alsaloop: Add OSS mixer redirection support

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

alsaloop/alsaloop.1

@@ -152,6 +152,22 @@ Known attributes:
   iface     - control ID interface
   numid     - control ID numid
 
+.TP
+\fI\-O <ossmixid>\fP | \fI\-\-ossmixer=<midid>\fP
+
+Redirect mixer control from the OSS Mixer emulation layer (capture card)
+to the ALSA layer (capture card). Format of \fIossmixid\fP is
+ALSAID[,INDEX]@OSSID:
+
+  "Master@VOLUME"
+  "PCM,1@ALTPCM"
+
+Known OSS attributes:
+
+  VOLUME, BASS, TREBLE, SYNTH, PCM, SPEAKER, LINE, MIC, CD, IMIX, ALTPCM,
+  RECLEV, IGAIN, OGAIN, LINE1, LINE2, LINE3, DIGITAL1, DIGITAL2, DIGITAL3,
+  PHONEIN, PHONEOUT, VIDEO, RADIO, MONITOR
+
 .TP
 \fI\-v\fP | \fI\-\-verbose\fP
 

alsaloop/alsaloop.c

@@ -164,7 +164,9 @@ void help(void)
 "-a,--slave     stream parameters slave mode (0=auto, 1=on, 2=off)\n"
 "-T,--thread    thread number (-1 = create unique)\n"
 "-m,--mixer	redirect mixer, argument is:\n"
-"			SRC_SLAVE_ID(PLAYBACK)@DST_SLAVE_ID(CAPTURE)\n"
+"		    SRC_SLAVE_ID(PLAYBACK)[@DST_SLAVE_ID(CAPTURE)]\n"
+"-O,--ossmixer	rescan and redirect oss mixer, argument is:\n"
+"		    ALSA_ID@OSS_ID  (for example: \"Master@VOLUME\")\n"
 "-e,--effect    apply an effect (bandpass filter sweep)\n"
 "-v,--verbose   verbose mode (more -v means more verbose)\n"
 );
@@ -266,6 +268,46 @@ static int add_mixers(struct loopback *loop,
 	return 0;
 }
 
+static int add_oss_mixers(struct loopback *loop,
+			  char **mixers,
+			  int mixers_count)
+{
+	struct loopback_ossmixer *mixer, *last = NULL;
+	char *str1, *str2;
+
+	while (mixers_count > 0) {
+		mixer = calloc(1, sizeof(*mixer));
+		if (mixer == NULL)
+			return -ENOMEM;
+		if (last)
+			last->next = mixer;
+		else
+			loop->oss_controls = mixer;
+		last = mixer;
+		str1 = strchr(*mixers, ',');
+		if (str1)
+			*str1 = '\0';
+		str2 = strchr(str1 ? str1 + 1 : *mixers, '@');
+		if (str2)
+			*str2 = '\0';
+		mixer->alsa_id = strdup(*mixers);
+		if (str1)
+			mixer->alsa_index = atoi(str1);
+		mixer->oss_id = strdup(str2 ? str2 + 1 : *mixers);
+		if (mixer->alsa_id == NULL || mixer->oss_id == NULL) {
+			logit(LOG_CRIT, "Not enough memory");
+			return -ENOMEM;
+		}
+		if (str1)
+			*str1 = ',';
+		if (str2)
+			*str2 = ',';
+		mixers++;
+		mixers_count--;
+	}
+	return 0;
+}
+
 static int parse_config_file(const char *file, snd_output_t *output);
 
