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 3 of the License, or
8 * (at your option) any later version.
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.
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/>.
18 /** @file server/speaker-alsa.c
19 * @brief Support for @ref BACKEND_ALSA */
23 #if HAVE_ALSA_ASOUNDLIB_H
27 #include <alsa/asoundlib.h>
29 #include "configuration.h"
32 #include "speaker-protocol.h"
35 /** @brief The current PCM handle */
36 static snd_pcm_t
*pcm
;
38 /** @brief Last seen buffer size */
39 static snd_pcm_uframes_t last_pcm_bufsize
;
41 /** @brief ALSA backend initialization */
42 static void alsa_init(void) {
43 info("selected ALSA backend");
46 /** @brief Log ALSA parameters */
47 static void log_params(snd_pcm_hw_params_t
*hwparams
,
48 snd_pcm_sw_params_t
*swparams
) {
51 return; /* too verbose */
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
64 snd_pcm_sw_params_get_sleep_min(swparams
, &u
);
65 info("sw sleep_min=%lu", (unsigned long)u
);
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
);
79 /** @brief ALSA deactivation */
80 static void alsa_deactivate(void) {
84 if((err
= snd_pcm_nonblock(pcm
, 0)) < 0)
85 fatal(0, "error calling snd_pcm_nonblock: %d", err
);
91 device_state
= device_closed
;
92 D(("released audio device"));
96 /** @brief ALSA backend activation */
97 static void alsa_activate(void) {
99 snd_pcm_hw_params_t
*hwparams
;
100 snd_pcm_sw_params_t
*swparams
;
101 snd_pcm_uframes_t pcm_bufsize
;
103 int sample_format
= 0;
107 if((err
= snd_pcm_open(&pcm
,
109 SND_PCM_STREAM_PLAYBACK
,
110 SND_PCM_NONBLOCK
))) {
111 error(0, "error from snd_pcm_open: %d", err
);
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
) {
123 sample_format
= SND_PCM_FORMAT_S8
;
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;
130 error(0, "unrecognized byte format %d", config
->sample_format
.endian
);
135 error(0, "unsupported sample size %d", config
->sample_format
.bits
);
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",
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
);
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
);
158 pcm_bufsize
= 3 * FRAMES
;
159 if((err
= snd_pcm_hw_params_set_buffer_size_near(pcm
, hwparams
,
161 fatal(0, "error from snd_pcm_hw_params_set_buffer_size (%d): %d",
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",
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
;
186 /* We assume the error is temporary and that we'll retry in a bit. */
190 device_state
= device_error
;
195 /** @brief Play via ALSA */
196 static size_t alsa_play(size_t frames
) {
197 snd_pcm_sframes_t pcm_written_frames
;
200 pcm_written_frames
= snd_pcm_writei(pcm
,
201 playing
->buffer
+ playing
->start
,
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
);
215 fatal(0, "error calling snd_pcm_writei: %d",
216 (int)pcm_written_frames
);
219 return pcm_written_frames
;
222 static int alsa_slots
, alsa_nslots
= -1;
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
234 alsa_nslots
= snd_pcm_poll_descriptors(pcm
, &fds
[fdno
], NFDS
- fdno
);
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
);
243 } while(retry
-- > 0);
248 /** @brief Process poll() results for ALSA */
249 static int alsa_ready(void) {
252 unsigned short alsa_revents
;
254 if((err
= snd_pcm_poll_descriptors_revents(pcm
,
258 fatal(0, "error calling snd_pcm_poll_descriptors_revents: %d", err
);
259 if(alsa_revents
& (POLLOUT
| POLLERR
))
265 const struct speaker_backend alsa_backend
= {