Moving mixers to audio outputs

1 files changed, 206 insertions, 0 deletions

diff --git a/src/mixer/alsa_mixer.c b/src/mixer/alsa_mixer.c
new file mode 100644
index 000000000..506daf794
--- /dev/null
+++ b/src/mixer/alsa_mixer.c
@@ -0,0 +1,206 @@
+
+#include "../output_api.h"
+#include "../mixer.h"
+
+#include <glib.h>
+#include <alsa/asoundlib.h>
+
+#define VOLUME_MIXER_ALSA_DEFAULT		"default"
+#define VOLUME_MIXER_ALSA_CONTROL_DEFAULT	"PCM"
+
+struct alsa_mixer {
+	char *device;
+	char *control;
+	snd_mixer_t *handle;
+	snd_mixer_elem_t *elem;
+	long volume_min;
+	long volume_max;
+	int volume_set;
+};
+
+struct alsa_mixer *
+alsa_mixer_init(void)
+{
+	struct alsa_mixer *am = g_malloc(sizeof(struct alsa_mixer));
+	am->device = NULL;
+	am->control = NULL;
+	am->handle = NULL;
+	am->elem = NULL;
+	am->volume_min = 0;
+	am->volume_max = 0;
+	am->volume_set = -1;
+	return am;
+}
+
+void
+alsa_mixer_finish(struct alsa_mixer *am)
+{
+	g_free(am);
+}
+
+void
+alsa_mixer_configure(struct alsa_mixer *am, ConfigParam *param)
+{
+	BlockParam *bp;
+
+	if ((bp = getBlockParam(param, "mix_device")))
+		am->device = bp->value;
+	if ((bp = getBlockParam(param, "mix_control")))
+		am->control = bp->value;
+}
+
+void
+alsa_mixer_close(struct alsa_mixer *am)
+{
+	if (am->handle) snd_mixer_close(am->handle);
+	am->handle = NULL;
+}
+
+bool
+alsa_mixer_open(struct alsa_mixer *am)
+{
+	int err;
+	snd_mixer_elem_t *elem;
+	const char *control_name = VOLUME_MIXER_ALSA_CONTROL_DEFAULT;
+	const char *device = VOLUME_MIXER_ALSA_DEFAULT;
+
+	if (am->device) {
+		device = am->device;
+	}
+	err = snd_mixer_open(&am->handle, 0);
+	snd_config_update_free_global();
+	if (err < 0) {
+		g_warning("problems opening alsa mixer: %s\n", snd_strerror(err));
+		return false;
+	}
+
+	if ((err = snd_mixer_attach(am->handle, device)) < 0) {
+		g_warning("problems attaching alsa mixer: %s\n",
+			snd_strerror(err));
+		alsa_mixer_close(am);
+		return false;
+	}
+
+	if ((err = snd_mixer_selem_register(am->handle, NULL,
+		    NULL)) < 0) {
+		g_warning("problems snd_mixer_selem_register'ing: %s\n",
+			snd_strerror(err));
+		alsa_mixer_close(am);
+		return false;
+	}
+
+	if ((err = snd_mixer_load(am->handle)) < 0) {
+		g_warning("problems snd_mixer_selem_register'ing: %s\n",
+			snd_strerror(err));
+		alsa_mixer_close(am);
+		return false;
+	}
+
+	elem = snd_mixer_first_elem(am->handle);
+
+	if (am->control) {
+		control_name = am->control;
+	}
+
+	while (elem) {
+		if (snd_mixer_elem_get_type(elem) == SND_MIXER_ELEM_SIMPLE) {
+			if (strcasecmp(control_name,
+				       snd_mixer_selem_get_name(elem)) == 0) {
+				break;
+			}
+		}
+		elem = snd_mixer_elem_next(elem);
+	}
+
+	if (elem) {
+		am->elem = elem;
+		snd_mixer_selem_get_playback_volume_range(am->elem,
+							  &am->volume_min,
+							  &am->volume_max);
+		return true;
+	}
+
+	g_warning("can't find alsa mixer control \"%s\"\n", control_name);
+
+	alsa_mixer_close(am);
+	return false;
+}
+
+bool
+alsa_mixer_control(struct alsa_mixer *am, int cmd, void *arg)
+{
+	switch (cmd) {
+	case AC_MIXER_CONFIGURE:
+		alsa_mixer_configure(am, (ConfigParam *)arg);
+		if (am->handle)
+			alsa_mixer_close(am);
+		return true;
+	case AC_MIXER_GETVOL:
+	{
+		int err;
+		int ret, *volume = arg;
+		long level;
+
+		if (!am->handle && !alsa_mixer_open(am)) {
+			return false;
+		}
+		if ((err = snd_mixer_handle_events(am->handle)) < 0) {
+			g_warning("problems getting alsa volume: %s (snd_mixer_%s)\n",
+				snd_strerror(err), "handle_events");
+			alsa_mixer_close(am);
+			return false;
+		}
+		if ((err = snd_mixer_selem_get_playback_volume(am->elem,
+			       SND_MIXER_SCHN_FRONT_LEFT, &level)) < 0) {
+			g_warning("problems getting alsa volume: %s (snd_mixer_%s)\n",
+				snd_strerror(err), "selem_get_playback_volume");
+			alsa_mixer_close(am);
+			return false;
+		}
+		ret = ((am->volume_set / 100.0) * (am->volume_max - am->volume_min)
+			+ am->volume_min) + 0.5;
+		if (am->volume_set > 0 && ret == level) {
+			ret = am->volume_set;
+		} else {
+			ret = (int)(100 * (((float)(level - am->volume_min)) /
+				(am->volume_max - am->volume_min)) + 0.5);
+		}
+		*volume = ret;
+		return true;
+	}
+	case AC_MIXER_SETVOL:
+	{
+		float vol;
+		long level;
+		int *volume = arg;
+		int err;
+
+		if (!am->handle && !alsa_mixer_open(am)) {
+			return false;
+		}
+		vol = *volume;
+
+		am->volume_set = vol + 0.5;
+		am->volume_set = am->volume_set > 100 ? 100 :
+			    (am->volume_set < 0 ? 0 : am->volume_set);
+
+		level = (long)(((vol / 100.0) * (am->volume_max - am->volume_min) +
+			 am->volume_min) + 0.5);
+		level = level > am->volume_max ? am->volume_max : level;
+		level = level < am->volume_min ? am->volume_min : level;
+
+		if ((err = snd_mixer_selem_set_playback_volume_all(am->elem,
+								level)) < 0) {
+			g_warning("problems setting alsa volume: %s\n",
+				snd_strerror(err));
+			alsa_mixer_close(am);
+			return false;
+		}
+		return true;
+	}
+	default:
+		g_warning("Unsuported alsa control\n");
+		break;
+	}
+	return false;
+}