make the feederchain builder work for recording. this has not been tested

extensively as none of my testboxes have speakers or an audio source at
present, but the chains built look correct and reading /dev/audio (ulaw,
translated from signed 16 bit little-endian) gives values within the
expected range for silence.

sys/dev/sound/pcm/channel.c

@@ -997,7 +997,7 @@ chn_buildfeeder(struct pcm_channel *c)
 {
 	struct feeder_class *fc;
 	struct pcm_feederdesc desc;
-	u_int32_t tmp[2], type, flags;
+	u_int32_t tmp[2], type, flags, hwfmt;
 
 	CHN_LOCKASSERT(c);
 	while (chn_removefeeder(c) == 0);
@@ -1072,14 +1072,22 @@ chn_buildfeeder(struct pcm_channel *c)
 		}
 	}
 
-	if (!fmtvalid(c->feeder->desc->out, chn_getcaps(c)->fmtlist)) {
-		if (chn_fmtchain(c, chn_getcaps(c)->fmtlist) == 0) {
-			DEB(printf("can't build fmtchain from %x\n", c->feeder->desc->out));
-			return EINVAL;
+	if (fmtvalid(c->feeder->desc->out, chn_getcaps(c)->fmtlist)) {
+		hwfmt = c->feeder->desc->out;
+	} else {
+		if (c->direction == PCMDIR_REC) {
+			tmp[0] = c->format;
+			tmp[1] = NULL;
+			hwfmt = chn_fmtchain(c, tmp);
+		} else {
+			hwfmt = chn_fmtchain(c, chn_getcaps(c)->fmtlist);
 		}
-		DEB(printf("built fmtchain from %x\n", c->feeder->desc->out));
 	}
 
+	if (hwfmt == 0)
+		return EINVAL;
+
+	sndbuf_setfmt(c->bufhard, hwfmt);
 	return 0;
 }
 

sys/dev/sound/pcm/feeder.c

@@ -267,25 +267,60 @@ feeder_fmtchain(u_int32_t *to, struct pcm_feeder *source, struct pcm_feeder *sto
 u_int32_t
 chn_fmtchain(struct pcm_channel *c, u_int32_t *to)
 {
-	struct pcm_feeder *try, *stop;
-	int max;
+	struct pcm_feeder *try, *del, *stop;
+	u_int32_t tmpfrom[2], best, *from;
+	int i, max, bestmax;
+
+	KASSERT(c != NULL, ("c == NULL"));
+	KASSERT(c->feeder != NULL, ("c->feeder == NULL"));
+	KASSERT(to != NULL, ("to == NULL"));
+	KASSERT(to[0] != 0, ("to[0] == 0"));
 
-	/* we're broken for recording currently, reject attempts */
-	if (c->direction == PCMDIR_REC)
-		return EINVAL;
 	stop = c->feeder;
-	try = NULL;
-	max = 0;
-	while (try == NULL && max < 8) {
-		try = feeder_fmtchain(to, c->feeder, stop, max);
-		max++;
+
+	if (c->direction == PCMDIR_REC && c->feeder->desc->type == FEEDER_ROOT) {
+		from = chn_getcaps(c)->fmtlist;
+	} else {
+		tmpfrom[0] = c->feeder->desc->out;
+		tmpfrom[1] = 0;
+		from = tmpfrom;
 	}
+
+	i = 0;
+	best = 0;
+	bestmax = 100;
+	while (from[i] != 0) {
+		c->feeder->desc->out = from[i];
+		try = NULL;
+		max = 0;
+		while (try == NULL && max < 8) {
+			try = feeder_fmtchain(to, c->feeder, stop, max);
+			if (try == NULL)
+				max++;
+		}
+		if (try != NULL && max < bestmax) {
+			bestmax = max;
+			best = from[i];
+		}
+		while (try != NULL && try != stop) {
+			del = try;
+			try = try->source;
+			feeder_destroy(del);
+		}
+		i++;
+	}
+	if (best == 0)
+		return 0;
+
+	c->feeder->desc->out = best;
+	try = feeder_fmtchain(to, c->feeder, stop, bestmax);
 	if (try == NULL)
 		return 0;
+
 	c->feeder = try;
 	c->align = 0;
 #ifdef FEEDER_DEBUG
-	printf("chain: ");
+	printf("\n\nchain: ");
 #endif
 	while (try && (try != stop)) {
 #ifdef FEEDER_DEBUG
@@ -293,6 +328,8 @@ chn_fmtchain(struct pcm_channel *c, u_int32_t *to)
 		if (try->source)
 			printf(" -> ");
 #endif
+		if (try->source)
+			try->source->parent = try;
 		if (try->align > 0)
 			c->align += try->align;
 		else if (try->align < 0 && c->align < -try->align)
@@ -302,7 +339,7 @@ chn_fmtchain(struct pcm_channel *c, u_int32_t *to)
 #ifdef FEEDER_DEBUG
 	printf("%s [%d]\n", try->class->name, try->desc->idx);
 #endif
-	return c->feeder->desc->out;
+	return (c->direction == PCMDIR_REC)? best : c->feeder->desc->out;
 }
 
 /*****************************************************************************/

sys/dev/sound/pcm/feeder.h

@@ -46,7 +46,7 @@ struct pcm_feeder {
 	struct pcm_feederdesc *desc;
 	void *data;
 	struct feeder_class *class;
-	struct pcm_feeder *source;
+	struct pcm_feeder *source, *parent;
 };
 
 void feeder_register(void *p);