Commit | Line | Data |
---|---|---|
b25aac59 | 1 | /* |
2 | * This file is part of DisOrder | |
3 | * Copyright (C) 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 lib/mixer-alsa.c | |
21 | * @brief ALSA mixer support | |
22 | * | |
23 | * The documentation for ALSA's mixer support is completely hopeless, | |
24 | * which is a particular nuisnace given it's got an incredibly verbose | |
25 | * API. Much of this code is cribbed from | |
26 | * alsa-utils-1.0.13/amixer/amixer.c. | |
27 | * | |
28 | * Mono output devices are supported, but the support is not tested | |
29 | * (as I don't one). | |
30 | */ | |
31 | ||
32 | #include <config.h> | |
33 | ||
34 | #if HAVE_ALSA_ASOUNDLIB_H | |
35 | ||
36 | #include "types.h" | |
37 | ||
38 | #include <stdio.h> | |
39 | #include <string.h> | |
40 | #include <fcntl.h> | |
41 | #include <unistd.h> | |
42 | #include <stdlib.h> | |
43 | #include <errno.h> | |
44 | #include <stddef.h> | |
45 | #include <ctype.h> | |
46 | #include <sys/ioctl.h> | |
47 | #include <alsa/asoundlib.h> | |
48 | ||
49 | #include "configuration.h" | |
50 | #include "mixer.h" | |
51 | #include "log.h" | |
52 | #include "syscalls.h" | |
53 | ||
54 | /** @brief Shared state for ALSA mixer support */ | |
55 | struct alsa_mixer_state { | |
56 | /** @brief Mixer handle */ | |
57 | snd_mixer_t *handle; | |
58 | ||
59 | /** @brief Mixer control */ | |
60 | snd_mixer_elem_t *elem; | |
61 | ||
62 | /** @brief Left channel */ | |
63 | snd_mixer_selem_channel_id_t left; | |
64 | ||
65 | /** @brief Right channel */ | |
66 | snd_mixer_selem_channel_id_t right; | |
67 | ||
68 | /** @brief Minimum level */ | |
69 | long min; | |
70 | ||
71 | /** @brief Maximum level */ | |
72 | long max; | |
73 | }; | |
74 | ||
75 | /** @brief Destroy a @ref alsa_mixer_state */ | |
76 | static void alsa_close(struct alsa_mixer_state *h) { | |
77 | /* TODO h->elem */ | |
78 | if(h->handle) | |
79 | snd_mixer_close(h->handle); | |
80 | } | |
81 | ||
82 | /** @brief Initialize a @ref alsa_mixer_state */ | |
83 | static int alsa_open(struct alsa_mixer_state *h) { | |
84 | int err; | |
85 | snd_mixer_selem_id_t *id; | |
86 | ||
87 | snd_mixer_selem_id_alloca(&id); | |
88 | memset(h, 0, sizeof h); | |
89 | if((err = snd_mixer_open(&h->handle, 0))) { | |
90 | error(0, "snd_mixer_open: %s", snd_strerror(err)); | |
91 | return -1; | |
92 | } | |
93 | if((err = snd_mixer_attach(h->handle, config->device))) { | |
94 | error(0, "snd_mixer_attach %s: %s", | |
95 | config->device, snd_strerror(err)); | |
96 | goto error; | |
97 | } | |
98 | if((err = snd_mixer_selem_register(h->handle, 0/*options*/, 0/*classp*/))) { | |
99 | error(0, "snd_mixer_selem_register %s: %s", | |
100 | config->device, snd_strerror(err)); | |
101 | goto error; | |
102 | } | |
103 | if((err = snd_mixer_load(h->handle))) { | |
104 | error(0, "snd_mixer_load %s: %s", | |
105 | config->device, snd_strerror(err)); | |
106 | goto error; | |
107 | } | |
108 | snd_mixer_selem_id_set_name(id, config->channel); | |
109 | snd_mixer_selem_id_set_index(id, atoi(config->mixer)); | |
110 | if(!(h->elem = snd_mixer_find_selem(h->handle, id))) { | |
8899ace0 RK |
111 | error(0, "device '%s' mixer control '%s,%s' does not exist", |
112 | config->device, config->channel, config->mixer); | |
b25aac59 | 113 | goto error; |
114 | } | |
115 | if(!snd_mixer_selem_has_playback_volume(h->elem)) { | |
8899ace0 RK |
116 | error(0, "device '%s' mixer control '%s,%s' has no playback volume", |
117 | config->device, config->channel, config->mixer); | |
b25aac59 | 118 | goto error; |
119 | } | |
120 | if(snd_mixer_selem_is_playback_mono(h->elem)) { | |
121 | h->left = h->right = SND_MIXER_SCHN_MONO; | |