 static int parse_config(int argc, char *argv[], snd_output_t *output)
@@ -294,6 +336,7 @@ static int parse_config(int argc, char *argv[], snd_output_t *output)
 		{"slave", 1, NULL, 'a'},
 		{"thread", 1, NULL, 'T'},
 		{"mixer", 1, NULL, 'm'},
+		{"ossmixer", 1, NULL, 'O'},
 		{NULL, 0, NULL, 0},
 	};
 	int err, morehelp;
@@ -318,11 +361,15 @@ static int parse_config(int argc, char *argv[], snd_output_t *output)
 	struct loopback *loop = NULL;
 	char *arg_mixers[MAX_MIXERS];
 	int arg_mixers_count = 0;
+	char *arg_ossmixers[MAX_MIXERS];
+	int arg_ossmixers_count = 0;
 
 	morehelp = 0;
 	while (1) {
 		int c;
-		if ((c = getopt_long(argc, argv, "hdg:P:C:l:t:F:f:c:r:s:benvA:S:a:m:T:", long_option, NULL)) < 0)
+		if ((c = getopt_long(argc, argv,
+				"hdg:P:C:l:t:F:f:c:r:s:benvA:S:a:m:T:O:",
+				long_option, NULL)) < 0)
 			break;
 		switch (c) {
 		case 'h':
@@ -445,6 +492,13 @@ static int parse_config(int argc, char *argv[], snd_output_t *output)
 			}
 			arg_mixers[arg_mixers_count++] = optarg;
 			break;
+		case 'O':
+			if (arg_ossmixers_count >= MAX_MIXERS) {
+				logit(LOG_CRIT, "Maximum redirected mixer controls reached (max %i)\n", (int)MAX_MIXERS);
+				exit(EXIT_FAILURE);
+			}
+			arg_ossmixers[arg_ossmixers_count++] = optarg;
+			break;
 		case 'v':
 			verbose++;
 			break;
@@ -490,6 +544,11 @@ static int parse_config(int argc, char *argv[], snd_output_t *output)
 			logit(LOG_CRIT, "Unable to add mixer controls.\n");
 			exit(EXIT_FAILURE);
 		}
+		err = add_oss_mixers(loop, arg_ossmixers, arg_ossmixers_count);
+		if (err < 0) {
+			logit(LOG_CRIT, "Unable to add ossmixer controls.\n");
+			exit(EXIT_FAILURE);
+		}
 #ifdef USE_SAMPLERATE
 		loop->src_enable = arg_samplerate > 0;
 		if (loop->src_enable)

alsaloop/alsaloop.h

@@ -71,10 +71,19 @@ struct loopback_mixer {
 	struct loopback_mixer *next;
 };
 
+struct loopback_ossmixer {
+	unsigned int skip:1;
+	const char *alsa_id;
+	int alsa_index;
+	const char *oss_id;
+	struct loopback_ossmixer *next;
+};
+
 struct loopback_handle {
 	struct loopback *loopback;
 	char *device;
 	char *id;
+	int card_number;
 	snd_pcm_t *handle;
 	snd_pcm_access_t access;
 	snd_pcm_format_t format;
@@ -143,6 +152,7 @@ struct loopback {
 	snd_timestamp_t tstamp_end;
 	/* control mixer */
 	struct loopback_mixer *controls;
+	struct loopback_ossmixer *oss_controls;
 	/* sample rate */
 	unsigned int use_samplerate:1;
 #ifdef USE_SAMPLERATE

alsaloop/control.c

@@ -205,6 +205,34 @@ static int copy_value(struct loopback_control *dst,
 	return 0;
 }
 
