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b25aac59 | 1 | /* |
2 | * This file is part of DisOrder | |
5aff007d | 3 | * Copyright (C) 2007, 2008 Richard Kettlewell |
b25aac59 | 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 | ||
05b75f8d | 32 | #include "common.h" |
b25aac59 | 33 | |
34 | #if HAVE_ALSA_ASOUNDLIB_H | |
35 | ||
b25aac59 | 36 | #include <fcntl.h> |
37 | #include <unistd.h> | |
b25aac59 | 38 | #include <errno.h> |
39 | #include <stddef.h> | |
40 | #include <ctype.h> | |
41 | #include <sys/ioctl.h> | |
42 | #include <alsa/asoundlib.h> | |
43 | ||
44 | #include "configuration.h" | |
45 | #include "mixer.h" | |
46 | #include "log.h" | |
47 | #include "syscalls.h" | |
48 | ||
49 | /** @brief Shared state for ALSA mixer support */ | |
50 | struct alsa_mixer_state { | |
51 | /** @brief Mixer handle */ | |
52 | snd_mixer_t *handle; | |
53 | ||
54 | /** @brief Mixer control */ | |
55 | snd_mixer_elem_t *elem; | |
56 | ||
57 | /** @brief Left channel */ | |
58 | snd_mixer_selem_channel_id_t left; | |
59 | ||
60 | /** @brief Right channel */ | |
61 | snd_mixer_selem_channel_id_t right; | |
62 | ||
63 | /** @brief Minimum level */ | |
64 | long min; | |
65 | ||
66 | /** @brief Maximum level */ | |
67 | long max; | |
68 | }; | |
69 | ||
70 | /** @brief Destroy a @ref alsa_mixer_state */ | |
71 | static void alsa_close(struct alsa_mixer_state *h) { | |
72 | /* TODO h->elem */ | |
73 | if(h->handle) | |
74 | snd_mixer_close(h->handle); | |
75 | } | |
76 | ||
77 | /** @brief Initialize a @ref alsa_mixer_state */ | |
78 | static int alsa_open(struct alsa_mixer_state *h) { | |
79 | int err; | |
80 | snd_mixer_selem_id_t *id; | |
81 | ||
82 | snd_mixer_selem_id_alloca(&id); | |
83 | memset(h, 0, sizeof h); | |
84 | if((err = snd_mixer_open(&h->handle, 0))) { | |
85 | error(0, "snd_mixer_open: %s", snd_strerror(err)); | |
86 | return -1; | |
87 | } | |
88 | if((err = snd_mixer_attach(h->handle, config->device))) { | |
89 | error(0, "snd_mixer_attach %s: %s", | |
90 | config->device, snd_strerror(err)); | |
91 | goto error; | |
92 | } | |
93 | if((err = snd_mixer_selem_register(h->handle, 0/*options*/, 0/*classp*/))) { | |
94 | error(0, "snd_mixer_selem_register %s: %s", | |
95 | config->device, snd_strerror(err)); | |
96 | goto error; | |
97 | } | |
98 | if((err = snd_mixer_load(h->handle))) { | |
99 | error(0, "snd_mixer_load %s: %s", | |
100 | config->device, snd_strerror(err)); | |
101 | goto error; | |
102 | } | |
103 | snd_mixer_selem_id_set_name(id, config->channel); | |
104 | snd_mixer_selem_id_set_index(id, atoi(config->mixer)); | |
105 | if(!(h->elem = snd_mixer_find_selem(h->handle, id))) { | |
8899ace0 RK |
106 | error(0, "device '%s' mixer control '%s,%s' does not exist", |
107 | config->device, config->channel, config->mixer); | |
b25aac59 | 108 | goto error; |
109 | } | |
110 | if(!snd_mixer_selem_has_playback_volume(h->elem)) { | |
8899ace0 RK |
111 | error(0, "device '%s' mixer control '%s,%s' has no playback volume", |
112 | config->device, config->channel, config->mixer); | |
b25aac59 | 113 | goto error; |
114 | } | |
115 | if(snd_mixer_selem_is_playback_mono(h->elem)) { | |
116 | h->left = h->right = SND_MIXER_SCHN_MONO; | |
117 | } else { | |
118 | h->left = SND_MIXER_SCHN_FRONT_LEFT; | |
119 | h->right = SND_MIXER_SCHN_FRONT_RIGHT; | |
120 | } | |
121 | if(!snd_mixer_selem_has_playback_channel(h->elem, h->left) | |