122 | } else { | |
123 | h->left = SND_MIXER_SCHN_FRONT_LEFT; | |
124 | h->right = SND_MIXER_SCHN_FRONT_RIGHT; | |
125 | } | |
126 | if(!snd_mixer_selem_has_playback_channel(h->elem, h->left) | |
127 | || !snd_mixer_selem_has_playback_channel(h->elem, h->right)) { | |
8899ace0 RK |
128 | error(0, "device '%s' mixer control '%s,%s' lacks required playback channels", |
129 | config->device, config->channel, config->mixer); | |
b25aac59 | 130 | goto error; |
131 | } | |
132 | snd_mixer_selem_get_playback_volume_range(h->elem, &h->min, &h->max); | |
133 | return 0; | |
134 | error: | |
135 | alsa_close(h); | |
136 | return -1; | |
137 | } | |
138 | ||
139 | /** @brief Convert a level to a percentage */ | |
140 | static int to_percent(const struct alsa_mixer_state *h, long n) { | |
141 | return (n - h->min) * 100 / (h->max - h->min); | |
142 | } | |
143 | ||
144 | /** @brief Get ALSA volume */ | |
145 | static int alsa_get(int *left, int *right) { | |
146 | struct alsa_mixer_state h[1]; | |
147 | long l, r; | |
148 | int err; | |
149 | ||
150 | if(alsa_open(h)) | |
151 | return -1; | |
152 | if((err = snd_mixer_selem_get_playback_volume(h->elem, h->left, &l)) | |
153 | || (err = snd_mixer_selem_get_playback_volume(h->elem, h->right, &r))) { | |
154 | error(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err)); | |
155 | goto error; | |
156 | } | |
157 | *left = to_percent(h, l); | |
158 | *right = to_percent(h, r); | |
159 | alsa_close(h); | |
160 | return 0; | |
161 | error: | |
162 | alsa_close(h); | |
163 | return -1; | |
164 | } | |
165 | ||
166 | /** @brief Convert a percentage to a level */ | |
167 | static int from_percent(const struct alsa_mixer_state *h, int n) { | |
168 | return h->min + n * (h->max - h->min) / 100; | |
169 | } | |
170 | ||
171 | /** @brief Set ALSA volume */ | |
172 | static int alsa_set(int *left, int *right) { | |
173 | struct alsa_mixer_state h[1]; | |
174 | long l, r; | |
175 | int err; | |
176 | ||
177 | if(alsa_open(h)) | |
178 | return -1; | |
179 | /* Set the volume */ | |
180 | if(h->left == h->right) { | |
181 | /* Mono output - just use the loudest */ | |
182 | if((err = snd_mixer_selem_set_playback_volume | |
183 | (h->elem, h->left, | |
184 | from_percent(h, *left > *right ? *left : *right)))) { | |
185 | error(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err)); | |
186 | goto error; | |
187 | } | |
188 | } else { | |
189 | /* Stereo output */ | |
190 | if((err = snd_mixer_selem_set_playback_volume | |
191 | (h->elem, h->left, from_percent(h, *left))) | |
192 | || (err = snd_mixer_selem_set_playback_volume | |
193 | (h->elem, h->right, from_percent(h, *right)))) { | |
194 | error(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err)); | |
195 | goto error; | |
196 | } | |
197 | } | |
198 | /* Read it back to see what we ended up at */ | |
199 | if((err = snd_mixer_selem_get_playback_volume(h->elem, h->left, &l)) | |
200 | || (err = snd_mixer_selem_get_playback_volume(h->elem, h->right, &r))) { | |
201 | error(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err)); | |
202 | goto error; | |
203 | } | |
204 | *left = to_percent(h, l); | |
205 | *right = to_percent(h, r); | |
206 | alsa_close(h); | |
207 | return 0; | |
208 | error: | |
209 | alsa_close(h); | |
210 | return -1; | |
211 | } | |
212 | ||
213 | /** @brief ALSA mixer vtable */ | |
214 | const struct mixer mixer_alsa = { | |
215 | BACKEND_ALSA, | |
216 | alsa_get, | |
217 | alsa_set, | |
218 | "0", | |
219 | "PCM" | |
220 | }; | |
221 | #endif | |
222 | ||
223 | /* | |
224 | Local Variables: | |
225 | c-basic-offset:2 | |
226 | comment-column:40 | |
227 | End: | |
228 | */ |