+static int oss_set(struct loopback *loop,
+		   struct loopback_ossmixer *ossmix,
+		   int enable)
+{
+	char buf[128], file[128];
+	int fd;
+
+	if (loop->capt->card_number < 0)
+		return 0;
+	if (!enable) {
+		sprintf(buf, "%s \"\" 0\n", ossmix->oss_id);
+	} else {
+		sprintf(buf, "%s \"%s\" %i\n", ossmix->oss_id, ossmix->alsa_id, ossmix->alsa_index);
+	}
+	sprintf(file, "/proc/asound/card%i/oss_mixer", loop->capt->card_number);
+	if (verbose)
+		snd_output_printf(loop->output, "%s: Initialize OSS volume %s: %s", loop->id, file, buf);
+	fd = open(file, O_WRONLY);
+	if (fd >= 0 && write(fd, buf, strlen(buf)) == strlen(buf)) {
+		close(fd);
+		return 0;
+	}
+	if (fd >= 0)
+		close(fd);
+	logit(LOG_INFO, "%s: Unable to initialize OSS Mixer ID '%s'\n", loop->id, ossmix->oss_id);
+	return -1;
+}
+
 static int control_init2(struct loopback *loop,
 			 struct loopback_mixer *mix)
 {
@@ -280,12 +308,15 @@ static int control_init2(struct loopback *loop,
 int control_init(struct loopback *loop)
 {
 	struct loopback_mixer *mix;
+	struct loopback_ossmixer *ossmix;
 	int err;
 
+	for (ossmix = loop->oss_controls; ossmix; ossmix = ossmix->next)
+		oss_set(loop, ossmix, 0);
 	for (mix = loop->controls; mix; mix = mix->next) {
 		err = control_init1(loop->play, &mix->src);
 		if (err < 0) {
-			logit(LOG_WARNING, "Disabling playback control '%s'\n", id_str(mix->src.id));
+			logit(LOG_WARNING, "%s: Disabling playback control '%s'\n", loop->id, id_str(mix->src.id));
 			mix->skip = 1;
 			continue;
 		}
@@ -293,22 +324,35 @@ int control_init(struct loopback *loop)
 		if (err < 0)
 			return err;
 	}
+	for (ossmix = loop->oss_controls; ossmix; ossmix = ossmix->next) {
+		err = oss_set(loop, ossmix, 1);
+		if (err < 0) {
+			ossmix->skip = 1;
+			logit(LOG_WARNING, "%s: Disabling OSS mixer ID '%s'\n", loop->id, ossmix->oss_id);
+		}
+	}
 	return 0;
 }
 
 int control_done(struct loopback *loop)
 {
 	struct loopback_mixer *mix;
+	struct loopback_ossmixer *ossmix;
 	int err;
 
 	if (loop->capt->ctl == NULL)
 		return 0;
+	for (ossmix = loop->oss_controls; ossmix; ossmix = ossmix->next) {
+		err = oss_set(loop, ossmix, 0);
+		if (err < 0)
+			logit(LOG_WARNING, "%s: Unable to remove OSS control '%s'\n", loop->id, ossmix->oss_id);
+	}
 	for (mix = loop->controls; mix; mix = mix->next) {
 		if (mix->skip)
 			continue;
 		err = snd_ctl_elem_remove(loop->capt->ctl, mix->dst.id);
 		if (err < 0)
-			logit(LOG_WARNING, "Unable to remove control '%s': %s\n", id_str(mix->dst.id), snd_strerror(err));
+			logit(LOG_WARNING, "%s: Unable to remove control '%s': %s\n", loop->id, id_str(mix->dst.id), snd_strerror(err));
 	}
 	return 0;
 }

alsaloop/pcmjob.c

@@ -1022,6 +1022,7 @@ static int openit(struct loopback_handle *lhandle)
 	device = snd_pcm_info_get_device(info);
 	subdevice = snd_pcm_info_get_subdevice(info);
 	snd_pcm_info_free(info);
+	lhandle->card_number = card;
 	lhandle->ctl = NULL;
 	if (card >= 0) {
 		char name[16];

alsaloop/test.sh

@@ -10,7 +10,9 @@ test1() {
     --tlatency 50000 \
     --mixer "name='Master Playback Volume'@name='Master Playback Volume'" \
     --mixer "name='Master Playback Switch'@name='Master Playback Switch'" \
-    --mixer "name='PCM Playback Volume'"
+    --mixer "name='PCM Playback Volume'" \
+    --ossmixer "Master@VOLUME" \
+    --ossmixer "PCM@PCM"
 }
 
 test2() {