122 | || !snd_mixer_selem_has_playback_channel(h->elem, h->right)) { | |
8899ace0 RK |
123 | error(0, "device '%s' mixer control '%s,%s' lacks required playback channels", |
124 | config->device, config->channel, config->mixer); | |
b25aac59 | 125 | goto error; |
126 | } | |
127 | snd_mixer_selem_get_playback_volume_range(h->elem, &h->min, &h->max); | |
128 | return 0; | |
129 | error: | |
130 | alsa_close(h); | |
131 | return -1; | |
132 | } | |
133 | ||
134 | /** @brief Convert a level to a percentage */ | |
135 | static int to_percent(const struct alsa_mixer_state *h, long n) { | |
136 | return (n - h->min) * 100 / (h->max - h->min); | |
137 | } | |
138 | ||
139 | /** @brief Get ALSA volume */ | |
140 | static int alsa_get(int *left, int *right) { | |
141 | struct alsa_mixer_state h[1]; | |
142 | long l, r; | |
143 | int err; | |
144 | ||
145 | if(alsa_open(h)) | |
146 | return -1; | |
147 | if((err = snd_mixer_selem_get_playback_volume(h->elem, h->left, &l)) | |
148 | || (err = snd_mixer_selem_get_playback_volume(h->elem, h->right, &r))) { | |
149 | error(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err)); | |
150 | goto error; | |
151 | } | |
152 | *left = to_percent(h, l); | |
153 | *right = to_percent(h, r); | |
154 | alsa_close(h); | |
155 | return 0; | |
156 | error: | |
157 | alsa_close(h); | |
158 | return -1; | |
159 | } | |
160 | ||
161 | /** @brief Convert a percentage to a level */ | |
162 | static int from_percent(const struct alsa_mixer_state *h, int n) { | |
163 | return h->min + n * (h->max - h->min) / 100; | |
164 | } | |
165 | ||
166 | /** @brief Set ALSA volume */ | |
167 | static int alsa_set(int *left, int *right) { | |
168 | struct alsa_mixer_state h[1]; | |
169 | long l, r; | |
170 | int err; | |
171 | ||
172 | if(alsa_open(h)) | |
173 | return -1; | |
174 | /* Set the volume */ | |
175 | if(h->left == h->right) { | |
176 | /* Mono output - just use the loudest */ | |
177 | if((err = snd_mixer_selem_set_playback_volume | |
178 | (h->elem, h->left, | |
179 | from_percent(h, *left > *right ? *left : *right)))) { | |
180 | error(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err)); | |
181 | goto error; | |
182 | } | |
183 | } else { | |
184 | /* Stereo output */ | |
185 | if((err = snd_mixer_selem_set_playback_volume | |
186 | (h->elem, h->left, from_percent(h, *left))) | |
187 | || (err = snd_mixer_selem_set_playback_volume | |
188 | (h->elem, h->right, from_percent(h, *right)))) { | |
189 | error(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err)); | |
190 | goto error; | |
191 | } | |
192 | } | |
193 | /* Read it back to see what we ended up at */ | |
194 | if((err = snd_mixer_selem_get_playback_volume(h->elem, h->left, &l)) | |
195 | || (err = snd_mixer_selem_get_playback_volume(h->elem, h->right, &r))) { | |
196 | error(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err)); | |
197 | goto error; | |
198 | } | |
199 | *left = to_percent(h, l); | |
200 | *right = to_percent(h, r); | |
201 | alsa_close(h); | |
202 | return 0; | |
203 | error: | |
204 | alsa_close(h); | |
205 | return -1; | |
206 | } | |
207 | ||
208 | /** @brief ALSA mixer vtable */ | |
209 | const struct mixer mixer_alsa = { | |
210 | BACKEND_ALSA, | |
211 | alsa_get, | |
212 | alsa_set, | |
213 | "0", | |
214 | "PCM" | |
215 | }; | |
216 | #endif | |
217 | ||
218 | /* | |
219 | Local Variables: | |
220 | c-basic-offset:2 | |
221 | comment-column:40 | |
222 | End: | |
223 | */ |