); |
| 75 | #endif |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | /** @brief ALSA deactivation */ |
| 80 | static void alsa_deactivate(void) { |
| 81 | if(pcm) { |
| 82 | int err; |
| 83 | |
| 84 | if((err = snd_pcm_nonblock(pcm, 0)) < 0) |
| 85 | fatal(0, "error calling snd_pcm_nonblock: %d", err); |
| 86 | D(("draining pcm")); |
| 87 | snd_pcm_drain(pcm); |
| 88 | D(("closing pcm")); |
| 89 | snd_pcm_close(pcm); |
| 90 | pcm = 0; |
| 91 | device_state = device_closed; |
| 92 | D(("released audio device")); |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | /** @brief ALSA backend activation */ |
| 97 | static void alsa_activate(void) { |
| 98 | if(!pcm) { |
| 99 | snd_pcm_hw_params_t *hwparams; |
| 100 | snd_pcm_sw_params_t *swparams; |
| 101 | snd_pcm_uframes_t pcm_bufsize; |
| 102 | int err; |
| 103 | int sample_format = 0; |
| 104 | unsigned rate; |
| 105 | |
| 106 | D(("snd_pcm_open")); |
| 107 | if((err = snd_pcm_open(&pcm, |
| 108 | config->device, |
| 109 | SND_PCM_STREAM_PLAYBACK, |
| 110 | SND_PCM_NONBLOCK))) { |
| 111 | error(0, "error from snd_pcm_open: %d", err); |
| 112 | goto error; |
| 113 | } |
| 114 | snd_pcm_hw_params_alloca(&hwparams); |
| 115 | D(("set up hw params")); |
| 116 | if((err = snd_pcm_hw_params_any(pcm, hwparams)) < 0) |
| 117 | fatal(0, "error from snd_pcm_hw_params_any: %d", err); |
| 118 | if((err = snd_pcm_hw_params_set_access(pcm, hwparams, |
| 119 | SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) |
| 120 | fatal(0, "error from snd_pcm_hw_params_set_access: %d", err); |
| 121 | switch(config->sample_format.bits) { |
| 122 | case 8: |
| 123 | sample_format = SND_PCM_FORMAT_S8; |
| 124 | break; |
| 125 | case 16: |
| 126 | switch(config->sample_format.endian) { |
| 127 | case ENDIAN_LITTLE: sample_format = SND_PCM_FORMAT_S16_LE; break; |
| 128 | case ENDIAN_BIG: sample_format = SND_PCM_FORMAT_S16_BE; break; |
| 129 | default: |
| 130 | error(0, "unrecognized byte format %d", config->sample_format.endian); |
| 131 | goto fatal; |
| 132 | } |
| 133 | break; |
| 134 | default: |
| 135 | error(0, "unsupported sample size %d", config->sample_format.bits); |
| 136 | goto fatal; |
| 137 | } |
| 138 | if((err = snd_pcm_hw_params_set_format(pcm, hwparams, |
| 139 | sample_format)) < 0) { |
| 140 | error(0, "error from snd_pcm_hw_params_set_format (%d): %d", |
| 141 | sample_format, err); |
| 142 | goto fatal; |
| 143 | } |
| 144 | rate = config->sample_format.rate; |
| 145 | if((err = snd_pcm_hw_params_set_rate_near(pcm, hwparams, &rate, 0)) < 0) { |
| 146 | error(0, "error from snd_pcm_hw_params_set_rate (%d): %d", |
| 147 | config->sample_format.rate, err); |
| 148 | goto fatal; |
| 149 | } |
| 150 | if(rate != (unsigned)config->sample_format.rate) |
| 151 | info("want rate %d, got %u", config->sample_format.rate, rate); |
| 152 | if((err = snd_pcm_hw_params_set_channels |
| 153 | (pcm, hwparams, config->sample_format.channels)) < 0) { |
| 154 | error(0, "error from snd_pcm_hw_params_set_channels (%d): %d", |
| 155 | config->sample_format.channels, err); |
| 156 | goto fatal; |
| 157 | } |
| 158 | pcm_bufsize = 3 * FRAMES; |
| 159 | if((err = snd_pcm_hw_params_set_buffer_size_near(pcm, hwparams, |
| 160 | &pcm_bufsize)) < 0) |
| 161 | fatal(0, "error from snd_pcm_hw_params_set_buffer_size (%d): %d", |
| 162 | 3 * FRAMES, err); |
| 163 | if(pcm_bufsize != 3 * FRAMES && pcm_bufsize != last_pcm_bufsize) |
| 164 | info("asked for PCM buffer of %d frames, got %d", |
| 165 | 3 * FRAMES, (int)pcm_bufsize); |
| 166 | last_pcm_bufsize = pcm_bufsize; |
| 167 | if((err = snd_pcm_hw_params(pcm, hwparams)) < 0) |
| 168 | fatal(0, "error calling snd_pcm_hw_params: %d", err); |
| 169 | D(("set up sw params")); |
| 170 | snd_pcm_sw_params_alloca(&swparams); |
