[stage: 4/9]

- Rearrange FEEDER_* constants starting from 0 to 31, so the future
  additions will be much easier and consistent.
- Introduce FEEDER_SWAPLR. Few super broken hardwares (found on several
  extremely cheap uaudio stick, possibly others) mistakenly wired left
  and right channels wrongly, screwing output or input.

sys/dev/sound/pcm/channel.c

@@ -1795,7 +1795,7 @@ chn_buildfeeder(struct pcm_channel *c)
 
 	DEB(printf("feederflags %x\n", flags));
 
-	for (type = FEEDER_RATE; type <= FEEDER_LAST; type++) {
+	for (type = FEEDER_RATE; type < FEEDER_LAST; type++) {
 		if (flags & (1 << type)) {
 			desc.type = type;
 			desc.in = 0;

sys/dev/sound/pcm/feeder.c

@@ -37,8 +37,40 @@ MALLOC_DEFINE(M_FEEDER, "feeder", "pcm feeder");
 
 int feeder_buffersize = FEEDBUFSZ;
 TUNABLE_INT("hw.snd.feeder_buffersize", &feeder_buffersize);
+
+#ifdef SND_DEBUG
+static int
+sysctl_hw_snd_feeder_buffersize(SYSCTL_HANDLER_ARGS)
+{
+	int i, err, val;
+
+	val = feeder_buffersize;
+	err = sysctl_handle_int(oidp, &val, sizeof(val), req);
+
+	if (err != 0 || req->newptr == NULL)
+		return err;
+
+	if (val < FEEDBUFSZ_MIN || val > FEEDBUFSZ_MAX)
+		return EINVAL;
+
+	i = 0;
+	while (val >> i)
+		i++;
+	i = 1 << i;
+	if (i > val && (i >> 1) > 0 && (i >> 1) >= ((val * 3) >> 2))
+		i >>= 1;
+
+	feeder_buffersize = i;
+
+	return err;
+}
+SYSCTL_PROC(_hw_snd, OID_AUTO, feeder_buffersize, CTLTYPE_INT | CTLFLAG_RW,
+	0, sizeof(int), sysctl_hw_snd_feeder_buffersize, "I",
+	"feeder buffer size");
+#else
 SYSCTL_INT(_hw_snd, OID_AUTO, feeder_buffersize, CTLFLAG_RD,
 	&feeder_buffersize, FEEDBUFSZ, "feeder buffer size");
+#endif
 
 struct feedertab_entry {
 	SLIST_ENTRY(feedertab_entry) link;
@@ -824,10 +856,9 @@ feed_root(struct pcm_feeder *feeder, struct pcm_channel *ch, u_int8_t *buffer, u
 			    offset, count, l, ch->feedcount);
 
 		if (ch->feedcount == 1) {
-			if (offset > 0)
-				memset(buffer,
-				    sndbuf_zerodata(sndbuf_getfmt(src)),
-				    offset);
+			memset(buffer,
+			    sndbuf_zerodata(sndbuf_getfmt(src)),
+			    offset);
 			if (l > 0)
 				sndbuf_dispose(src, buffer + offset, l);
 			else
@@ -835,34 +866,32 @@ feed_root(struct pcm_feeder *feeder, struct pcm_channel *ch, u_int8_t *buffer, u
 		} else {
 			if (l > 0)
 				sndbuf_dispose(src, buffer, l);
-			if (offset > 0) {
 #if 1
+			memset(buffer + l,
+			    sndbuf_zerodata(sndbuf_getfmt(src)),
+			    offset);
+			if (!(ch->flags & CHN_F_CLOSING))
+				ch->xruns++;
+#else
+			if (l < 1 || (ch->flags & CHN_F_CLOSING)) {
 				memset(buffer + l,
 				    sndbuf_zerodata(sndbuf_getfmt(src)),
 				    offset);
 				if (!(ch->flags & CHN_F_CLOSING))
 					ch->xruns++;
-#else
-				if (l < 1 || (ch->flags & CHN_F_CLOSING)) {
-					memset(buffer + l,
-					    sndbuf_zerodata(sndbuf_getfmt(src)),
-					    offset);
-					if (!(ch->flags & CHN_F_CLOSING))
-						ch->xruns++;
-				} else {
-					int cp, tgt;
+			} else {
+				int cp, tgt;
 
-					tgt = l;
-					while (offset > 0) {
-						cp = min(l, offset);
-						memcpy(buffer + tgt, buffer, cp);
-						offset -= cp;
-						tgt += cp;
-					}
-					ch->xruns++;
+				tgt = l;
+				while (offset > 0) {
+					cp = min(l, offset);
+					memcpy(buffer + tgt, buffer, cp);
+					offset -= cp;
+					tgt += cp;
 				}
-#endif
+				ch->xruns++;
 			}
+#endif
 		}
 	} else if (l > 0)
 		sndbuf_dispose(src, buffer, l);

sys/dev/sound/pcm/feeder.h

@@ -74,13 +74,14 @@ static struct feeder_class feeder ## _class = { \
 }; \
 SYSINIT(feeder, SI_SUB_DRIVERS, SI_ORDER_ANY, feeder_register, &feeder ## _class);
 
-#define FEEDER_ROOT	1
-#define FEEDER_FMT 	2
-#define FEEDER_MIXER	3
-#define FEEDER_RATE 	4
-#define FEEDER_FILTER 	5
-#define FEEDER_VOLUME 	6
-#define FEEDER_LAST	FEEDER_VOLUME
+#define FEEDER_ROOT	0
+#define FEEDER_FMT 	1
+#define FEEDER_MIXER	2
+#define FEEDER_RATE 	3
+#define FEEDER_FILTER 	4
+#define FEEDER_VOLUME 	5
+#define FEEDER_SWAPLR 	6
+#define FEEDER_LAST	32
 
 #define FEEDRATE_SRC	1
 #define FEEDRATE_DST	2

sys/dev/sound/pcm/sound.h

@@ -138,6 +138,8 @@ nomenclature:
 #define SD_F_SIMPLEX		0x00000001
 #define SD_F_AUTOVCHAN		0x00000002
 #define SD_F_SOFTPCMVOL		0x00000004
+#define SD_F_PSWAPLR		0x00000008
+#define SD_F_RSWAPLR		0x00000010
 #define SD_F_PRIO_RD		0x10000000
 #define SD_F_PRIO_WR		0x20000000
 #define SD_F_PRIO_SET		(SD_F_PRIO_RD | SD_F_PRIO_WR)