| 171 | if((err = snd_pcm_sw_params_current(pcm, swparams)) < 0) |
| 172 | fatal(0, "error calling snd_pcm_sw_params_current: %d", err); |
| 173 | if((err = snd_pcm_sw_params_set_avail_min(pcm, swparams, FRAMES)) < 0) |
| 174 | fatal(0, "error calling snd_pcm_sw_params_set_avail_min %d: %d", |
| 175 | FRAMES, err); |
| 176 | if((err = snd_pcm_sw_params(pcm, swparams)) < 0) |
| 177 | fatal(0, "error calling snd_pcm_sw_params: %d", err); |
| 178 | D(("acquired audio device")); |
| 179 | log_params(hwparams, swparams); |
| 180 | device_state = device_open; |
| 181 | } |
| 182 | return; |
| 183 | fatal: |
| 184 | abandon(); |
| 185 | error: |
| 186 | /* We assume the error is temporary and that we'll retry in a bit. */ |
| 187 | if(pcm) { |
| 188 | snd_pcm_close(pcm); |
| 189 | pcm = 0; |
| 190 | device_state = device_error; |
| 191 | } |
| 192 | return; |
| 193 | } |
| 194 | |
| 195 | /** @brief Play via ALSA */ |
| 196 | static size_t alsa_play(size_t frames) { |
| 197 | snd_pcm_sframes_t pcm_written_frames; |
| 198 | int err; |
| 199 | |
| 200 | pcm_written_frames = snd_pcm_writei(pcm, |
| 201 | playing->buffer + playing->start, |
| 202 | frames); |
| 203 | D(("actually play %zu frames, wrote %d", |
| 204 | frames, (int)pcm_written_frames)); |
| 205 | if(pcm_written_frames < 0) { |
| 206 | switch(pcm_written_frames) { |
| 207 | case -EPIPE: /* underrun */ |
| 208 | error(0, "snd_pcm_writei reports underrun"); |
| 209 | if((err = snd_pcm_prepare(pcm)) < 0) |
| 210 | fatal(0, "error calling snd_pcm_prepare: %d", err); |
| 211 | return 0; |
| 212 | case -EAGAIN: |
| 213 | return 0; |
| 214 | default: |
| 215 | fatal(0, "error calling snd_pcm_writei: %d", |
| 216 | (int)pcm_written_frames); |
| 217 | } |
| 218 | } else |
| 219 | return pcm_written_frames; |
| 220 | } |
| 221 | |
| 222 | static int alsa_slots, alsa_nslots = -1; |
| 223 | |
| 224 | /** @brief Fill in poll fd array for ALSA */ |
| 225 | static void alsa_beforepoll(int attribute((unused)) *timeoutp) { |
| 226 | /* We send sample data to ALSA as fast as it can accept it, relying on |
| 227 | * the fact that it has a relatively small buffer to minimize pause |
| 228 | * latency. */ |
| 229 | int retry = 3, err; |
| 230 | |
| 231 | alsa_slots = fdno; |
| 232 | do { |
| 233 | retry = 0; |
| 234 | alsa_nslots = snd_pcm_poll_descriptors(pcm, &fds[fdno], NFDS - fdno); |
| 235 | if((alsa_nslots <= 0 |
| 236 | || !(fds[alsa_slots].events & POLLOUT)) |
| 237 | && snd_pcm_state(pcm) == SND_PCM_STATE_XRUN) { |
| 238 | error(0, "underrun detected after call to snd_pcm_poll_descriptors()"); |
| 239 | if((err = snd_pcm_prepare(pcm))) |
| 240 | fatal(0, "error calling snd_pcm_prepare: %d", err); |
| 241 | } else |
| 242 | break; |
| 243 | } while(retry-- > 0); |
| 244 | if(alsa_nslots >= 0) |
| 245 | fdno += alsa_nslots; |
| 246 | } |
| 247 | |
| 248 | /** @brief Process poll() results for ALSA */ |
| 249 | static int alsa_ready(void) { |
| 250 | int err; |
| 251 | |
| 252 | unsigned short alsa_revents; |
| 253 | |
| 254 | if((err = snd_pcm_poll_descriptors_revents(pcm, |
| 255 | &fds[alsa_slots], |
| 256 | alsa_nslots, |
| 257 | &alsa_revents)) < 0) |
| 258 | fatal(0, "error calling snd_pcm_poll_descriptors_revents: %d", err); |
| 259 | if(alsa_revents & (POLLOUT | POLLERR)) |
| 260 | return 1; |
| 261 | else |
| 262 | return 0; |
| 263 | } |
| 264 | |
| 265 | const struct speaker_backend alsa_backend = { |
| 266 | BACKEND_ALSA, |
| 267 | 0, |
| 268 | alsa_init, |
| 269 | alsa_activate, |
| 270 | alsa_play, |
| 271 | alsa_deactivate, |
| 272 | alsa_beforepoll, |
| 273 | alsa_ready |
| 274 | }; |
| 275 | |
| 276 | #endif |
| 277 | |
| 278 | /* |
| 279 | Local Variables: |
| 280 | c-basic-offset:2 |
| 281 | comment-column:40 |
| 282 | fill-column:79 |
| 283 | indent-tabs-mode:nil |
| 284 | End: |
| 285 | */ |